Milling and CNC Machine Hold Down Clamps

[jjr2001]

I needed a few good clamps. Saw this type in several places including LMS and I think KBC as well as MSC.
They don't require packing and can be used with the pallets or T-Slots. Mine are designed for 1/4" bolts.
I use cap screws for my pallets so I stuck with them for these clamps.

Normally riveted but I had these brass screws and nuts in the shop so I thought that I could use them
and have the ability to change out the spacers for other types like brass or steel depending on the job.
The aluminum ones may have a flat face cut on them if desired. Aluminum sides were all cut on my CNC machine
after I made the new router mount. The new mount is a total success and makes the machine more rigid than with
the maple one that broke. The spacers were made on the lathe. The steel cross bolt was made using the mill and the lathe.

Porter Cable Router Mount thread:
http://www.homemadetools.net/forum/c...le-mount-66003

So here they are..Kinda look like little race cars!

Cheers, JR

[thehomeengineer]

Hi very nice. makes life so much easier when you have the correct tooling for the job. I really like the design and I know you said they don’t need packing but I guess if needed you could increase the height, you just place a block under the toe of the clamp and use a long piece of studding. Neat design and nicely made.
thank you for sharing
The Home Engineer

[Frank S]

They look a lot like roller rockers, you could actually use discarded roller rockers from engines. If you can score a set of 1.6 to 1 ratio from a big block chevy race engine all the better but the 1.5 to 1's are just fine

[motorhead]

I'd like to add that somewhere, I have seen pictures of rocker arms being used as hold down clamps. It might even been here on HMT.

[jjr2001]

Thank you both. Homeengineer, yep sure can use packing if you need it for larger pieces. These clamps will
work in many situations.

Frank, never thought of that but I think you have something there. I like the idea of re using existing parts especially when
you can use them for tools.

Cheers, JR

[mklotz]

This style of clamp, minimizing the need for packing, is great for quick clamping. My approach to making them is a bit simpler. Slices of pipe are bisected and a slot cut with an endmill. Add a piece of studding and, voila, clamps.

[jjr2001]

Nice looking clamps Marv and easy to make in various sizes.
Thanks for posting.

Cheers, JR

[scrdmgl]

Hi JR: I wonder if you tried to use your clamps for a dual purpose, as regular clamps applying downward pressure on the part being held and also as an edge or low clearance clamp for thin work pieces. Given the pivoting hold down bolt, if set against the side of a plate it would apply downward pressure on the piece to be machined. The bearings at the end allow easy rolling of the clamp while tightening, it should work. I've seen similarly designed clamps used that way.

Regards

Jorge

[jjr2001]

Thanks for the idea Jorge, I have not tried that since my bolts are in a vertical plane when used on the
pallet or with T-nuts on the mill. I have been using my own mite-bite type clamps for the edges.
My clamping on the CNC finds the bite type clamps great for the edges. I then use some rather block
style clamps for the opposite sides where the bite clamps can press on. Then the new hold downs on top.
Works to a treat as they say.

Cheers, JR

[scrdmgl]

Hi JR: I'm yet to build my own version of these clamps. As they say, "Ambition killed the cat", in that case I'm bound to perish before my time is up.
The idea being, for one set of clamps to serve two purposes. Such as thin pieces or those that need to be machined in its entirety, top holding clamps would be an impediment to the job when its size, exceeds the capacity of a regular mill vise. For those cases, I feel that a solid and square parallel, bolted across the width of the mill's table on one end should do the trick, with an edge contact clamp, pushing the opposite side. I can see now that a tilted ramp would be necessary as an addition to a pivoting locking bolt. That way the front of the clamp would be moving forward and also exerting downward pressure of the work piece when tightening the locking bolt. Increasing the height of the clamp's body to accommodate the ramp, is not an issue since it would be in an open area. Your addition of micro roller bearings to the design, is an excellent way to facilitate sliding of the unit.
I'll be working on a design along those lines. Let me suggest to you, that the value of exchange of ideas can not be overestimated. You inspire me, I inspire somebody else and on, and on, and on.

Cheers

Jorge