Looking for aluminum milling in exchange

[David Buchsbaum]

I have designed a cam-based holddown which I would like to try out on my T-tracks for some solid wood slabs I need to plane down. The key is an aluminum core which I know I could machine myself, but I have had very little experience with aluminum, and do not have the time to learn enough to do this right.

So what I am hoping is to find someone who can look at my drawing and whip out a few of these in aluminum, in exchange I'll work out the wood parts and, assuming the whole thing works as well as I think it will, provide each of us with the wood components for a nice set of holddowns. I'll need about 6 now for testing, and would like to end up with about 2 dozen if they work out.






Any takers?

[Shawn Fennell]

David,
I would be glad to help you out,im a newbie botter,just bought a used prt 96 still in the process of tweaking it in.I'm a tool and die maker by trade and have cnc machine shop at my disposal
send me your mailing add: and as soon as i get a few minutes of spare time ill make you some sample parts.I've been pondering on methods to hold down parts to the sb,its alot different than working with metal,im used to precision vises,magnetic chucks etc...i used all of my funds to buy the sb so a good vacuum table is out of the qustion for the time being.What are some good ways to hold down parts(other than screwing the material to the table)?
---shawn

[Shawn Fennell]

Oh forgot to add that if anyone else has any ideas for modification and/or accessories for the shopbot let me know if could be of any help.
----shawn

[David Buchsbaum]

This sounds like a match made in heaven...

[David McNutt]

David,

When you get these hold downs finished I would sure like to see them.

[Shawn Fennell]

David,
Had a chance to test the clamps yet?
Shawn

[David Buchsbaum]

the first test pieces are ready to be cut at this moment...stay tuned..

[David Buchsbaum]

First let me say a big Thank You to Shawn as he has come through for me in a big way. The aluminum parts are beautiful and extremely accurate - way better than I could have done without pulling out what's left of my hair. I'm guessing they were machined on a CNC lathe - my digital caliper reads that they are within .001 in roundness and size accuracy. Thanks again Shawn.

The technique definitely works. I'll be playing a little more this afternoon with tweaking the amount of cam action and various materials. Here are a few pics from the first test setup

[Gene Buckle]

That is insanely cool.

Are you going to offer the clamps for sale?


g.

[David Buchsbaum]

OK, here's the working prototype. It takes surprisingly little cam action to generate crushing force at the point of contact.




Since Shawn does not have T-track it makes it hard for me to fulfill my original offer, so I made a version that can screw down to the table or to a jig. I'll probably use these for shorter boards like the one in the picture that don't reach between 2 T-tracks.




The cam generates so much force it wants to move the fence, so I came up with this little "table dog" to secure the other side of the board. You could use these by themselves I suppose - I cut the notch into the backside to make it easier to drive it into the wood with a block and hammer.




Not sure if it will be worth trying to sell. Shawn is supposed to be looking into the cost of the aluminum hub. Drop me an e-mail if interested.