MT extension socket

[HevansccParticipant @hevanscc]

I have a Tom Senior M1 and just bought a rotary table to cut some gears for my lathe which is missing a few changewheels which are 18 dp and 20 pa. I have not been able to find an appropriate cutter so my intention is to make my own gear cutter by making a flycutter and holding it in a MT3 arbor as described in Ivan Law's Workshop Practice 17. I would then put the arbor in the mill in horizontal mode to cut the gears, but it doesn't look like it will protrude far enough to center over the table (happy to be contradicted on this).

I have a MT3 extension socket for a tang, which came with the mill, but understand that this is a no-no, so I have been looking around for a MT3 extension socket with a drawbar, but can only find the tang type. So, my question is, where can I get a MT3 extension socket for drawbar, or is there another obvious solution which I am missing?

Many thanks for any advice

Hywel

[HevansccParticipant @hevanscc]

[Anonymous]

Posted by Hywel Evans on 05/07/2016 09:18:23:

I have a Tom Senior M1 and just bought a rotary table to cut some gears for my lathe which is missing a few changewheels which are 18 dp and 20 pa. I have not been able to find an appropriate cutter…………

Readily available here:

**LINK**

and here:

**LINK**

I've not used a gear cutter from Tap&Die but I have bought from Victornet. They're 'import' cutters, but it worked fine.

Andrew

[HevansccParticipant @hevanscc]

Readily available here:

**LINK**

and here:

**LINK**

I've not used a gear cutter from Tap&Die but I have bought from Victornet. They're 'import' cutters, but it worked fine.

Andrew

Hi Andrew, thanks for the links. Perhaps I should have included the words 'reasonably priced' infront of 'cutter'. the tap&Die ones are pretty steep. The Victornet are reasonable but freight and import will stack up – you don't happen to know what they charge do you? Part of my reason for doing it is to learn new techniques so i quite fancy having a go at making the cutter.

Edited By Hywel Evans on 05/07/2016 10:05:24

[Anonymous]

Posted by Hywel Evans on 05/07/2016 10:04:04:

Hi Andrew, thanks for the links. Perhaps I should have included the words 'reasonably priced' infront of 'cutter'. the tap&Die ones are pretty steep. The Victornet are reasonable but freight and import will stack up – you don't happen to know what they charge do you?

Quite so, there's a difference between available and affordable! Prices are one reason I haven't bought from Tap&Die. I can't remember what Victornet charged and don't have time to look it up at the moment. I'll dig it out this afternoon. I think it came USPS. The biggest pain is Parcelforce charging a hefty fee on top of import duty/VAT. I guess make or buy depends upon how one values time.

If I was going to make a gear cutter I'd make a multitooth one similar to this spline cutter:

But I guess it depends upon the tooling available.

Andrew

[JasonBModerator @jasonb]

Can't you just make your MT arbour longer in the first place rather than extend it?

Or if you have a horizontal spindle for your mill make a ring say 1" ID, 3" OD, 1" wide. this can be drilled to take your ground single point cutter and cross drilled for a grub screw to retain it against a flat. This will be more sold as it can be supported by the overarm.

Edited By JasonB on 05/07/2016 10:47:23

[AjohnwParticipant @ajohnw51620]

It sounds like you don't have the over arm for your miller or are swinging the head to 90 degrees ?

Why swing it to 90 degrees if so ? If your using a rotary table the main problem it likely to be getting the gear blank sufficiently away from the table to clear the cutter.

If you do have the over arm and shaft to go with it the cutter would be fitted into a sleeve to go on it along with the appropriate spacers.

You may find the RDG do some reasonably priced gear cutters but I don't think that they will be 20 d PA. You can get good results with a correctly made fly cutter anyway.

John

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[HevansccParticipant @hevanscc]

JasonB and John,

I do have the overarm so the idea of the ring to take the ground cutter is a good one which I might try instead.

Many thanks for the suggestion

Hywel

[HevansccParticipant @hevanscc]

Posted by Hywel Evans on 05/07/2016 11:20:24:

JasonB and John,

I do have the overarm so the idea of the ring to take the ground cutter is a good one which I might try instead.

Many thanks for the suggestion

Hywel

I just realised that a problem with this is that the method described in the original post ensures that the cutter is made with clearance, because it can be held in the arbor eccentrically during making. I will have to think about that also.

[AjohnwParticipant @ajohnw51620]

You could simply make a circular form cutter and then just gash it for one tooth. Not sure if that is in the books but it's about on the web. Usually done by making a lathe tool with 2 button on it that form the correct shape. It's also possible to add more teeth but the jig to do it is more complicated. Some have made these from flat ground cast rather than bar.

John

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[JasonBModerator @jasonb]

I would have thought that if made with the cutter set at a smaller radius to what it will be finallu used at then you will get clearance. Or just pop the ring onto a stub of 1" bar and hold at whatever position you want in the 4-jaw.

[HevansccParticipant @hevanscc]

Posted by JasonB on 05/07/2016 11:42:09:

Or just pop the ring onto a stub of 1" bar and hold at whatever position you want in the 4-jaw.

Yes, that sounds like a good solution. Thanks

[Swarf, Mostly!Participant @swarfmostly]

Hi there, Hywel,

Check the tang of your MT adaptor to see if it's hardened and to confirm that it has a female centre.

Assuming the tang is not hardened, mount the MT adaptor on the lathe with its body in the four-jaw chuck and the tang centre supported by the tail-stock centre. Dial in until it's running true.

Then turn away the narrow end of the taper, removing the minimum amount of material, to form a short parallel section just long enough to match the thickness of the fingers on your fixed steady. Fit the fixed steady and back off the tail-stock centre, then turn off the tang, face off and drill and tap the end of the adaptor for the draw-bar thread of your choice.

This procedure is based on that described on page 106 et seq. of 'Simple Workshop Devices' by Tubal Cain (the real one!). You only need remove about 3/8" from the narrow end of the taper shank – there will be more than enough taper left for it to do its job (but do 'remove all burrs & sharp edges' ) .

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 05/07/2016 15:26:00

[Neil WyattModerator @neilwyatt]

These pictures may help? Using a single point cutter in my mill.

[HevansccParticipant @hevanscc]

Thanks for all the replies. I'm going to go with Jason's suggestion of the ring to fit on my horizontal arbor and the flycutter insert.

Hywel

[Author]

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