[tommy78]

Hi folks, I am making my vacuum table out of 1'' solid MDF wood board,
can I move my Hiwin Blocks close to the centre of my aluminium table ?

doing that I will get like 8 inch extra in my Y axis

Will that may have negative impact for stability of the construction etc ?

I use my cnc for engaving on acrylic .

[SignTorch]

won't hurt to try - but the less space you have between the blocks leaves more table overhang to vibrate and lowers Y/X aspect ratio which increases racking/binding potential - all of which loads/wears the bearings more - and dust or chips or a bad spot on the bearings would have a greater impact - I'm guessing, by looking at the picture, you'd be much better off to just try to squeeze 3 or 4 more inches of travel at most out of it - assuming that whatever drives the table has that much extra travel to make it work without a major overhaul - of course it will have some negative impact - but for light duty cutting it might not have any noticeable impact - looks like you could just move the blocks to try it and put them back if it causes problems

[tommy78]

Can I have that table made this way, will that be flexible or will it be OK for working on 5mm plexi engraving that I mostly do ?

I plan to make it out of 28mm MDF and 10mm Pleksi

[SignTorch]

if you have a dial indicator that will let you check for vertical play or racking - or first just grab it by the edges and twist horizontally and push and pull up and down and see if you can see any movement - there's a chance it might be stable enough for you - in principle it looks like a bad idea but it just might work if that's what you want to do - try it and let us know - that's the only way to know for sure

[tommy78]

I can cheap order a stell 10mm thick to replace that mdf, will that be any better ?
I was told by a mechanic that only aluminium minimum 20mm would be good for it

[SignTorch]

aluminum plate is not always flat - if the mdf is flexing or warping then 10 or 12 mm aluminum might help - but it might have to be faced off on both sides or you might have to get tooling plate aluminum like mic-6 or equivalent -

[Uguessedit]

Couldn’t a person use bronze blocks or nylon blocks outside your bearing blocks to at least add support for the overhang when using bearing blocks closer together? Seems to me you could have 4 dummy blocks at each corner for the overhang support and the bearings set within a square under the spindle where most the machining is done.