Slitting saws on Myford lathe

[Andrew Phillips 4Participant @andrewphillips4]

Hi All, I wish to make a couple of clevis joints in 10mm square stainless steel; the slot is about 0.2 inches wide and 0.6 inches deep, and I would be using my Myford Super 7 lathe. I have turned the clevises and need to slot them. I have an unused 3/16 wide woodruff cutter given to me years ago so I clamped a clevis in a small Myford vice bolted to a milling slide, but the cutting forces were too great and the clevis moved. I then tried a cheap and cheerful 50mm x 1/16 in slitting saw on an arbour (bought years ago) but the teeth only make contact for a small portion of the circumference. I have a substantial between-centres arbour I made in evening classes for use with my Myford saw table, which takes 1in bore blades. I plan to use this in conjunction with the vice/milling slide to cut the slot. Several dealers stock 3 and 4 in saw blades with 1 in bores, with varying numbers of teeth. What would be the optimum number of teeth for 3 or 4 in saw blades for stainless, and optimum width – I realise I would have to take several cuts, and could use the woodruff cutter to finish slot edges.

[Andrew Phillips 4Participant @andrewphillips4]

[John HaineParticipant @johnhaine32865]

Posted by Andrew Phillips 4 on 25/01/2022 15:58:08:

… I then tried a cheap and cheerful 50mm x 1/16 in slitting saw on an arbour (bought years ago) but the teeth only make contact for a small portion of the circumference. …

Quite common, I doubt that another one would be much better.

[BazParticipant @baz89810]

In over 50 years on the tools I cannot remember a slitting saw that ran true, they always seem to cut for part of a revolution, if you push them hard enough so they cut continuously they have a nasty habit of going Bang!

[Anonymous]

I think you're probably on a hiding to nothing trying to use the Myford. I agree with Baz that slitting saws always run slightly eccentric. Another issue is that they can go walkies if not properly supported. Even on my Bridgeport slitting saws often don't cut true when deep slotting. On the horizontal mill they are fine, but it's a heavy old beast.

When I make clevises it's easier to use a slotdrill or endmill end on rather than use a slitting saw to make the slot. A problem with stainless steel is that some alloys work harden if you let the tool rub. An issue may well be that the Myford isn't rigid enough to take a decent cut per tooth to prevent work hardening. If I was going to use a slitting saw I'd use a coarse tooth one, as below, apart from the one bottom right:

The coarse teeth ones have a big enough gullet for the swarf to escape without jamming. Fine tooth slitting saws are intended for shallow slots only.

To summarise, forget slitting saws and use a slotdrill or endmill. Or drill out the waste and finish by filing. When making clevises I cut the slot first on a longer length of material and then turn the remainder using a split bush.

Andrew

[JasonBModerator @jasonb]

Unless you can do it in one go with a 5mm side and face cutter using multiple cuts with a thinner slitting saw will see the second and subsequent cuts just wander into the previous. A long series milling cutter would be easier. If it were 3mm or 1/8" you could probably get away with it on the Myford

Like Andrew I get the slot out the way early on while there is a good length of bar to hold, do the cross hole and then saw it off from teh parent bar to turn and drill/tap the end. Finally rounding over teh clevis with buttons & a file or on an arbor in the rotary table

[Andrew Phillips 4Participant @andrewphillips4]

Hi All, thanks for your suggestions. I will try Andrew's suggestion using a 3/16 end mill and cutting the slot first so there is plenty of material to grip in the vice. Cheers, Andrew P

[Author]

Posts