Does this clamp exist?

cds333 · Sep 26, 2019

So I have the set of obligatory clamps that came with my mill; the ones with the t-slot clamps and the triangular blocks with the steps in them.

Shop Tools and Machinery at Grizzly.com

I love these clamps but I was hoping someone could direct me to what kind of clamp I can use to clamp from both sides of the workpiece at once.

So instead of this:

It would be something that looks like this:

So instead of using a single bolt and a single t-slot nut, it would use two, one on either side, and the workpiece would be in the middle.

(I photoshopped this btw, it doesn't actually exist afaik)

What kind of clamp does this?

Thanks!

L Vanice · Sep 26, 2019

"What kind of clamp does this?"

The kind you make yourself. Usually, you would be wanting such a thing for one particular job, so you would drill two holes in a steel bar, rather than milling a long slot.

Larry

howieranger · Sep 26, 2019

Like L Vanice said you make you own or if you have traditional bars with slots that are long enough for the job use them; it doesn't matter what the ends are shaped like.

LKeithR · Sep 26, 2019

When I needed some clamps with some extra reach I simply took a piece of 1-1/2" x 1/2" flat a little over two feet long,
heated it in the middle and bent it into a U shape around a 9/16" pin. Your clamping bolt slides anywhere in the slot
you've created and with two 1/2" x 1-1/2" sections bearing the load you can put a lot of torque on it before it flexes. If
you need a longer clamp use a wider flat bar and stretch out the length...

PeteM · Sep 27, 2019

cds333 said:
. . .It would be something that looks like this:
View attachment 265971

So instead of using a single bolt and a single t-slot nut, it would use two, one on either side, and the workpiece would be in the middle.

(I photoshopped this btw, it doesn't actually exist afaik)

What kind of clamp does this?

Thanks!

Not sure how much experience you have with clamping and milling, but it sounds like you want to put a strap over your workpiece -- maybe between two step blocks or at least bolted down at the ends. If so, be aware that you are likely to end up with one side of your work clamped pretty well and the other not equally well secured.

You typically want your work constrained by at least one stop on the table to keep it from sliding due to cutting forces and then clamped with adequate down force in several places you won't be milling. If I understood what you want (that picture) you're likely to end up with one spot clamped, more like a pivot point than a well-secured workpiece. Take a hefty cut and it may move.

Rewt · Sep 27, 2019

What is the advantage over using two step clamps? I don't see why you would want to bridge clamp something (what I call it). Otherwise what Pete said.

Cole2534 · Sep 27, 2019

L Vanice said:
"What kind of clamp does this?"

The kind you make yourself. Usually, you would be wanting such a thing for one particular job, so you would drill two holes in a steel bar, rather than milling a long slot.

Larry

Tubing works well for this, too.

Sent from my SM-G973U using Tapatalk

007Rob · Sep 27, 2019

They have them here

McMaster-Carr

sfriedberg · Sep 27, 2019

Rewt said:
What is the advantage over using two step clamps? I don't see why you would want to bridge clamp something (what I call it). Otherwise what Pete said.

He didn't say, but the work may be overhanging the outside T-slots, preventing the use of two step clamps using those T-slots. Or it might be on a really old miller whose table only has ONE T-slot. (E.g., the non-toolroom models of Nichols hand miller)

D.D.Machine · Sep 27, 2019

look up Te-Co ... I use a lot of there little 2ygu7 model ,, 2 1/2" long 1" wide with a 3/8" slot .. but they make a larger ones

I was getting them from Enco tell MSC screwed up that company

Matt_Maguire · Sep 27, 2019

sfriedberg said:
He didn't say, but the work may be overhanging the outside T-slots, preventing the use of two step clamps using those T-slots. Or it might be on a really old miller whose table only has ONE T-slot. (E.g., the non-toolroom models of Nichols hand miller)

Never thought about that? Attached below is a 1/2” stud one that would give about a 6” stud spread, 3/4” sized might work across a b’port table. I do have a forged set with closed ends that look like a dogbone from the side & can cross the table but I’ve never seen another set like them...

Good luck
Matt

EPAIII · Sep 28, 2019

I agree, I would just use two of the standard clamps, one on each side. Some jobs even require that the clamps be moved, one at a time, after milling some of the features to allow other features to be milled where the clamps were at first. Extra Tee nuts can be helpful when doing this.

