Safe use of a slitting saw.

[martyn]

If I get brave and use the mill and slitting saw...

...would it be a good idea to use the stub arbor without the key. I've read that this (obviously) allows the saw to turn on the arbor if it binds so you avoid the chance of it breaking or bursting? I.e. you are using the friction induced by the arbor's nut and spacers to hold the saw.

As regards keeping the cut open I thought I might put a snug fitting rod down the hole through the die-block I'm making then holding the rod on a universal V-block bolted to the table. The V-blocks I have are the type with a 'horeshoe' clamp over the top so I could indent (slightly countersink) the top of the workpiece so the clamping bolt would seat firmly in it.

I also thought of drilling through the virgin end of the square bar and actually bolting that to the table.

This is the firmest set-up I can think of.

Martyn

[Harold_V]

If I get brave and use the mill and slitting saw...

...would it be a good idea to use the stub arbor without the key. I've read that this (obviously) allows the saw to turn on the arbor if it binds so you avoid the chance of it breaking or bursting? I.e. you are using the friction induced by the arbor's nut and spacers to hold the saw.

Absolutely! In fact, you should avoid a key with slitting saws, up to a reasonable limit in width. If they wedge, the key will most likely break the saw, whereas you have a small chance that it will slip and you can get out of the cut before the saw meets an untimely end. Just make sure that you run the blade in the right direction, so it self tightens.

I can't think of a time when I've used a keyed arbor for slitting saws, including driving the 6" diameter one I mentioned in a previous post.

As regards keeping the cut open I thought I might put a snug fitting rod down the hole through the die-block I'm making then holding the rod on a universal V-block bolted to the table. The V-blocks I have are the type with a 'horeshoe' clamp over the top so I could indent (slightly countersink) the top of the workpiece so the clamping bolt would seat firmly in it.

A picture of the part in question would help. You may be going to a lot more trouble than may be necessary. That would be particularly true if you intend to use a side cutting slitting saw. Not all are. Screw slotting saws are much like a band saw blade, minus set. They don't have the ability to cut on their sides, so if, by chance, the slot allowed the part to close in, there is the potential to trap the blade. With a side cutting blade, it would simply open up the slot accordingly.

I reread your description, and came away with the idea that you'd end up with two pieces of material after slitting. Is that correct?

If so, there's no worry about the part trapping the blade. The added material in the cut would most likely just complicate things.

Something more to ponder. It appears you will use the resulting piece of work as a die for squeezing other material. I'm not convinced your choice of material will serve well. It is most likely not any harder or stronger than the material you'll swage. I expect that you'll do as much damage to the die as you will the part, rendering it pretty much useless after one application. If the piece to be swaged is aluminum, that may not be the case.
To that end, assuming you have more than one piece to swage, have you considered using a heat treatable material? It need not be tool steel, but you'd likely achieve respectable results using some 4140 and heat treating after machining, to about 50 Rc. Just a thought.

Harold

[martyn]

Thanks for all those wise words.

I think Harold suggests steam hammer to crack nut. I'm coming to that way of thinking!

What we're trying to do here is get a connector onto a brake rope. I guess this would be a broadly similar set-up to what Henry Ford might have used on something like the Model A.

At first I wasn't sure how the Austin Motor Company did it at the outer end because the pedal/lever end of the rope has the coupling attached by spreading the strands of the rope with a small cone then soldering it into the nipple.

Accepted wisdom is it was crimped at the brake end. Thus I made connectors on the lathe and mill bored to take a 5mm rope passing through a 10mm diameter tube for a length of about 25 mm. My friend volunteered to close the tube onto the rope using his 15 ton press but says he needs a die to do it. That is what I want to make - a split block about 20 mm square with an 8mm hole along the axis for 25 mm or so, so that when he puts the tube part of the connector into it with the rope in place then places them under his press the tube will be crushed onto the rope locking it in place. The connector is mild steel.

'Simples' as they say!

Martyn

[Inspector]

Sounds like you are making a version of Nicopress stop sleeves. Utility companies use them a fair bit and if you just need one a lineman might crimp one for you.
http://www.nicopress.com/

Pete

[Russ Hanscom]

Depending on the size, might find one at your local big box. A few years ago I got one that does about four of the smaller sleeves, looks like a bolt cutter with special jaws. It was only $30 at the time so I grabbed it. It got used just the other day to crimp some terminals on battery cables.

[dly31]

If a soldered connection is good at one end I would think it would also be good at the other end unless the length of the solder joint is less. Motorcycle brake and clutch cables have been soldered for a very long time. It does require a good spreading of the wires and a good solder job to prevent pull-out but the length of the joint is generally only about 10mm.

[martyn]

Thanks for that extra input, I will be taking all this on board.

Martyn

[Russ Hanscom]

Actually large wire ropes used to be terminated with babbit. The socket was made with an nternal flare, the wire rope was flared out and fluxed to remove oil etc, and melted babbit was poured in. Used to be a common oilfield practice.

[boaterri]

West Marine also has that style fittings for wire rope (think boat life lines). The better news is that they have the crimp tool all set up on the work bench to make up the ends. They will not do it for you due to insurance reasons but your welcome to do it your self.

Rick

[martyn]

Thanks again 'guys'. This is really helpful stuff.

Martyn

[revrnd]

I'm making a work stop that requires 2 holes be "slotted" to the end of the detail. This will allow for clamping forces to lock the stop rod. The mat'l thickness to be cut is 3/8" Following the guidelines posted before, do I just m/c the slit in 1 pass?

I don't ever recall using a slitting saw @ work. If I did use 1 it was during my apprenticeship over 30 years ago.

[OlderNewbie]

I just forged ahead and started to slit things, using what I thought was an appropriate SFPM and a feed that sounded OK, with plenty of brushed-on cutting oil (steel) or WD-40 (Aluminum). When things didn't sound as though I was getting a clean cut, as in 1018, I backed out and re-ran the already-slitted section before continuing. I did learn to back off some speed from normal SFPM, but not by breaking or dulling anything...just because I didn't like how it sounded. This thread has been helpful for me, helping affirm that I was doing more or less the right things, even if by accident. So my message is a bit different. Use some caution, but don't overthink this. Using a slitting saw really doesn't seem to be that hard.

John