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View Full Version : BUILD LOG: a Steel Box Section Build with SBR20 & Ballscrews Plus a few questions



grain_r
25-09-2014, 05:17 PM
Hello All.
I'm certainly learning a lot as I read through the posts so thank you very much to the people that answer the questions but also ask the questions that I don't even know I want to ask.

I have come up with my design in sketch Up after finding I can't yet work out Autocad 3d (Although I guess it will come along as I progress)

I haven't as yet finalised my design but thought I would just see if you guys think that I am on the correct approach for my needs

I was a little silly and bought the rails and screws as a kit but i'm happy with the quality of everything I would have probably gone larger but it has its own problems so i'm going to use what I have.

at the moment the design is to use 50x50 Box section with the option of using 100x100 as the top for the rails and the screw next to each other. but I'm not sure whether I really need this ?

The bed is movable for creating a movable table for other things than sheet material and mould making. but I have capped the ends to that I don't have to use the bed as strength as much. It could be an issues if I put long material in but think I'm OK.

I'm using SBR20 rails for everything and SFU1605 screws all round

The project plan is to be able to cut a range of materials from Perspex , Wood & Aluminium, I also want the ability to end mill which is why the rails go right to the front of the machine giving the option to clamp to the frame but still working on that.

The plan is to use a 2.2kw Water cooling system and haven't really though what electronics to go fo as yet but thought I would see the weight of the machine first.

I think Sand in the box section is likely to dampen down any vibrations

I have made the gantry wider than the rails because I didn't think when I ordered the rails that I would be loosing some for the actual plates (Which is why I would have gone bigger)

The rails are 1100mm x 600mm x 280



I have put a design that I think I'm on the right road with but before I get too far thought I would ask you kind people if I am in the right road or if things should be changed ?

I thought I would put this as a build log because it will turn into one sooner or later anyway.


Thanks for looking


http://www.mycncuk.com/attachment.php?attachmentid=13452&stc=1

Rob Grain

grain_r
25-09-2014, 05:38 PM
I have though Mounting of the rail mounts on a 10mm Steel plate that is tig welded to the box section (Maybe Bolted for a little movement) ? and this way I can have the actual frame as wide as I like but just the cutting will then still be the same but this way I could put larger material on the frame and move it around if I ever wanted to e.g for cabinet doors at the moment I thing I would struggle to fit it on. and yes it is all because I bought before I thought ( I might use that saying again I like it)

I am still unsure if putting the gantry SBR20 rails would be the strongest design for the top and bottom or both on the front, or maybe have the one rail at the top and then the lower rails on the front.

I am really sorry I haven't used the X,Y,Z because I think I get it wrong when I say it, I thing Y is the movement of the whole gantry and the X is the movement of the across axis e.g. moving of the spindle left and right and I know I get the z Right 1 out of 3

If someone could confirm this or tell me I'm and idiot and have it wrong that would be much appreciated.

http://www.mycncuk.com/attachment.php?attachmentid=13453&stc=1


I have chosen the have a sliding Bolt through for the bed in the middle with a bracket tig'd on the box section and then I can bolt through to give extra strength but then at the ends just go through the actual box section of the base although I'm not sure if this will take away a lot of strength from the base.
also I though I would be best to mount the screw blocks on the outside of the gantry to stop dirt getting into the screw. there will be screws on each side to stop any problems however I am currently leaning to using 2 motors and not a timing belt but you might tell me differently.


http://www.mycncuk.com/attachment.php?attachmentid=13454&stc=1


Any comments would be very much appreciated

thanks for looking through and listening to my ramblings



Rob Grain

EddyCurrent
25-09-2014, 06:06 PM
Take a look at this diagram, you can see that in your design the spindle would hang out from the gantry well past the bearing blocks.

http://www.cncroutersource.com/do-it-yourself-CNC-router.html

It's usually regarded as X being the rails mounted on the frame, Y being the rails mounted on the gantry, Z where the spindle mounts.
Two motors on X works fine, just remember you would then need to, rate your power supply accordingly, purchase another stepper driver, add 2 home switches. It's generally regarded as advantagous to connect the motor to the ball screws using timing belts, the pulley sizes can also be selected to increase or decrease speed so that your stepper motor is working in it's optimum range while the cutting speeds are also optimum.
You might need this as you indicate 1605 screws all round, I'm using 1610 on X and Y which seems right using 1:1 ratio of pulley

Clive S
25-09-2014, 06:50 PM
Rob Welcome to the forum. Please don't buy anymore kit until you have your design finished its the biggest mistake people make. Ask as many questions as you can (a few at a time is better) and expect a bit of leg pulling but you will get all the advise you need on here.
There are generally two ways to drive the x screws either with one motor and a belt going to the other screw or using two motors one for each screw, there are for's and against both system. But they both function ok.
You will need more bracing of the frame that what you have. ..Clive

grain_r
25-09-2014, 09:11 PM
Thanks guys for that, I have put the spindle so that it will go past the frame so that I can cut on the end of material for letting on the sides of work, Although I suppose I am stopping me from being able to cut sheet as long as I would otherwise be able too. I have thought about moving the rails back a little and then making a clamp so that I could lamp it to the internal 'Y' support beam.

