Quote Originally Posted by CNCUK View Post
If its any help to you mate i have got a few of the 608zz's with the zz's missing, there is nothing wrong with the bearings other then the zz missing on one side. I get the odd one or 2 now and again like that so i just use them for testing out ideas as i wouldnt sell them on like that.

I'v also got x4 SK12's sat in my office as well, but i'v just had a look and they wont be big enuff for the 608zz's. i have got lots of SK20's so you could bore them out to 22mm for the 608zz's to fit into?

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I'v now made this as another solution also in the hope people will find them usefull:

If you want some SK20's buy them from my ebay shop and let me know your ebay ID and ill send you the bearings for free. Also wait for me to send you an invoice as i can more then likly do you somthing extra on the invoice as well :).

Cheers,
Lee
Lee, thanks for that, I may need some more 12mm round rail too so I'll be back to you when I've worked out exactly what I am going to do.

I was thinking that SHF20's bored out would also work as per your solution above (is that Delrin?)

I note your leadscrew runs the entire length of the axis. Although it doesnt need to - asuming the connection with the table is in the middle of the table then the leadscrew only needs to be 1/2 the table length plus supporting/machining allowance. This does mean that the end bearing in under the table and not at the end like yours. Apart from the more complex mechanical arrangement is there any other reason not to do this? I'd rather not buy any more 10mm x 2 leadscrew.

Robin - the leadscrew is whatever MarchantDice sell - carbon steel I think.

I'll admit I got a bit carried away and bought their package of 3 lengths - 400mm(X), 350mm(Y), 250mm(Z) - and 3 Delrin nuts before I really thought things through :), and I know know I could have got a better deal from Lee (may still do so), however this is my thinking so far:

I got some 16mm x 500mm rails for the table X traverse. decided to go for a fixed gantry, moving X table as I reckon I can make this more easily rigid than a full moving gantry. With 500mm rails I can get a full traverse on a 230mm table.

The 350mm leadscrew will give me about 200mm usable table width in the Y (assuming the motor mount is ~100mm wide) or I could use the 400mm here to give me 250mm usable table width (in which case I would buy another 600mm of leadscrew at £6 approx). I have some 12mm x 500mm rails which would need to be shortened as appropriate to "Travel + 125mm", i.e. 325mm or 375mm, the remaining rail being used for the Z i.e. 150 or 100mm of travel allowing for mounting.

The remaining leadscrew would give me up to 170mm approx Z travel but I will be limited by the rail length as above.

Here is a quick sketch of the base and X axis. haven't yet decided what to make this of yet... mdf or Ali...