Advice on fixture holding needed...

[kprice1658]

Hey guys,

I finally decides to build my own fixture plate - so I can triple my work per run. I started with a 1.25" alum plate that I cut down to 20"x12",and mounted it on the table with alignment pins and bolted through the T-slots.

I'm in the process of laying out all the holes for piece alignment and clamping. I'm going to use dowel pins on the left & top sides to align the stock with the machine.

Heres where I need some advice. Trying to figure out the best way to clamp/hold from the bottom & right sides. It has to be below the work surface (so I can mill the surface) - so nothing can clamp or be on top. Most of my work is .375 - .750 thick, my dowels stick up only .25 to be below the surface.

I've seen some info on the Mitee-Bite clamps, some are "knife-edge" and some look like they have a hex -nut shape around them. Anybody have any experience with these or heard any horror stories?

Thought about making my own - maybe starting with some allen head screws, some mig-welding and some sharpening/grinding, thought I'd ask for some ideas first...

Kevin

[scottishgrant]

hi kevin,

http://www.toolfastclamps.com/devices3.html#two

try this link. i used a similar type of clamp to this last week. i was doing roughing work on flame cut steel blocks. first time i had clamped this way myself.

had 4 clamps on and it worked great. maybe something like this is what you are after.

grant

[patndel]

Hi Kevin,

Most of my machining is completed on purpuse made jigs consisting of 1/2" x 4" wide aluminium extruded flat bar. My idea is to have 2 have the plate secured to the table via 6 holding down cap srews into custom made T-slot nuts. It leaves the surface clean, since they are counter bored, whilst I haven't bothered surfacing the plate, no reason why a skimming cut couldn't be taken.

Re-alignment of the plate is handled by 2 3mm holes drilled into the jig at opposite front corners. "Zero" is always taken from the left most index hole, the right is used to ensure parrallel alignment with the X axis.

This is on an X3, but no reason why you couldn't scale it up for use on the tormach. Something to think about

Pat

[rk176]

Ive used both the MITEE-BITE Fixture Clamp and the Uniforce Clamp both worked realy well. No real horror stories about them it was more of opperators not watching what they were doing .Also the uniforce clamp will wear and crack over time depending how tight you need to grip

[sharpshooter90]

Patndel has the right idea. Because this is a fixture plate and not the finished part, having some extra holes is no issue-
Layout your fixture holes and then find a useable location for as many holes as necessary to hold the plate to the mill table. Drill those and counterbore so you can use flat head capscrews into your T nuts. Bolt it down and do your surface cut.

[kprice1658]

Some good ideas. Since I won't have holes in any of my work-pieces to be able to bolt them down, I have to go with something that side clamps - preferably with some downward clamping force also.

I've got a call into Mitee to get their opinion on which is best for my application. The Uniforce looks interesting in that I could hold 2 blanks with 1 clamp positioned in-between.

Thanks for the ideas,

Kevin

[keen]

Side Clamps........... I have obtained a large capacity lock down jaw type vise - amazingly accurate and so quick to use...............