I thought I might be under building on the supports. Because I am going through the centre vertical beam I will have to have a change to get the support in. would it be best to brace from corner to corner or is it as strong if I triangle off the corners

I seem to buy the stuff and then learn and I have after many years started to come out of that routine things always work out but always a more difficult path and more stuff for the spares box.

grain_r
26-09-2014, 12:13 AM
Hello I have been doing a spot of re-design for the bracing Hopefully I haven't gone the other way with it now. I was trying to use a little less steel to keep the cost down but I would certainly rather have a stronger machine.

http://www.mycncuk.com/attachment.php?attachmentid=13455&stc=1

irving2008
27-09-2014, 07:31 AM
You don't need cross bracing at the ends, a single diagonal will suffice, run it in the opposite direction at the far end. One in the middle might be beneficial too.

grain_r
27-09-2014, 04:09 PM
Hey Irving2008 great thanks for that. I have made the change I haven't as yet put the middle support in, which I'm guessing that you mean through the centre of the base ?

http://www.mycncuk.com/attachment.php?attachmentid=13470&stc=1

that will be handy too im so close to being able to use x3 7.5 metre lengths so hopefully if I don't mess up cuts and welds I might get away with it. (So we all know I wont and will need more :witless:)

I'm leaning more to the timing belt option because it give me more options on configuration but I'm not sure How I will do that as yet.

Thanks very much for the advice so far it is really appreciated.

Thanks

Rob

Clive S
27-09-2014, 04:29 PM
If you put a brace in the centre you lose the ability to have a movable bed. ..Clive

JAZZCNC
27-09-2014, 04:39 PM
There's loads you could shave off this structure most those bits at the bottom are not needed. Something along the lines of this but narrowed down will work. You'll use less steel and still be plenty strong.
13472 13471

grain_r
27-09-2014, 09:44 PM
Hey Jazz
Thanks for the design, so if the parts missing at the bottom it doesn't get any-more twist of the table when in use ? or is the sheeting around it structural and stops this. I love the slider system I have been thinking that it would be not the easiest to lift the bed and get the bolts in, I imagine its just watch your fingers time as you take the last bolt out. your design is very much more evolved most certainly. and I love that there is space still underneath, Would you mind if I use your example I feel bad not making the design myself although I will change it to suit.

I'm sorry to ask so many questions but on the bracing does this have to be specific dimensions e.g. a true triangle for the strength like 45 degrees or just has to look correct. i'm not sure how easy it would be to make it belt driven the only think I can think of is to put the motor on the bottom of the bed and then use a pretty long belt in a 'v' shaping. I see the gantry uses ali extrusion I imagine I would still be better to use the box section for my design.

Thanks very much for the help.

Thanks

Rob

grain_r
14-10-2014, 04:55 PM
Hello Again everyone
I have been designing again and hopefully getting somewhere now thanks to the guidance from you guys. I'm not sure whether to go above the top rail and build up or if it is better to build downwards towards the table my thinking it that the strength of the side will help a little if it is below ? although I will have to shim with something to get a gap from the main frame. or would the gains (If any) really be worth it and just build on top?

http://www.mycncuk.com/attachment.php?attachmentid=13609&stc=1 http://www.mycncuk.com/attachment.php?attachmentid=13610&stc=1

EddyCurrent
14-10-2014, 07:04 PM
If you are using round rail on the gantry I can't help thinking it's best to have one on the top surface rather than both on the front.
You need to draw the ball screws and motor mounts in place before thinking it's done.

JAZZCNC
14-10-2014, 07:16 PM
Sorry to say this but that's a dreadful design. The gantry hanging down like that is acting as a lever and with no support at the ends it will resonate like crazy, this will show in the finish quality.
You need the Gantry supported at the ends connected directly to the sliding carriages.

grain_r
15-10-2014, 11:44 AM
Hey Guys. Thanks for that I would rather know that it isn't correct that's why I though I would post it up just in case I had it wrong. I will have another run at it.

Is the frame about correct for the design ?

My thought are to add one rail at the back and one on the top this way I think i can get less overhang on the Z axis face plate ? although this might be another silly idea. I have even thought about speaking to chai and seeing how much the linear rails would be but because I have the rails already I think i should persist with what I have and then upgrade when I have more knowledge and know what I am using the machine for.

I'm struggling in my own mind how to make the Z a little and because most seem to use linear rails the designs don't fit as easily. if anyone can point me to a design of the Z on round rails it would be much appreciated as a guide

Thanks as always

Rob

EddyCurrent
15-10-2014, 12:03 PM
Here's one, just search on Google for "cnc Z axis design" then choose 'images'

http://runawaybrainz.blogspot.co.uk/2012/09/cnc-building-diy-cnc-z-axis-without-cnc.html

grain_r
15-10-2014, 12:15 PM
Hey EddyCurrent Thanks very much for that that will certainly help me. didn't think of the Images part of google. :orange:

I was trying to incorporate your idea of one rail on the front/Back and one on the top or bottom but it seems to create quite a large gap on the back plate which I'm not sure if it will affect strength. I will get the pencil out I think.

Thanks
Rob

JAZZCNC
15-10-2014, 12:48 PM
Is the frame about correct for the design ?

Yes the only thing to watch is the amount of adjustabilty on the bed. If you don't need all that height then raise the horizontal frame supports.
Also doen't hurt to put some 4mm triangle plates on outside to help support the upper legs like in this pic.
13614


My thought are to add one rail at the back and one on the top this way I think i can get less overhang on the Z axis face plate ? although this might be another silly idea.
No not silly at all and machines are often done this way to allow ballscrews on front but like Eddy said before you need to include everything in the design ballscrews mounts the lot to see what clearences you have. Personally I don't like the Ballscrews on front and in firing line so put them at rear out the way or protected behind something with slot for access.


I have even thought about speaking to chai and seeing how much the linear rails would be but because I have the rails already I think i should persist with what I have and then upgrade when I have more knowledge and know what I am using the machine for.

Yes do it because there's far more work to upgrading than you realise so it will never get done and profiled linear rails are worlds apart from those round type rails so make the machine so much more accurate and reliable. With round type rails your constantly chasing the adjustment and they wear out and go sloppy in no time if not looked after. You don't get any of that with profile rails.!!
Chias prices for Linear rails are cheao and the quality is fine and you'll reap the bennifits 2 fold when you come to sell it.


