a Steel Box Section Build with SBR20 & Ballscrews Plus a few questions

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.

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Originally Posted by grain_r

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.

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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.

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.!!

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

With the mechanical stuff I think I got about 90% down on paper, the other 10% got designed ad hoc at the building stage.

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Originally Posted by grain_r

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.

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

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.ph...id=16159&stc=1 http://www.mycncuk.com/attachment.ph...id=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.ph...id=16161&stc=1
http://www.mycncuk.com/attachment.ph...id=16162&stc=1
http://www.mycncuk.com/attachment.ph...id=16163&stc=1
http://www.mycncuk.com/attachment.ph...id=16164&stc=1




http://www.mycncuk.com/attachment.ph...id=16166&stc=1

http://www.mycncuk.com/attachment.ph...id=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.

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:

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

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Originally Posted by grain_r

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.

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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:

Quote:

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Originally Posted by grain_r

. I started out wanting a welding trolley and what I have finished with is a welding go cart well al-right nearly finished.

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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

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Originally Posted by JAZZCNC

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.

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

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Originally Posted by cropwell

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

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

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:

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Originally Posted by grain_r

or just hold my breath and grow a pair. :02.47-tranquillity:

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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.

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/16144...s=true&ff13=80

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

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Originally Posted by cropwell

Zinc fumes can give you flu like symptoms, which can take 3 weeks to go.

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

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.

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.

Attachment 16827Attachment 16828Attachment 16829Attachment 16830Attachment 16831Attachment 16832Attachment 16833

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.

Quote:

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Originally Posted by grain_r

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.

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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.

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.

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.

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Originally Posted by grain_r

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.

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I've used a drill press to keep the tap straight whilst hand tapping....is that what you mean?

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.

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

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.

http://www.wickes.co.uk/Wickes-Brick...er-5L/p/153779

Vicious stuff, keep it away from your skin.

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Originally Posted by cropwell

http://www.wickes.co.uk/Wickes-Brick...er-5L/p/153779

Vicious stuff, keep it away from your skin.

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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.!!

Wow It all sounds like an outside job then. and if I ever don't want fingerprints there's the stuff. :cheerful:

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Originally Posted by grain_r

Wow It all sounds like an outside job then. and if I ever don't want fingerprints there's the stuff. :cheerful:

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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:

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:

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

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Originally Posted by cropwell

: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:

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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

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

Attachment 17092

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

Attachment 17093Attachment 17094Attachment 17095Attachment 17096Attachment 17097Attachment 17098Attachment 17094Attachment 17099

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.

Then You need a spot centre drill bit to start the holes.

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

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

Were there no cheap scrap accurate machines that could have been rebuilt.

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Originally Posted by Colin Barron

Were there no cheap scrap accurate machines that could have been rebuilt.

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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

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.