[cordvision]

I bought a bunch of t-slot clamps for my Tormach (see pic). I hoped they would allow me to fix stock directly to the table so I could mill the entire top of the stock without having to worry hitting any clamps. So far it looks like I wasted a bunch of money on them.

1. They seam to be designed very poorly, it is almost impossible to tighten the actual t-slot nut to the table without the hex nut getting in the way.

2. I can't properly line up the stock parallel to the x-axis because tightening the t-slot clamps moves the entire sock.

3. The clamps have a very strong tendency to lift the stock of the table.

4. They don't seam to hold the stock very securely.


Even used regular strap clamps to fix the stock to the table before adding the t-slot clamps. This didn't work either. Spent about 1.5 hours messing with them before I gave up.

Anybody else with a similar experience? Don't think I'm doing anything wrong.

Attachment 279640


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[JohnHaine]

If these are mite-e-bite clamps they are great. But you only use them one end of the stock, clamp against a fence bolted square to the table at the other. You need to set the clamping hex screw to the Unclamped position first and twiddle the gold nut to allow you to tighten the tee nut clamping screw. I also put another tee nut with just a plain nut on a stud as a backstop. I'll try to post some photos tomorrow.


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[RussMachine]

I would forego those t-slot clamps and invest in a good set of TECO Toe Clamps.
The give a lot more 'push' downward and sideways into your part.

[mactec54]

cordvision

They are the worst type of clamp anyone could buy, the set screw locks into the bottom of your T-slot, this will damage the bottom of your T-Slot,send them back, they are a bad product

When you see anything that has a setscrew to lock something like this, it should send alarm bells,it's going to do damage,to your table, this is not good, to do this to your machine

[tmarks11]

... the set screw locks into the bottom of your T-slot, this will damage the bottom of your T-Slot,send them back, they are a bad product

I have heard this before, but don't understand. The bottom of the t-slot isn't a precision surface, so why the concern?

I would forego those t-slot clamps and invest in a good set of TECO Toe Clamps

First thought: I need to get some of those.
Second thought: INVEST is the right word! $40-50 each clamp. Ouch!

[RCaffin]

... the set screw locks into the bottom of your T-slot, this will damage the bottom of your T-Slot ...
I have heard this before, but don't understand. The bottom of the t-slot isn't a precision surface, so why the concern?

A mill table is not hard, but the screws are hard. So the bottom of the T-slot gets a bit chewed up. If the chewing-up is bad enough, it can result in you not being able to slide T-nuts along the slot.

I prefer to have a top-plate which combines with the T-nut to clamp the lip of the T-slot on each side. much less damage.

However ... I HAVE a mill. I CAN machine things. So I make ALL my own clamps.
Sometimes I use just mild steel, other times (not often) I use some old air-hardening steel. I also use AllThread rod and wingnuts, or plain hex bolts. CHEAP! And I have lots of them too.

Cheers
Roger

[JohnHaine]

Yes they do chew up the bottom of the slot so I pop a slip of aluminium under the screw, and that's also why I fit a second tee nut against the clamp one as a backup. These aren't a panacea but they have never let me down in situations where they are appropriate.


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[RCaffin]

> so I pop a slip of aluminium under the screw,
Which reminds me: I have put a bit of steel packing strap into the slot for the same reason, a few times. I also take care to not chew up the mill table surface.

Cheers
Roger

[JohnHaine]

Here are some photos of a setup on my mill table now, with 2 of these holding an MDF block onto which was screwed a plate of PCB material for profiling.
Attachment 279702



First pic shows the fence clamped on the left side of the table, square to the X axis. This locates and aligns the workpiece. Second pic shows the whole thing. Third is the other end where the clamps are, there's a piece of steel against the MDF to spread the clamping force. Fourth shows a clamp close up - you can see the SHCS which is in an extra tee nut as a backstop, you can't see the aluminium slip underneath the clamp to stop it marking the bottom of the slot. Actually with the backstop as it's clamping the ears of the slot between a nut and washer you can tighten as much as you want, so you don't have to tighten the grub screw on the clamp so much.