I'm struggling in my own mind how to make the Z a little and because most seem to use linear rails the designs don't fit as easily. if anyone can point me to a design of the Z on round rails it would be much appreciated as a guide

Profiled or round there's really no difference other than clearence between front and rear plates and it's actually easier with round rail as they are deeper so you don't have to machine clearence for the ballscrew.
The design eddy posted is essentially how I make my Z axis which you can see here. I then put aluminium covers over them to protect every thing.
1361613617

grain_r
16-10-2014, 04:46 PM
Hey Jazcnc

Thanks very much for the great reply. I have looked through it and will add the corner bracing and I think I am going to go ahead with the build as original and then see what I actually use it for and then can build a higher accuracy machine with the initial machine later on down the line and I will have learned more about the subject.

I have had another look at the Gantry and I think I am much nearer on this design and I have tried to keep everything out of the way I still need to continue working on it but Just thought I would post it up to see if I'm on the correct lines this time.

I still need to work on the Motor and pulley details and the cable tray too.

I have been looking on aluminium warehouse and the pricing seems pretty good on there for 20mm there seems to be different qualities on there for not much difference in price.

http://www.mycncuk.com/attachment.php?attachmentid=13636&stc=1 http://www.mycncuk.com/attachment.php?attachmentid=13637&stc=1

JAZZCNC
16-10-2014, 05:56 PM
Wouldn't have the bottom rail that way around personally due to cutting forces and way it doesn't support the front plate. Personally would have top & bottom.
Also I wouldn't make the Y axis wrap around the gantry like that. It doesn't add hardly any strength makes the whole Y axis heavier than needed lowering accelration and increasing inertia plus it makes building harder because unless the Ends are perfectly 90deg they twist and bind the bearings.

Also rather than having the gantry cross beam central to the bearing try offsetting it back a little to allow for Z axis and spindle balancing the centre of Gravity better.

EddyCurrent
16-10-2014, 05:57 PM
The bearing blocks look too close together in the vertical direction to me.

grain_r
17-10-2014, 06:23 PM
Hey JazzCNC thanks very much indeed for that it sounds like I'm on the right track now, I did think about top and bottom but thought this might split the forces between up and down and back and forwards although doing it this way I guess the loads are on a single rail more for each movement. So will do I will go top and bottom which will be great to get rid of some of the material around the back. I didn't really want it there but it was the only way I could think off to get the rail around the rear to also try and keep it out of harms way too.

I am really sorry when you say move the rails back do you mean so that the spindle is inline with the upright box section of the gantry ? would it maybe worth going for something like 100x50mm box section for the sides and then put the 50x50 towards the rear to the spindle so it is more inline with the uprights of the gantry, I'm sorry if I've misunderstood.
Also on a side note I would like to thanks you very much for helping so many people on this community I have learned so much from you going through many peoples posts and its great to see people just trying to help each other out.

Also EddyCurrent the same goes for you going through peoples posts you are very helpful I just hope that I can get a machine running to be able to get the knowledge to put something back in.
Don't worry I'm not always a soppy sod.
I thought I might have the blocks a little too close but just picked the figure out of the air really for the distance. Is there an optimum or a way of determining the best gap ?. like most I was trying to maximize the cutting depth but because the bed moves I will add some more distance on it and just move the bed on each time I have a thought to making some fiberglass molds with foam for a dash board and though the more depth the better but I guess it will give a worse cut for other things I will have another go at it and go more in depth on the design now I know where I'm going with it all.

thanks chaps.

Rob

JAZZCNC
17-10-2014, 06:57 PM
I am really sorry when you say move the rails back do you mean so that the spindle is inline with the upright box section of the gantry ? would it maybe worth going for something like 100x50mm box section for the sides and then put the 50x50 towards the rear to the spindle so it is more inline with the uprights of the gantry, I'm sorry if I've misunderstood.

No was meaning offset back something like this for better centre of gravity and balanced bearing loads while cutting.13649

Regards bearing distance then I work on Half the travel required.!

grain_r
17-10-2014, 07:16 PM
Oh I see. great thanks I like that. So that I might save a little welding heat is there anything to stop me mounting the screw on the base of the box section although It won't be in the centre or is it best to put some uprights in and then mount to that ?

Thanks
Rob

grain_r
22-10-2014, 12:12 PM
I have been working on the updates and getting there now because I intend to make it my build log I thought I would keep updating with work in progress for my designs so people can see for the future . I'm getting pretty happy with the design now it seems to feel much better and thanks to you guys I am learning so much with each design change.

I am having a problem with the X axis I want to use one motor as people have suggested in the past because of Binding and using belts but I cant think of an easy way without using quite a few wheels to send it around the frame if I go directly across It would hinder the work pieces if they hang over the edge.

http://www.mycncuk.com/attachment.php?attachmentid=13678&stc=1 http://www.mycncuk.com/attachment.php?attachmentid=13679&stc=1 http://www.mycncuk.com/attachment.php?attachmentid=13680&stc=1

Any comments would be most welcome. I havn't put the cable trays or the front axis as yet thats being done at the moment.

Thanks

Rob

njhussey
22-10-2014, 12:44 PM
I know it's a bit more expense but why don't you make the Y axis rails longer and have the bearings spaced further apart on the top and botom rails? It would give you a stiffer machine and looks like the space isn't needed for cuting as you're rails are shorter than the Y axis already. Eddycurrent hinted at this in a previous post I think.

EddyCurrent
22-10-2014, 12:45 PM
For some reason I don't like the look of the box section as brackets for X ball nuts.
You seem to be loosing a fair amount of travel in Y direction by having short rails and ball screw.
Think about how you will access grease nipple on Z ball nut once it's all assembled.
Will you put adjustable feet on the frame legs for uneven floors ?
Can't see how you will adjust belt tension for the stepper motors shown.

njhussey
22-10-2014, 12:57 PM
Also think about how you will bolt it all together, you'll struggle to get the bottom Z axis bearings on as the bolt holes will be covered at the back so you'll have to take it all apart if you need to gt at them. If you extend the top Z axis palte back you can machine into it the adjusting slots you need and also it tucks the stepper down out the way and lowers the height of the Z axis.

