DIY Linear Bearings

[CraftyGeek]

Ok - so it looks like its about turn time & back to the drawing board.
Are we talking 50mm x 3mm mild steel box?

It'll be bolted, not welded as I don't have the gear for that - but I do have a pillar drill & some taps, so should be able to cobble something pretty sturdy together.

Screws - i was looking at a Marchant Dice package on ebay...but given that i'm now looking at supported rails from Chai, i think it makes sense to get some screws from him as well - i'll need to look at what he offers & the pricing. If the steel does work out that much cheaper, then the budget shouldn't be an issue.

I'll call my local metal supplier tomorrow to get a quote for the steel box & then start drawing something up.

[irving2008]

Also, if you're following that design..... don't... the single central screw for the X-axis will cause you hours of pain if you plan to cut anything stronger than cheese at the full width of the Y axis. Plan and budget for two screws and either 2 drives & motors or a single motor and pulley system unless you make the x-axis bearings really long to counteract racking. Go re-read some of the build logs, its been discussed in depth many times. If you're investing in a serious machine, best to get it right at the outset!

[JAZZCNC]

Also, if you're following that design..... don't... the single central screw for the X-axis will cause you hours of pain if you plan to cut anything stronger than cheese at the full width of the Y axis.

While I agree completely 2 screws are best route in this case it's marginal Irving has he only wants 600mm cutting width, if he has wide enough bearing spacing on X axis and builds ridged Gantry it will be fine for upto light Aluminium work. On a budget this will work fine and with bit of thoughtful design could easily be incorporated later if needed.!!. . . . .Carry on Sir I say.

Are we talking 50mm x 3mm mild steel box?

I'll call my local metal supplier tomorrow to get a quote for the steel box & then start drawing something up.

Yep 50 x 3mm and the last time I bought some which was 2-3months ago it cost me £26 for 7.5mtr length. That's was plus vat but if like my friendly supplier they will some times do without Vat.

[irving2008]

While I agree completely 2 screws are best route in this case it's marginal Irving has he only wants 600mm cutting width, if he has wide enough bearing spacing on X axis and builds ridged Gantry it will be fine for upto light Aluminium work. On a budget this will work fine and with bit of thoughtful design could easily be incorporated later if needed.!!. .

Ok, on that width maybe you're right, but in that case the X bearing spacing on that design is nowhere near wide enough IMHO, so don't underestimate the extra X travel length.

[CraftyGeek]

Cheers chaps - My original plan was to build it using a single x-axis screw...see how it goes then add a second at a later date if I feel I need it.

I'm now ditching the FLA-100 as a base design & am starting a new design from scratch with 50mm box.

My local supplier states £4.10/m +VAT as a base price, then depending on quantity it could be cheaper...they also quoted for cutting - 50p/cut as a rough ballpark but cheaper on multiples.

I'll get a bit further with the design & then start a build thread - then you can start ripping my plans apart again ;-)

[JAZZCNC]

I'll get a bit further with the design & then start a build thread - then you can start ripping my plans apart again ;-)

We don't Rip apart we give Con-crushing Criticism.!! . . . Opp's mean constructive Criticism.

So 4.10mtr = £30.75 for 7.5mtr, so that's same price has just 2mtr of Alu Profile or put another way you get 5.5mtr free for same money. . . . . Bit more pleasant on the Old wallet isn't it.!!

Crack on and let the fun begin.

[CraftyGeek]

Yep - t'is cheaper...but more work involved in assembly.

One more question while i'm designing...
I've been thinking more about dual leadscrews with a single motor for the x-axis - what's the most cost effective way of doing this & a good place for parts?
(looking more at costs rather than exact setup at the moment)

[JAZZCNC]

Yep - t'is cheaper...but more work involved in assembly.

Not has much work has you may think, profile still has to be drilled, tapped etc and it's not always easy has folks think it's shitty stuff to drill and even worse to Tap good threads into.!

One more question while i'm designing...
I've been thinking more about dual leadscrews with a single motor for the x-axis - what's the most cost effective way of doing this & a good place for parts?
(looking more at costs rather than exact setup at the moment)

The best way is to use 15mm HTD timing belt and pulleys running around 2 idle bearings to central motor.
Your local bearing company may be the best place to ask, I use lots belts & pulleys and this what I find cheapest. . . . But failing that then there's likes of Bearing boys etc on-line. If you look around the forum others have posted links to places they've bought.