# Keyway slotting on lathe



## necchiom (Aug 15, 2014)

Hello folks. I would like to manufacture an effective keyway slotting equipment for my Myford S7. Any suggestion or already done project?
Thanks a lot in advance!


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## Hrcoleman66 (Aug 15, 2014)

Hi Moshe,

Are you wanting to do the keyway in a bore, or on a shaft?

You can do a square keyway in a bore quite easily.
First you need to mount your piece in the chuck and lock the chuck so that it will not rotate.
Then get a boring bar, the type that uses a round HSS stock cutter, and mount a cutter in it with a square profile the size you want the keyway (this is not critical, as you can always make the key to fit the keyway later.
Then simply using the cross slide to set your depth, run the cariage along to cut the keyway in the bore with the boring tool.
I have seen this used somewhere else on the web, but can't think where at the moment.

Cheers,

Hugh


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## Jasonb (Aug 15, 2014)

As Hugh says if you don't have many to do then just mount a tool in the toolpost and manually move the carrage back and forth with a very small depth of cut on each stroke, Thats how I cut these 4 keyways which are 1" long and 3/16" wide in steel.







There have been a few designs published in Model Engineer and Model Engineers workshop over the years, Hemmingway also sell drawings fo one and also do castings and materials if needed.

http://www.hemingwaykits.com/acatalog/Keyway_Slotting_Attachment.html


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## Wizard69 (Aug 15, 2014)

The locked head / boring bar method does work but do respect your lathes rack and pinion.    On the really cheap lathes you can easily break off three things on the rack or drive pinion.   So take care and if something feels difficult don't force it. 

Beyond that there are all sorts of methods or tool designs that can be used i place of the saddle mechanism.  Search the net for: "manual keyway slotter" or other similar terms.   There are many designs floating about the net, some well documented and free for the taking.


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## MachineTom (Aug 15, 2014)

If its a shaft, that could mount on the crosslide with VEE blocks, If it is a 3/16 or smaller then mount a keyway cutter in the spindle, and make a single pass at finish depth,  larger keyways could be done but exceed the rigidity of an S-7.

For an internal keyway, buy a used broach and make borrow a press. A 1/8 key needs about half ton to cut in steel, less in nonferrous material. A hammer will not work.


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## chucketn (Aug 15, 2014)

Not meaning to hijack this thread, I am wanting to do the same thing (cutting internal slots in pulleys and gears) on my 7x mini lathe. What is the best method of locking the 7x spindle.
I was just about to post the same type of question when I saw this thread. I can post my question again as a 7x question if that is preferred.

Chuck


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## crankincraig (Aug 15, 2014)

jasonb those are beautiful , I assume you did make them.

Great tip also on how to get a keyway without having a broach or doing one that is an odd size. Don't see why that would not work on the outside of a shaft as well.

Thanks for posting that.


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## necchiom (Aug 15, 2014)

Thanks a lot folks for your quick reply.
I have to slot three pulley belonging to a belt sander under development. Here in attachment some pictures of it.
Unfortunately moving the carrage back and forth in a S7 is a tough work... mainly because the small hand wheel.
I am looking something like the Hemingway kit.


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## BaronJ (Aug 15, 2014)

necchiom said:


> Hello folks. I would like to manufacture an effective keyway slotting equipment for my Myford S7. Any suggestion or already done project?
> Thanks a lot in advance!



Hi Moshe
Have a look at this thread, post 92.  You might recognise some bits stickpoke

http://www.homemodelenginemachinist.com/showthread.php?t=22047&page=10

It describes my hand slotting tool. I needed to put a 4 mm slot into a bronze bush. So I purchased a piece of 4 mm square tool steel. 

As far as sharpening is concerned I just treated it as I would a lathe tool bit.


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## Jasonb (Aug 15, 2014)

Yes they are from my 2" Traction engine, made to slide along a splined shaft.

The only thing with using a similar method to cut a keyway in a shaft is that you really need a small gap to let the tool run out at the end of the slot, a drilled hole just a fraction bigger than the slot will do. Also watch that the work does not flex away from the tool, use tailstock support if possible

To index those 4 slots and a way to lock the spindle is to put a block between the undersid eof a chuck jaw and the lathe bed and then use a clamp to hold things together.


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## necchiom (Aug 15, 2014)

Hi Baron. Nice to read again from you.
Unfortunately I've missed your very cool project. I will try to replicate something similar. Thanks!


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## BaronJ (Aug 15, 2014)

Jasonb said:


> Yes they are from my 2" Traction engine, made to slide along a splined shaft.
> 
> The only thing with using a similar method to cut a keyway in a shaft is that you really need a small gap to let the tool run out at the end of the slot, a drilled hole just a fraction bigger than the slot will do. Also watch that the work does not flex away from the tool, use tailstock support if possible
> 
> To index those 4 slots and a way to lock the spindle is to put a block between the undersid eof a chuck jaw and the lathe bed and then use a clamp to hold things together.



Hi Jason,
On a Myford you can lock the chuck in any of 60 positions using the back gear lever without disengaging the crown wheel.


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## BaronJ (Aug 15, 2014)

necchiom said:


> Hi Baron. Nice to read again from you.
> Unfortunately I've missed your very cool project. I will try to replicate something similar. Thanks!



Hi Moshe,
Its nice to be able to offer something in return.
Unfortunately I didn't do any drawings since it was something done on the fly after doing the keyways on the replacement mill gears.  I did those by winding the saddle up and down.  Like you I wasn't too happy with doing that, but it was the only way at that time.

http://www.homemodelenginemachinist.com/showthread.php?t=22837  From post 10 onwards.

This link will show you what I did to repair the mill.


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## tornitore45 (Aug 15, 2014)

When I need to lock the spindle on my 9/20 I place a 5/16 coupling nut and bolt between the head and chuck acting in expansion. The faces are shallow dished to provide grabbing corners.  Not suitable for resisting heavy  torque but adequate for slotting.


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