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

[njhussey]

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 . 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]

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.

[Lee Roberts]

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]

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]

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

[grain_r]

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

[grain_r]

So I still haven't finished my Frame still after a long long delay in making the CNC after house moves work and another daughter it's time to get this thing back on track again, when I started this I never in a million years thought I would still be making it.

Although I haven't been making any progress on my machine I read through the amazing posts on here most days still.



So I have been redesigning my original again and I have found that Item does a 45x90x90 10mm Profile

https://www.aluminium-profile.co.uk/...file-kjn992387

The plan would be to put the two together with bolting through one and then into 'T nuts on the second profile.

It will then be wider than the width of the frame to allow the full width of the cut (Which I didn't have previously)



I need to change the bracket so that it doesn't get in the way of the Z

It will have a movable shelf which I haven't added to the design in fusion 360 as yet so the spindle won't need to go right down to the bottom shelf.

It is roughly the same pricing as a 200x100 cold-rolled box section but I think it will be easier for me to complete the gantry with this instead of the steel and not have the resin to be put on to get the accuracy on the rails as time in the workshop is still limited these days.

Looking at the profile it seems pretty sturdy and it would have 5mm on each side of the rail to attach on the slots. But before I get too carried away with the design I thought I would check if this is a good possible profile to use.

Any thoughts would be most welcome.

Thank you

[Colin Barron]

Have a look at John Ward's site.
https://www.youtube.com/watch?v=Xbiipb6nnZg
You will achieve greater accuracy using flat plate fitted on top of your frame and shim at mounting positions.

[JAZZCNC]

Pointless using such a heavily built gantry on such a weak flimsy frame.! You seriously need to brace that frame-up.

[grain_r]

Good Morning

Thank you for the replies, Thanks Colin I will look through the link very appreciated, Thank you Jazz yes the actual frame that I have pretty much built most up and has more bracing of each corner and I'm adding diagonal pieces on the Horizontals of the bed and then the second top shelf (not shown) will also be bolted to the mainframe to add more rigidity.

Because I had that part built its more of the Gantry design I'm changing from the 50x50 box Gantry I originally had as my design to the Aluminium Gantry, but I wasn't sure if the Gantry would be as good and as strong as the 50x50 Box design I had previously,




The profile I'm thinking I using is this but I couldn't find too much about the strength of it in terms that I understood (Me not clever enough not Bosch's information)



I will use the Profile to create a stable base to connect it to the Plate. the Screw and mounts will be put on ali plates because of the room available on the 45mm and I need 60mm width for the screen bk12 fittings.


But I like the words from Jazzcnc used Heavily then I will continue along that route with my design I haven't ordered the profile as yet and I'm trying to get the rails on order soon.


I see Aliexpress and ebay don't seem to all say Hiwin rails now although the part numbers they use are still the same.

Fred shows that he sells original Hiwin still and also a 3rd party range which seems to be a lower cost but has anyone used these instead of Hiwin or is it just false economy and just go for the Hiwin rails?


Thank you

Rob