Just to repeat, I find these clamps excellent when used in this way for the right job, ranging up to clamping a cast iron block for surfacing and a machine vice casting that I was truing up, with never a problem. I suggest that you persevere.

[RCaffin]

Interesting pics - thanks.
Question: does the MDF ever buckle in the middle?

When the base is thick enough, I usually stick a few cap head bolts through it, recessed below the surface. They go into T-nuts underneath. That also works well.

Cheers
Roger

[JohnHaine]

It might well have done but not enough to notice....actually I was in a bit of a hurry so didn't bother but sometime I will do that.


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[CadRhino]

Can you mill over the entire part (or even face mill/flycut) with these toe clamps holding the part down?
I assume the material needs to be a minimum thickness. Would 1/4" be too thin?
Thanks

I would forego those t-slot clamps and invest in a good set of TECO Toe Clamps.
The give a lot more 'push' downward and sideways into your part.

[tmarks11]

Keep the good ideas coming!

Once you start working parts that don't fit in a mill vise, it is sometimes hard to come up with secure clamping schemes without building a fixture/plate.

[mactec54]

The only problem is not all T-slots are deep enough to put a metal shim under the locking screw, & you end up with a damaged T-slot, the best way is not to use them at all, there are many way to clamp your work on to your Table, it is best to make your own as in the photo below, this is only one way to do this, it get you thinking when you have to do some Machining, that needs a different way to hold parts

[RussMachine]

Can you mill over the entire part (or even face mill/flycut) with these toe clamps holding the part down?

Yes you can.
At my 'REAL job' we were face milling cast iron grates with a 4" face mill, cutting .100 deep per pass, and they held great.
We clamped rails to the table (One in X, one in Y) and on the other two sides we used the toe clamps to push the part into the rails.
Worked like a charm, and we could face mill the entire surface.

[wudbutcher]

Machine a vacuum jig, hook a shop vac to it.... It works for small parts but won't suck through mdf like the 40 hp Decker I use on my day job!

[mactec54]

Keep the good ideas coming!

Once you start working parts that don't fit in a mill vise, it is sometimes hard to come up with secure clamping schemes without building a fixture/plate.

That the art of being a machinist, to figure out a way to hold complicated parts here are some photos, of machined parts

wudbutcher

Vacuum is good, but can't always be used

[Steve Seebold]

I bought a bunch of t-slot clamps for my Tormach (see pic). I hoped they would allow me to fix stock directly to the table so I could mill the entire top of the stock without having to worry hitting any clamps. So far it looks like I wasted a bunch of money on them.

1. They seam to be designed very poorly, it is almost impossible to tighten the actual t-slot nut to the table without the hex nut getting in the way.

2. I can't properly line up the stock parallel to the x-axis because tightening the t-slot clamps moves the entire sock.

3. The clamps have a very strong tendency to lift the stock of the table.

4. They don't seam to hold the stock very securely.


Even used regular strap clamps to fix the stock to the table before adding the t-slot clamps. This didn't work either. Spent about 1.5 hours messing with them before I gave up.

Anybody else with a similar experience? Don't think I'm doing anything wrong.

Attachment 279640


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How many clamps did you buy? If you hate them so much, I'll give you $50.00 for them.

[CadRhino]

Very cool. Thanks for posting the pics.
How did you hold the CNC part to kill it?

That the art of being a machinist, to figure out a way to hold complicated parts here are some photos, of machined parts

wudbutcher

Vacuum is good, but can't always be used

[CadRhino]

Thanks Russ.
I am grateful to have real machinist that post on this site. I learn so much.

Yes you can.
At my 'REAL job' we were face milling cast iron grates with a 4" face mill, cutting .100 deep per pass, and they held great.
We clamped rails to the table (One in X, one in Y) and on the other two sides we used the toe clamps to push the part into the rails.
Worked like a charm, and we could face mill the entire surface.