Also don't forget that steel box section comes with rounded corners not nice square ones as you've drawn so you'll possibly need larger section (60 x 60) to be able to bolt the bearings to? I'd also extend the small plate you've got on the back of the Y axis for the floating bearing (small) mounting to provide a bit more stiffness for the Y axis, that way you'll not need any diagonal bracing.

If you're not sure what I mean attach the sketchup file (if that's what you're using?) and I'll show you what I mean.

grain_r
22-10-2014, 01:02 PM
Hey guys Thanks very much for the replies, Unfortunately I was a silly boy and bought the supported rails kit before I knew anything about the subject from Aliexpress. the plan being I will use what I have for now but then look to either create another or upgrade to rails. I have made it wider also so that I can slide work pieces around a little and work with larger materials and then make a second continued cut although most of the things I do will be sheet material and smaller pieces but I wanted an all-rounder for things like my daughters dolls house I intend to make with the machine and other toys too for her and me !

I didn't even think about the tensioning in all honesty that is a very good point I will make it on a movable faceplate. I couldn't think of a different way for the box for the ballnuts otherwise the other option being the ali route but though this might be better on the strength I might be able to make a silicone hose to the grease maybe although I'm not sure if it would just pop off.

I will have a good think to see if I can make those better

Thanks so much guys.

grain_r
22-10-2014, 05:38 PM
Hey Neil

Thanks very much for the offer of explaining it on the drawing I did try to attach the file but it doesn't seem to like it it seems like it only lets me do standard graphics formats. Is there another way to get it to you.

Thanks very much.

Rob

irving2008
23-10-2014, 02:04 AM
Zip the file up, or add .Zip as an extension...

grain_r
23-10-2014, 03:23 PM
Hello Neil

Thanks for the PM although thought it might be easiest to try what irving2008, Many thanks for that irving2008 much appreciated.

13682

I'm sorry if the dawing isn't upto much I'm going through a learning curve on sketch up too this is the first time I've used that I try to keep the layers seperate but I forget to change to the correct layer sometimes.


Many thanks for the help

Thanks

Rob

njhussey
23-10-2014, 03:25 PM
Hmmm....I've only got version 8 and can't open it.....flipping typical!!

grain_r
23-10-2014, 03:31 PM
Hey Neil No Worries, I've just saved it as a version 8 & 6 Just in case and that will hopefully work.

13683


Thanks

Rob

EddyCurrent
23-10-2014, 03:33 PM
I was too slow, beaten to it haha

grain_r
23-10-2014, 03:45 PM
thanks very much for doing it all the same. :encouragement:

njhussey
23-10-2014, 03:57 PM
Quick tip....when creating a part, say a 50 x 50 leg, once you've created it select it all and right click and create a group. It's much easier to move it, rotate it etc. without messing about with the other parts it's placed next to. Might be teaching Granny to suck eggs but I've just tried moving some bits and it's creating some interesting shapes....

EddyCurrent
23-10-2014, 03:58 PM
Just a thought.
If you made the Z backplate wider, keeping the Y bearing blocks where they are due to short rails etc. you could then move the Z bearing blocks wider and fit a wider Z front plate.
This might give you the opportunity to mount the spindle in 3 positions, left, right, centre, not ideal but maybe useful ?
Or maybe you could then mount another device beside the spindle such as a laser head, 3D printer head ?

grain_r
23-10-2014, 04:09 PM
Hey Neil,

I'm sorry about that your certainly not teaching granny, I gone more on the lines well that seemed to make the shape I want at the time. I will certainly group then from now on the makes a lot of sense I tried to do it with layers instead of the grouping and then selecting the layer to move things around. Although I certainly got further on sketch-up than on Autocad 3d up to now that's next weeks job then (Well Maybe)

Thanks Eddy that sounds like it would be worth a look at I also though about a plasma cutter for the future for stainless although thats as far as I've gone with it. I appologize not having used one of these things would I be able to set a home and then use different paths for the further cuts ? I'm certainly not worried about having to swap the spindle around between then that would get the hoped for cutting area when I forgot about the bearing blocks when I felt like a shopping trip before I knew anything at all.

thanks

Rob

EddyCurrent
23-10-2014, 04:26 PM
I appologize not having used one of these things would I be able to set a home and then use different paths for the further cuts ?

Rob, I think this is what you mean.
Home switches use the 'machine coordinates' whereas the work piece you are cutting uses 'machine coordinates', so a search for those terms should bring up some further reading.
Like a piece of graph paper the home switches will be at 'machine coordinate' X0,Y0 and if you clamped a piece of wood on the table for example and moved your spindle to the bottom left corner, that could be your X0,Y0 'work coordinate' and that's what you typically set to zero in Mach3 for example so that X0,Y0 in your g-code starts cutting in the right place.
So really you can give the machine an X0,Y0 work ccordinate starting point just about anywhere on the cutting table.
Think of the machine as big piece of graph paper that is in a fixed position (machine coordinates) and the work piece as a smaller piece of graph paper that can be moved about on top of it (work coordinates).
So on a 900 x 600 machine, if you put a workpiece with it's bottom left corner in the middle of the bed, that corner might have 'machine coordinate' X450, Y300 and 'work coordinates' X0,Y0

There's also offsets/fixture coordinates that could be usefully employed; http://www.cnccookbook.com/CCCNCGCodeG54G92WorkOffsets.htm

grain_r
23-10-2014, 04:30 PM
Ah OK so if I had a movable spindle on the plate I can just set the coordinates on the work piece and then even thought the spindle has moved Mach3 would still know where to start from, from that same cutting path, I Wouldnt have to reset back to 0,0 and then get a new cut path. to get a continuous cut.

