[HuguesP]

Hello,

just finished my avid Benchtop Pro 2x2 and I have a question concerning the T slot bed. Moving the probe all along the bed, i have very big Highs and Lows. ( +0.10mm and -0.03mm) wich makes 0.13mm in total along the bed.
I wonder if:

- Is it normal to have such big numbers?
- Does someone have already tried to surface the bed to get better flatness.
- the fact that the extrusions are round at the top, it seems non practical to use the table as it is. Does someone had success using the router straight on the aluminum T slot extrusion.
- Are you all using spoil board, I would like to avoid mdf, did someone already tried aluminum or acetal spoil board.
- In the case of spoil board, what is your setup, threaded holes? mdf planks in between T slots ?

Thanks

Hugues P

[nlancaster]

not a desktop pro owner, but that sounds like it is in the tolerance of the aluminum extrusion.

Not sure if people surface the aluminum tslot table or not on those machines.

[pete1961]

You most likely would want to use some type of spoil board. If you don't you will eventually ruin that surface. Tool crashes, wrong G-Code, etc.
It looks like your in a nice room, you will have a ton of dust cutting wood items!

[mkelcy]

As above, put a spoil board on it and surface the spoil board.

[wmgeorge]

I am wondering what your making out of wood that requires it to be more accurate than 1/10 of one mm? Wood expands and contracts more than that! Yes put on a spoil board.

[HuguesP]

I am wondering what your making out of wood that requires it to be more accurate than 1/10 of one mm? Wood expands and contracts more than that! Yes put on a spoil board.

I mostly do aluminum and acrylic work! Some water cooling distribution plates needs to be really accurate to not leak! I went with an acetal spoilboard

[wmgeorge]

So you really need a milling machine and a water tight metal or whatever material your using without a gasket? I have been in and around machine shops most of my 76 years.

[ger21]

I am wondering what your making out of wood that requires it to be more accurate than 1/10 of one mm? Wood expands and contracts more than that! Yes put on a spoil board.

Drives me crazy when people make this statement.
Regardless of how much the wood moves, you'll always see that .1mm gap. You always want your parts exactly the size they're supposed to be. If they are not, it's poor craftsmanship.

[MARV]

I am wondering what your making out of wood that requires it to be more accurate than 1/10 of one mm? Wood expands and contracts more than that! Yes put on a spoil board.

Although 1/10 mm (less than .004") may be within the realm of many gap filling glues and might be acceptable to many, I think you'd be surprised by the number of Pros who consistently work to tighter tolerance (no gap). And as most Pros will tell you, working with wood is like chasing a moving target; the material is always moving, so you make allowances along the way.

[wmgeorge]

Drives me crazy when people make this statement.
Regardless of how much the wood moves, you'll always see that .1mm gap. You always want your parts exactly the size they're supposed to be. If they are not, it's poor craftsmanship.

Thats .0039 or .004 inch which is the thickness of a sheet of paper, that is why they make clamps and glue. If its metal to metal then the bolts holding the two pieces together should draw that tight enough to not leak without a gasket but most folks would have either a thin gasket or sealer.

[HuguesP]

Thats .0039 or .004 inch which is the thickness of a sheet of paper, that is why they make clamps and glue. If its metal to metal then the bolts holding the two pieces together should draw that tight enough to not leak without a gasket but most folks would have either a thin gasket or sealer.

As you saw on my previous post,the last picture with the water distribution plate, the gasket is a 2 mm and thrust me, i have been there, if you mill your channels too deep, you might see leak on the long run.

[wmgeorge]

As you saw on my previous post,the last picture with the water distribution plate, the gasket is a 2 mm and thrust me, i have been there, if you mill your channels too deep, you might see leak on the long run.

Its a hobby, if you tried to hold +/- .004 in a real wood shop you would be out of a job.

[ger21]

I've worked in a real wood shop for 25 years, and our parts are more accurate than.004".

And for the hobby stuff I do, I'm much more demanding.

[HuguesP]

Its a hobby, if you tried to hold +/- .004 in a real wood shop you would be out of a job.

I more the "AEROSPACE" guy type