Rewt said:
What is the advantage over using two step clamps? I don't see why you would want to bridge clamp something (what I call it). Otherwise what Pete said.

cds333 · Oct 19, 2019

The idea was that I cannot use two clamps because of the spacing of the t slots. The workpiece was just a little too large to allow them to both fit, however something like when I envisioned would fit nicely. This is a mini-mill btw, not a lot of table space. I was thinking about simply making my own but again, this is a mini mill, and milling a long slot in 1/2 thick steel is a big job for this mill and I would rather just buy one if one exists.

Milland · Oct 19, 2019

As was mentioned before, McMaster carries them, under the term "Setup Clamps". Go there, search, and you'll find them.

Mark Rand · Oct 19, 2019

You are running close to the allowable topics for the forum, but you don't have to fear the milling job. You can use a 1/4" or 3/8" slot drill in two passes to get the width of slot you need and limit the depth of cut to 1/4" or so if you are worried about rigidity. Treat it as an exercise to find out the capabilities of your machine.

cds333 · Oct 19, 2019

Bingo! Setup clamps. Thank you very much. Also someone else mentioned the rule about mini-mills. I will avoid discussing them in the future.

James H Clark · Oct 20, 2019

Take two pieces of flatstock, such as 1 1/4 x 3/8ths of desired length and weld two 9/16ths spacers to one side of one and then places the other piece of flatstock against the spacers parallel to the first piece of flat and weld. This makes you a nice holddown suitable for 1/2" studs. I have a numberof them for my knee mills. very handy for wide parts and no messing with heel blocks. Will try to provide pics tommorrow. Ordinary hold downs have their limits. There is no limit to this type of clamp.

JH

thermite · Oct 20, 2019

PeteM said:
Not sure how much experience you have with clamping and milling, but it sounds like you want to put a strap over your workpiece -- maybe between two step blocks or at least bolted down at the ends. If so, be aware that you are likely to end up with one side of your work clamped pretty well and the other not equally well secured.

You typically want your work constrained by at least one stop on the table to keep it from sliding due to cutting forces and then clamped with adequate down force in several places you won't be milling. If I understood what you want (that picture) you're likely to end up with one spot clamped, more like a pivot point than a well-secured workpiece. Take a hefty cut and it may move.

What he said. Do also keep in mind that WHEN you are feeling cocky you have a good solid pair of top bridges nicely securing the work that your milling cutter is agnostic. Spindle can bump-bolts, cutter can eat clamp just as happily as eat workpiece.

Check your traverse zone! Then stay within it.

EPAIII · Oct 20, 2019

I was thinking of something like this. Two pieces of rectangular stock standing upright, on the small side. Spacers that are a bit thicker than your stud size (probably 3/8" for the mill you mention) at both ends. Drill through the rectangular stock and the spacers and add a bolt to hold the sandwich together. That avoids welding and the bolts do not have to be very strong as they do not carry any of the load. They just hold things together.

This may be somewhat useful if you have to use the two outside table slots which leaves little room for the serrated blocks that regular clamps use. But then, I have been able to use these outside slots on my mill with no problems. And the problem that PeteM mentioned in post #5 above still applies. You will have to use extra care to have both sides of the work held down with equal pressure: hand tighten the nuts and then alternate from one to the other with just a half or quarter turn until both are equally tight.

James H Clark said:
Take two pieces of flatstock, such as 1 1/4 x 3/8ths of desired length and weld two 9/16ths spacers to one side of one and then places the other piece of flatstock against the spacers parallel to the first piece of flat and weld. This makes you a nice holddown suitable for 1/2" studs. I have a numberof them for my knee mills. very handy for wide parts and no messing with heel blocks. Will try to provide pics tommorrow. Ordinary hold downs have their limits. There is no limit to this type of clamp.

JH

Matt_Maguire · Oct 22, 2019

I think the OP was happy with the setup clamps he was linked to. Anyway I looked at the shop for my dog-bone clamps & found one of the small ones. The longer ones are maybe 10” OAL & this one 7 & ½”. Never seen forged ones quite like them.

Good luck,
Matt

Does this clamp exist?

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