EddyCurrent
23-10-2014, 04:46 PM
Ah OK so if I had a movable spindle on the plate I can just set the coordinates on the work piece and then even thought the spindle has moved Mach3 would still know where to start from, from that same cutting path, I Wouldnt have to reset back to 0,0 and then get a new cut path. to get a continuous cut.

That's right, as long as you tell Mach3 where work 0,0, is you're good to cut.
I've just realised you might be considering moving the spindle in the middle of a job, that's going to give you problems but could be done if planned for in advance, you could split the job up into, 'sub jobs' for example.
I would stick to, one job = one spindle position.

JAZZCNC
23-10-2014, 05:03 PM
Hi,

Just looked at machine drawing and it's looking nearly there but 2 things both been picked up on and one Neil pointed out but think you've missed is the Z lower axis bearings conflicting with bolting together. This is a common Err that I and many others have done in the past so don't beat your self up. lol

The Long ballscrew mounting needs some attention.! These are areas where you need some adjustabilty for setting up and alignment so you will be best to mount the End bearings on plates that can be easily adjusted and like wise the mounting point on the Gantry needs to be more accessible. Try not to make the screw go thru the fixed mount but rather have ballnut mount that bolts to the gantry drop plate.
This will make screw alignment much easier and allow finding best performance just that bit simpler.!

Looking good and will soon be time to put the pen down and start cutting.!!

grain_r
23-10-2014, 08:51 PM
Hey guys

Thank you very much for the really very useful comments. I thing whilst I'm starting out I might keep the single mounting point for the Spindle until I get how the 0,0 work piece co ordinates work I've got a feeling I would be getting a few odd results with me trying to use it on cuts with moving the spindle and get steps in a continuous lines. Although I think it will certainly be a thing that i will make a new front plate. The good thing is that i can move the work piece around a a little side to side but sounds like I will get a similar problem with the cuttings again.

Hey Jazzcnc Thank you very much for the comments I really didn't spot that with the conflict on the mounting of the bearing blocks fantastic spot. I will move the bearing blocks,
By having the long axis blocks on a plate that will give me the distance that I need to not have to shim the mounting on the gantry. It sounds like I might be best to use 20mm aluminium for the screw connection to the gantry.

I'm still not sure on running the screws with one motor either the only way I can see at the moment is running 2 motors. I don't want to really have the belts running across the rear just in case I want to use long material that can hang over the edge.

I'm really looking forwards to building something that I have plans for now instead of designing on the go.

Thanks very Much

Rob

EddyCurrent
23-10-2014, 09:52 PM
With the mechanical stuff I think I got about 90% down on paper, the other 10% got designed ad hoc at the building stage.

JAZZCNC
24-10-2014, 12:45 AM
I'm still not sure on running the screws with one motor either the only way I can see at the moment is running 2 motors. I don't want to really have the belts running across the rear just in case I want to use long material that can hang over the edge.

Nothing wrong with using 2 motors provided it's done correctly and they are run well within there capabilty's and using good electronics.!

grain_r
23-09-2015, 08:59 PM
Good Evening well I have been lurking on here for a while again and watching everyone making steps forward. I have ordered placed and collected my box section although if I did it again I would opt for 5mm instead of 3mm steel as I think I have given myself a few mini headaches of threading and bolting and would have only been another 50.00 but oh well you live and learn.

http://www.mycncuk.com/attachment.php?attachmentid=16159&stc=1 http://www.mycncuk.com/attachment.php?attachmentid=16160&stc=1

The total metal cost was really good I thought I would put the costings on here to help people designing machines as a basis pricing although this price was specific to my machine.

X1 - Cut List 500 MM 5mm x 50mm Flat Bar 5.00 each
X2 1300.00 mm Top Rails
X4 550.00 mm Legs
X2 1032.00 mm Side Bars
X4 287.00 mm Side Uprights
X8 230.4mm Angles
X3 950.00 mm End Support & Mid Supports
X2 95.00 Table Ends
X2 1032.00 mm Table Middle Lengths
X2 850.00 Table Middle Supports
X2 952.00 Gantry Horizontals
X2 200mm Gantry Seats
ALL OF THE BOX SECTION IN 5MM 155.00 LUMP SUM
ALL OF THE BOX SECTION IN 3MM 100.00 LUMP SUM

I had the metal cut because as I said in the email to the company that was cutting it I wouldn't be able to get as accurate as they would, (Well that certainly wasn't true) the cuts are withing 1mm as they said but that just happens to be on the one side they are really out. but at least it did all fit in the car this way oh well.

I thought it might take an eternity to get the accuracy with a file and so I have now purchased a SIP sander & Lanisher (I have always wanted one anyway so a nice justification :untroubled: ) I know it says no metal but it is really good and I am now getting the ends half correct and then finishing them on the Sander it is so well built it doesn't complain at all so I will certainly be buying SIP again.


Well it has then sat there for a while and so the other night I just had to sit there and measure every piece and I have now labelled everything (I should have done this before) and it now makes sense again. also if I had done this straight away when I bought the metal I would have found that my top rail was not in the pile so I will get another and this time I'm cutting it. at least I will get to play with the sander again.
Not a single piece of wood is safe in my garage. :chuncky:


I have been learning tig welding for the project by making a welding trolley as everyone always seems too and I am needing the grinder less now. so its all relevant for the project, I always seem to be going the other way and start making something else to make the next thing in the chain.

http://www.mycncuk.com/attachment.php?attachmentid=16161&stc=1
http://www.mycncuk.com/attachment.php?attachmentid=16162&stc=1
http://www.mycncuk.com/attachment.php?attachmentid=16163&stc=1
http://www.mycncuk.com/attachment.php?attachmentid=16164&stc=1




http://www.mycncuk.com/attachment.php?attachmentid=16166&stc=1

http://www.mycncuk.com/attachment.php?attachmentid=16165&stc=1
Well at least its all practice. I started out wanting a welding trolley and what I have finished with is a welding go cart well al-right nearly finished.

