Safe use of a slitting saw.

[martyn]

I'm about to use a slitting saw for the first time.

I want to accurately divide square mild steel stock horizontally with a slit about 2mm wide. This is to make a die so a friend can 'crimp' some nipples onto automotive brake ropes for me using his press. The 10mm diameter nipple will go in an 8mm hole through the square stock then be pressed (crushed) by the two halves of the die.

The slitting saw is 3" diameter with an inch diameter hole in the centre, about 2mm wide with 74 teeth. It has a key-way for the arbor which has a 3MT as well as a thread for the drawbar on the milling machine.

I'm a bit afraid of all this!

My feeling is go very slowly with lots of coolant.

The saw will be rotating clockwise so should I approach from the left on the X axis?

I don't want anything flying off, bursting or shifting.

Thanks in advance for any advice.

Martyn

[websterz]

Slow speed, slow feed, flood coolant if you got it...and don't climb cut!!!

[stevec]

Martyn, feed against the rotation of the saw, in case you're unclear on the term "climb cut".

[Harold_V]

The saw will be rotating clockwise so should I approach from the left on the X axis?

Clockwise as it relates to the operator? Yes, that's the correct direction (for conventional instead of climb milling).

If you don't have flood coolant at your disposal, use an acid brush and apply cutting oil regularly. Keep the blade wet, and consider that it's a large diameter, so it must run at a slow speed. Shoot for something near 125 rpm. Not much faster. Lots of teeth, so feed could be respectable, but I expect you'll want to take it slower. Most slitting saw setups tend to not cut uniformly. Start slow with feed and work up. Let the sound of the cut help you in knowing when you're running at a respectable rate. Don't allow the saw to idle in the cut, though---tends to do a lot of premature wear.

You can do it. Enter the cut carefully, for the saw will try to lift the material. Make sure it's securely clamped, so the edge can't ride up.

Harold

[warmstrong1955]

I don't have a lot of experience with slitting saws, but I have used them to build several throttle levers at various different times. Just some little levers that clamp on a shaft, about 3" long .... A36 material, 1/2" thick.

Before I got a flood pump, I used a spray bottle, and cheap cutting oil.
Regardless of the coolant, I fed by hand, low RPM's...(lookin' it up...I scribbled 75 rpm), and... did quite well. Same blade made a couple dozen of the critters. Patience seemed to work.

Bill

[Russ Hanscom]

Cold rolled or any other stock with residual stesses is not a good idea. Make sure your clamping setup does not encourage the slit to close towards the end of the cut. I have a half slitting saw if you need the reason!

[Conrad_R_Hoffman]

Definitely watch the RPM on a saw that big. Don't exceed 125 RPM and there's nothing wrong with going a bit slower, especially if the steel is a bit tougher than expected. You want cutting oil, and be sure both side of the saw are getting some. If it sounds like the saw is only cutting on one side, figure out what's wrong with the arbor. A little asymmetry is normal, but the better the centering, the longer the saw will last. Maybe make a cut in a small chunk of stock before working on the real piece.

[stevec]

Boy! lots of cautions on this subject, I just want to say, don't be scared off, they do a good job. I've used them and I have several that are still good. Only one with corner rounded teeth from running it too fast. I think I keep it as a reminder.

[Harold_V]

Boy! lots of cautions on this subject, I just want to say, don't be scared off, they do a good job. I've used them and I have several that are still good. Only one with corner rounded teeth from running it too fast. I think I keep it as a reminder.

I loaned a 1/16" x 6" slitting saw to a friend, an (assumed?) machinist. He worked in the trade as long as I had. He returned it with well rounded corners, a result of over-speed trying to slit some 303 S stainless. I, too, still have it to remind me. Not only to run slowly, but to not lend tools.

Harold

[spro]

There are arbors which are left hand thread (lht). Many arbors have developed a "bend" over time. So what I'm saying is that the key is not the main holding of the saw. The slight irregularity of the arbor causes a "kerchunk" impact to sleeves and arbor nut. If you think about the arbor driving the wheel clockwise as you see it, the opposition is counter. Then if it is a rht arbor, that may be of concern.

[martyn]

Thank you everyone for the very comprehensive guidance.

I think this might be one for the vice and a new blade in the hacksaw, then truing up with a file and square at the end!

I especially don't like the sound of the slot closing up and breaking the blade!

But thanks and sorry not to be braver.

Martyn

[oldvan]

He who fights and runs away, may live to fight another day.

Nothing wrong with using a process that is within your skills instead of one that is riskier,
especially if the result is equally acceptable.