Hold down techniques and jigs - please share!

[Brady Watson]

One more...2" thick walnut, screwed into the back and countersunk screws into MDO strips, then screwed strips down to table.

As you can see....there is no right or wrong with hold down...whatever works for the job at hand with the least amount of post cleanup or aggravation is the way to go.

[joe]

Jim,

Odd as it may seem, thanks for your views. You're right, I should give it a break and will.

Joe

[EricSchimel]

Jim,

Odd as it may seem, thanks for your views. You're right, I should give it a break and will.

Joe

Good.
-------

[bill.young]

Joe and I have had our differences over the years but I think we'll all agree there is no more knowledgeable person on this forum than Joe when it comes to signs...he's an amazingly talented sign artist and it would be a shame for the sign guys to lose access to that information.

Joe...if you're interested in still staying a part of this forum just remember that your experience and interest is in signs and not CNC. Keep in mind that this is a CNC forum, and although there is lots of specific applications discussed on here...like signs...it's main purpose is to share information on CNC techniques. Stick with what you're really good at.

My 2 cents,
Bill

[Burkhardt]

I built my machine with a t-slot extrusion table and originally used clamps only (with blanks on spacer blocks when cutting through) or screwed down onto a disposable board to avoid tabs when the cutout parts had holes anyway.
Later I switched to vac pods with low volume quiet GAST or Thomson pumps. As mentioned in earlier post, refurbished ones are really cheap on eBay and my first pump is still working well after 6 years.

Since the vac pods are still a bit fumbly to position and bolt down I finally converted a few of my T-slot channels to vacuum conduits by sealing the crevices between the extrusions and covering the slots with thin aluminum sheets. I punched a few holes into the sheet and can now access vacuum about anywhere on the table. The unused holes are closed with a piece of duct tape. I only need a reusable gasket (cut from non-slip foam drawer liner) and can slap a board on the table and get it fixed within seconds.

In case I need to cut through the board, I use a spacer board with adhesive gaskets on top and bottom. I have a bunch of them in different sizes that are semi-reusable.

The only reasons to not use vacuum (back to clamps or screws) are for me:
- porous material (forget mdf)
- leaky knots or cracks
- parts are too small (maybe less than 2 square inch).
- parts have complex outlines (e.g. text) or many holes

T-slot as vacuum conduit:


Custom spacer board for multiple small parts (I needed 40 pieces)


After cutting:


Another spacer board to allow cutting the part all around to the bottom. The clamps hold the spacer board in place when the vacuum is turned off to swap parts:

[bill.young]

I think these clamps from the Kreg pocket screw people are pretty neat:

https://www.kregtool.com/store/c29/b...in-line-clamp/

[chiloquinruss]

Here's my setup. 10 years and still works for me. I also use screws, Kreg clamps, and all kinds of weird stuff when necessary but the majority is still my t track system. The spoil board stands proud of the t channels. Russ

[JimDav]

Joe and I have had our differences over the years but I think we'll all agree there is no more knowledgeable person on this forum than Joe when it comes to signs...he's an amazingly talented sign artist and it would be a shame for the sign guys to lose access to that information.

Joe...if you're interested in still staying a part of this forum just remember that your experience and interest is in signs and not CNC. Keep in mind that this is a CNC forum, and although there is lots of specific applications discussed on here...like signs...it's main purpose is to share information on CNC techniques. Stick with what you're really good at.

My 2 cents,
Bill

Well stated Bill. I agree 100%

[bobmoore]

What a bunch of tender egos on this forum lately. If I only learned from people that were nice and agreed with me I wouldn't know half of what I do. Take a little and give and little back but don't take it so seriously, it is just cnc work. you are not curing brain cancer.
Bob Moore

[Brian Harnett]

I like pneumatic clamps for production type work they can be set up just about any way.




Air cylinders running through the table


Off the end, great for dovetailing and tenons