JAZZCNC
23-09-2015, 09:19 PM
Hi rob,

Nice to see you back again thou would nicer still to see pics of a welded frame so get the welder fired up and lets see some action. . Lol

Don't worry too much about only being 3mm it still taps and holds threads with smaller bolt sizes. If you need larger bolts in places you can't reach back of then there's other quick and dirty ways like drilling larger hole and inserting a nut weld in place and grind flat.

So now go away and don't come back without pics of a welded frame. . :thumsup:

grain_r
23-09-2015, 10:35 PM
Hey Jazz

You didn't say the frame had to be a CNC machine :lemo:

thanks for the advice on the bolts. I like the idea of welding the nuts into the frame and grinding them. you say drill them but with my welding skills as they have been it will just be nice to fill some of those holes that just seem to appear in the metal when the tig torch is close. I have brought 2 boxes of screwfixes finest M5 Allen bolt selection boxes (And not even Christmas).

Thanks

Rob

JAZZCNC
23-09-2015, 11:37 PM
you say drill them but with my welding skills as they have been it will just be nice to fill some of those holes that just seem to appear in the metal when the tig torch is close.

Tig.!! . . . You shouldn't be blowing holes with Tig.!! . . . It's like welding with chocolate sauce it's so smooth and controllable.!! . . . . Go watch a few more videos on setup. . Lol . . . .. Or try it with your eyes open this time. . .:hysterical:

Edit: Just seen pics and there spot on welds mate well done. Tig isn't easy thing to learn so your doing well. . :yahoo:

JAZZCNC
23-09-2015, 11:57 PM
. I started out wanting a welding trolley and what I have finished with is a welding go cart well al-right nearly finished.

Grass has nearly stopped growing so rip out the engine and throw it on the trolley and you'll have the CNC machine finished in no time. . . Lol

cropwell
24-09-2015, 12:06 AM
Hi rob,
If you need larger bolts in places you can't reach back of then there's other quick and dirty ways like drilling larger hole and inserting a nut weld in place and grind flat.


Or use riv-nuts if you can't be arsed to fart about with welding :witless:

JAZZCNC
24-09-2015, 12:24 AM
Or use riv-nuts if you can't be arsed to fart about with welding :witless:

Cum-on I'm a Yorkshire Man have you seen price of them buggers.!! . . . . . Can get 100 nuts for price 10 of them.!!

grain_r
24-09-2015, 11:43 AM
Hey Jazz

Thanks for the kind message.I think its getting there but i don't always get the same results every time at the moment. but I absolutely love welding now it still amazes me. I want to be confident enough to weld some of the chassis on the car and not need to ask a friend it they might like a ride in it first (Just in-case :tongue:). I think because I'm teaching myself there is probably a lot of bad habits going to be there.

I did think if riv-nuts originally but it seems that if any vibration occurs then these would start to wonder about a little. I really love the idea of welding the nuts in. I'm a worrier and I have used the sander to take the zinc coating off but it says somewhere the gasses are pretty bad for you. I'm not sure if there are specific welding quality nuts around or anything ? or just hold my breath and grow a pair. :02.47-tranquillity:

JAZZCNC
27-09-2015, 12:32 PM
or just hold my breath and grow a pair. :02.47-tranquillity:

None of the gases given off are exactly good for you so if welding for long time or anything you know isn't sweet smelling then wear a mask.! I wear mask all the time when welding.

cropwell
27-09-2015, 01:50 PM
Zinc fumes can give you flu like symptoms, which can take 3 weeks to go. It is probably best to wear a good quality respirator and work in a well ventilated area. Zinc inclusion in the weld won't really happen as the zinc will burn off, but for the sake of your health it is better to sand it off, while wearing a mask as the dust is just as poisonous. A lot of heavy metals are cumulative poisons as the body can't get rid of them. Fortunately zinc can be dealt with by the body.

Have fun welding !

Thes might be what you want http://www.ebay.co.uk/itm/like/161447323877?adgroupid=&hlpht=true&hlpv=2&rlsatarget=&adtype=pla&ff3=1&lpid=122&poi=&ul_noapp=true&limghlpsr=true&ff19=0&device=c&chn=ps&campaignid=&crdt=0&ff12=67&ff11=ICEP3.0.0-L&ff14=122&viphx=1&ops=true&ff13=80

https://en.wikipedia.org/wiki/Weld_nut

JAZZCNC
27-09-2015, 02:33 PM
Zinc fumes can give you flu like symptoms, which can take 3 weeks to go.


Just got your self a new forum title.!! . . . Doc Crop. .:victorious:

grain_r
01-10-2015, 06:03 PM
Hey Cropwell

Thank you very much for the explanation and I will certainly wear a mask in future and I'm getting those bolts on order to make me worry less.

grain_r
17-12-2015, 12:32 PM
Well I thought I would keep my progress on here. Unfortunately It's not quick but going the right way.

I have made the frame sides and tacked the end screw plates on. Everything has been sanded down with a disc sander to give the best possible accuracy and then I have used my trusty Digital Vernier calliper although I have also made the screw holes larger diameter for a little fettling movment of about 1/2 mm Just in case.

16827168281682916830168311683216833

The next step is to start drilling my holes for the Threads. I have chosen M5 allen screws and I have ordered a cobalt 4.2mm drill for the threads.
I just need to experiment getting the hole exactly centred for the thread holes to be as accurate as possible.

