Work hold down?

[atemylunch]

What do you guys use to hold down your workpieces(t-slots, vacuum, bubblegum)?

[Ken_Shea]

t-slots Yes
vacuum Yes
bubblegum No

Vise (get a good one), clamps, screws, double sided tape, contact cement, fixtures, and everything in between except holding it with your fingers, I ask my friends to do that

My stuff is straight forward enough that holding presents little problem, but it is getting more complicated as the parts get more complicated. I have seen fixtures what appear to be more complex then the part being machined.

[Rekd]

Originally Posted by Ken_Shea t-slots Yes vacuum Yes bubblegum No ...I have seen fixtures what appear to be more complex then the part being machined.

Been there, done that, got an ulcer.

You're only limited by imagination. I've used everything. (Yes, including my own as well as other's fingers; "Ok, Ngyun, you don't move that hand, and I'm gonna run this fly-cutter right next to it..")

[tjstraz]

On my router I use carpet tape to hold down sheet material as well as foam. Works really well.

[Jim Stein]

Magnets

[Brian V.]

I have a drawer full of aluminum magnets and wood magnets, unfortunately they all arived in a nonworking state from the distributor. Nicely the guy I bought them from said it sometimes happens durring shipping so he sell me replacement ones for 1/2 off.

[Kookaburra]

A combination of (Vacuum or Tape) + side clamps is what I have found works for me. The side clamps don't need to be anything special, a slotted clamp and a bolt is all you need to simply press the clamp against the side of the material and lock it down with the bolt on two sides to force the material against your stops or if you are not using stops use two clamps on all four sides. This way you are assured the material will not move sideways during a cut. I find it also handy to produce your toolpath in such a way that it leaves the job attached to the main material. You then simply knock it out after completion.

Hope this helps

[Cold Fusion]

I use a blind hole grid and bolt down the material on 4 edges with long M5 screws and locknuts.

[tpworks]

I use an old kirby vacuum to power my vac-hold-down table using a 2" iron pipe base plate attached to the vac and the large shopvac hose. I made a grid to route out the MDF using turbocad (dxf) and created the toolpath using deskam and then drilled 3/16 holes in a sacrificial piece of particle board. The idea is from shopbot where you can download files for a full 4' x 8' but I only made mine 12" x 48".

Tom

[sixpence]

I spoke to a guy running a big Multicam system with no vacuum. I don't know what material you are cutting but when he cuts small pieces from a sheet of 3mm mdf he does not cut all the way through. He leaves a paper thin layer which holds the sheet together and then runs it through a drumsander and all the pieces drop out the other side. Perfect no trimming necessary!
Just need to bulid myself a drum sander now! It never stops does it!

[Graham S]

Has anyone tried ice?

I have seen things called ice chucks, they have peltier coolers I think and are used to clamp really thin things and also very hard to clamp things. I bet for occasional jobs you could stick things to a lump of steel in the freezer. Obviously not something to do in the middle of summer on a long 3D job but I bet there are a few things it could come in handy for.

Graham

[ger21]

I saw a website somewhere that did CNC ice carvings. The ice was frozen to the table I believe.