Neale
17-12-2015, 02:47 PM
The next step is to start drilling my holes for the Threads. I have chosen M5 allen screws and I have ordered a cobalt 4.2mm drill for the threads.
I just need to experiment getting the hole exactly centred for the thread holes to be as accurate as possible.

Couple of tricks that you might not have come across. One is to start the hole using a clearance drill that nicely fits the hole in the mating part. Just drill lightly to give a centre mark then switch to the tapping size drill which, with a bit of luck, will follow the first mark. That doesn't guarantee that the hole is square to the work, though. I use a small steel block (turned from an odd scrap of steel) with a projection on one end that fits the clearance hole, and a hole up the centre that takes the tapping size drill. That helps a lot when you are using a hand-held drill in awkward places. Don't know if you have the facilities to make something like this (very easy lathe job) or perhaps know someone who can help? I find that I can go through in one pass with the 4.2mm drill, hand-held, but anything much bigger than that can do with a smaller pilot hole first (much easier going through steel) and then open up with the correct drill.

One other tip, if you're not doing it already - get the right taps! For through holes in steel, use a spiral-point tap. For blind holes, use a spiral-flute tap. Avoid using conventional hand taps (straight flutes) if you can. They are hard work and you find yourself going in a half-turn, then backing off to release the chips, then every so often bringing it right out to clear the flutes. The spiral-form taps are designed to push the swarf in front or bring it up the flutes, and you can tap in one pass without backing off all the time. They're cheap enough from China (I recently bought a couple each of M4/M5/M6 plus one M8, and the whole lot, including postage, was just over a tenner). Well worth while.

njhussey
17-12-2015, 02:53 PM
Get yourself a centre punch set. Select the exact punch size for the clearance hole and punch through to mark for the 4.2mm drill. Use a clamp in one side whilst punching the other so it doesn't move....simples. Punch set is about 13 + delivery I think.

grain_r
17-12-2015, 04:16 PM
Hey gents

Brilliant thank you very much for the tips. Unfortunately I don't have access to a lathe although the occasional eBay search has been done :thumsup:. I thought I might be able to achieve a similar creation by glueing some washers together in a stack on a plate to keep it all true. I have seen that people also put taps into the drill press and do it this way that I thought may be worth a try.

njhussey
17-12-2015, 04:27 PM
Hey gents

Brilliant thank you very much for the tips. Unfortunately I don't have access to a lathe although the occasional eBay search has been done :thumsup:. I thought I might be able to achieve a similar creation by glueing some washers together in a stack on a plate to keep it all true. I have seen that people also put taps into the drill press and do it this way that I thought may be worth a try.
I've used a drill press to keep the tap straight whilst hand tapping....is that what you mean?

grain_r
17-12-2015, 04:34 PM
Hey Neil

Yes just to keep it straight really and manually turning the drill. although press the button and you have your own indoor heli.

cropwell
17-12-2015, 07:26 PM
Just an addition to the problem of zinc and welding :-
I use brick acid to take off the zinc. If you can't get self colour nuts then dip your nuts in brick acid :whistle: Take them out when they stop fizzing and rinse them.

Happy holiday,

Rob

grain_r
17-12-2015, 08:41 PM
Hey Rob

Thanks very much for that. I will have a look for brick acid. I haven't heard of that before I guess it is for cleaning mortar from bricks so I will have a look at the builders for it ? I saw a video recently that Ron covell uses some acid to do that too. I did look for the weld nuts in a larger size for the CNC feet but I think I will use the acid instead.

Thank you very much.

cropwell
17-12-2015, 09:36 PM
http://www.wickes.co.uk/Wickes-Brick+Mortar-Cleaner-5L/p/153779

Vicious stuff, keep it away from your skin.

JAZZCNC
17-12-2015, 09:58 PM
http://www.wickes.co.uk/Wickes-Brick+Mortar-Cleaner-5L/p/153779

Vicious stuff, keep it away from your skin.

That's Cat piss for brick acid it's only 5% active our Chip shop Vinagar is stronger than that. .:cower: . . . . Good Hydrochrolic brick Acid is 28% now that will make your tongue curl.!!

Oh and fumes from Hydro Acid are just bad if not worse than those from Galv so be careful.!!

grain_r
17-12-2015, 11:04 PM
Wow It all sounds like an outside job then. and if I ever don't want fingerprints there's the stuff. :cheerful:

JAZZCNC
17-12-2015, 11:11 PM
Wow It all sounds like an outside job then. and if I ever don't want fingerprints there's the stuff. :cheerful:

Def outside job with mask plus eye protection. The fumes from Acid are just has bad the stuff it's self so be careful.

Oh and You wan't Sulphuric acid to get rid of Finger prints! . . I can let you have some if you like. . :hysterical:

grain_r
17-12-2015, 11:22 PM
I hope I never upset you, If you offered me a drink i'd certainly think twice :playful: i'm trying to work out if you have a workshop or and evil genius lab. :chuncky:

cropwell
17-12-2015, 11:59 PM
Yes Jazz - I know all this and more (chemistry at Uni), thats why I recommended the Wickes stuff. It will get the zinc off in about 15 to 20 minutes and is not as dangerous as more concentrated hydrochloric or sulphuric acid. I am not so sure about chip shop vinegar, acetic anhydride would do the job, but I certainly wouldn't want to inhale the vapours of that stuff.
:joker: I have been told that in Barnsley, the pigeons fly backwards to avoid getting the shit in their eyes. Is this true Dean ?:yahoo:

Happy Holiday.

Rob

JAZZCNC
18-12-2015, 12:47 AM
:joker: I have been told that in Barnsley, the pigeons fly backwards to avoid getting the shit in their eyes. Is this true Dean ?:yahoo:

Ye along with we all wear Flat caps and have Whippits mi old Cock.!! . . . . n wi av r own X factor darn intarn called B factor n ter's latist winners..


https://www.youtube.com/watch?v=ThaVUS3vuzE


https://www.youtube.com/watch?v=nLWfIiw9hpo

grain_r
03-01-2016, 11:04 PM
Hey all

Well I though I would pop a couple more pics on here as I'm doing bits to keep me motivated too. I'm having a tapping Issue for some reason at the moment. I have used a 4.2mm Cobalt drill bit and I have used a centre punch and then I have used the cobalt but it wanders I have then even turned the pillar drill by hand a few times and I was surprised but it did cut which I guess is because its a new drill bit and then started it and unfortunately it still wandered so I stopped it and put a little pressure on the work piece and then started the drill and that works better but still not good. I think My holes have then gone oval even when the wandering stops when in a decent start for the bit.

I'm thinking I might even get a better job done with a hand dewalt battery drill. Yes I know its a cheap drill but Would have thought it should drill holes but maybe its me.
I have even tried to use a stepped drill of 4mm and better rigidity but they are the worst with one side ok and the other only 1 thread

The Culprit

17092

The Holes (Although it does screw in and hold when tightened but not right somewhere)

1709317094170951709617097170981709417099

I have ordered a new tapered tap but wondering if the 3mm just isn't thick enough. Luckily On this bit I can put nuts on them but won't be able to weld them on.

Oh Well I will carry on.

JAZZCNC
03-01-2016, 11:23 PM
Then You need a spot centre drill bit to start the holes.

Lee Roberts
03-01-2016, 11:43 PM
Typically you would spot drill the hole first with a spotting drill bit (like a normal bit but shorter and so stiffer) or a center drill bit, a smaller diameter drill bit maybe used as/or well, just take your time as they snap easily at those sizes.

I can't see this would be a problem with your bench drill though, would continue to use it instead of going free hand personally.

.Me

Edit: Not sure if you've settled on a Z Axis design yet but here is a link to how I've done mine using 20mm plate and TBR16 round rails:

Link: http://www.mycncuk.com/album.php?albumid=387

grain_r
26-04-2016, 01:54 PM
Hey Everyone

I have been working Away at the base still and we have a new baby Daughter arrived too. So not too much work been done.

But the internet is a cruel master I have been looking at all of the threads and it seems like Hiwin is the way to go and sell the Supported SBR20 Rails ?

I have been looking at the 20mm and 25mm but I'm unsure if the bigger is better rule applies on this. I am just thinking that once all of the holes are in the nice new steel and the aluminium it will be best to swap now especially how long it takes me to do anything.

I think my design will still be good for the rails instead of any changes I have had a look at chai's site on Ali Express but seems more expensive than others but is Hiwin the same from everyone and they are just suppliers or are there differences in the quality of these things.

Thanks everyone.

Rob

Colin Barron
01-09-2016, 09:04 PM
Were there no cheap scrap accurate machines that could have been rebuilt.

grain_r
02-09-2016, 10:37 PM
Were there no cheap scrap accurate machines that could have been rebuilt.
Hello Colin I think that if something comes from your head and you build it you achieve knowledge if nothing else.

I have bought unfinished projects for other things before in life and they are rarely a simpler and cost effective way of doing things and normally a compromise in design and quality.

That said I imagine there are some very good machines out there that have started life as another machine.

The build is taking quite a while to get the frame finished but I'm certainly enjoying every second of the process.

Thanks

Rob

Colin Barron
03-09-2016, 10:38 PM
A very small drill bit can be used to find the centre spot made with centre punch,(spindle not moving), work should be clamped lightly but adjustable, clamp the work tight when positioned and check again to confirm it has not moved. Drill a small hole to confirm position then full size. A smaller drill bit will not move off centre as much as final size. If you still have problems use a centre finder (point) as shown here. https://www.youtube.com/watch?v=RhtBdar4iVg . I was informed as an apprentice many years ago that using the pointer method an accuracy of 1/64th inch (0.4mm) is achievable.

Colin Barron
03-09-2016, 11:25 PM
How do you propose to get the main axis shafts level and parallel with each other? Commercial companies using this style of frame will have accurate jigs to hold the frame in position while they weld it. Special purpose machine makers mount rails onto a flat ground plate, which is mounted onto the frame, to ensure flatness. With the flat plate and one shaft mounted you could check parallelism using a dial indicator to locate the position of the other shaft.

grain_r
12-09-2016, 09:34 PM
Hey colin

Sorry for the Delay in replying. I have given myself room to move components for small adjusting of plates which is lucky too because as previously said I just cant get the holes as close as I would like. although I centre punch and then centre drill and then go larger but I think with my newer drill press it has got better. But i have made 6mm holes in the plates that bolt to the m5 tapped holes so that will give me a small amount of movement.

I have a dial indicator to get as close as I can although I need to find a long enough straight edge to trust and then using the Vernier caliper too.

I will then be able to then flatten the spoil board once everything is running so it won't matter if the machine is a small part of a mm out because it will al be parallel with itself and also the work piece.

Well that's the plan anyway. I will be using Epoxy for the rails to get the top rails flat running a channel between the rails and this will then self level.

i think then it will be a lot of fiddling about to chase every last 0.0 of mm

I would be great to have those known flat and precise equipment of the manufacturers have but money would never allow for it sadly.

thanks

Rob

Colin Barron
12-09-2016, 11:06 PM
What about using a laser level and laser distance measure. If you are careful you could use a sheet of glass to check for level.

grain_r
12-09-2016, 11:08 PM
Great idea I didnt even think about glass I will be keeping my eyes open when I pass any skips from now on.


What about using a laser level and laser distance measure. If you are careful you could use a sheet of glass to check for level.

Colin Barron
12-09-2016, 11:15 PM
Best look for old double glased unit the edges are taped and safer, wear gloves and glasses.