Cutting Keyways

[Malcolm FarrantParticipant @malcolmfarrant93389]

[Malcolm FarrantParticipant @malcolmfarrant93389]

I am building the Minnie Traction Engine, and see that I have to cut a number of Keyways.

Never done this before so am seeking help on How to do it. What tool to get Any tips and tricks anyone can give me.

As always thanks in anticipation

Malcolm Farrant

[John HaineParticipant @johnhaine32865]

Internal, external, or both?

I have cut one internal keyway in mild steel using a sideways boring tool in the lathe toolpost, feeding using the rack. Bit of a faff if you have to do a lot. External keyways are surely a straightforward job in the mill using a slot drill?

[Harry WilkesParticipant @harrywilkes58467]

If your building the 1" Minnie it may be worth your trying to get hold of L.E.Mason's book on building the engine in which he explains how he di it and it's my understanding that he only used a lathe and drill .

H

[JasonBModerator @jasonb]

I just used a tool in the toolpost and planed them out with the carage when I did mine, also used the same method with the much larger Fowler.

Can also be done with a mill or drill quill if you don't want to use the lathe

[not done it yetParticipant @notdoneityet]

I would not plane them out using the carriage on my previous lathe – the rack pinion was a weak link on that model. I still would not do it on the present one either, but it is a matter of choice.

Apart from the other alternatives mentioned, one could buy a shaper and use that. Adept hand shapers are fairly common and easily up to the job.

Or you could buy some broaches if you have a means of pressing them through.

Hacksaw and filing is another way, but likely needs more skill and practice to achieve the same quality of keyway.

Edited to add that there are attachments,for fitting to the carriage, for keyway cutting.  They would operate with the carriage travel locked down.

Edited By not done it yet on 14/01/2018 13:46:49

[Simon Williams 3Participant @simonwilliams3]

Hi Malcolm, if you are close enough to West Gloucestershire to visit I've got a slotter that'll do this job in less time than it takes to boil the kettle and make a brew. If you are interested send me a PM

Best Rgds Simon

[Mike PooleParticipant @mikepoole82104]

If you are feeling flush then you can buy broaches to do the job, a bit spendy for just one job though.

Mike

[Russell EberhardtParticipant @russelleberhardt48058]

There are a number of designs for lever operated slotting attachments for the lathe but for a one off I would do as Jason describes above. That's what I did for my beam engine model.

Russell

[roy entwistleParticipant @royentwistle24699]

Mike How do you broach a keyway on a shaft ?

Roy

[brickyParticipant @bricky]

I'm with Russell on making a slotting tool that feeds the top slide ,it will relieve any pressure on the rack.The tool will get a lot more use than you think.

Frank

[Mike PooleParticipant @mikepoole82104]

Posted by roy entwistle on 14/01/2018 16:21:48:

Mike How do you broach a keyway on a shaft ?

Roy

I am guessing you are not serious, it is usually the internal keyways that challenge people and a broach is nice solution but expensive for a one off.

Mike

I believe external broaches are used to produce splines in production jobs that can justify the high cost.

Edited By Mike Poole on 14/01/2018 19:11:28

[roy entwistleParticipant @royentwistle24699]

Mike Hence the smiley

Roy

[JasonBModerator @jasonb]

Posted by roy entwistle on 14/01/2018 16:21:48:

Mike How do you broach a keyway on a shaft ?

Roy

Have a look at "surface broaches" half way down this page

[Howard LewisParticipant @howardlewis46836]

In the way that every job spawns several others, why not make a slotting tool (I made mine from a College Engineering casting – but there are many other designs available)

It is worth spending a little time, and money, to make one, but the tool will be available for use for many times in the future.

As Model Engineers say "It'll come in handy, one day"

Howard

[Malcolm FarrantParticipant @malcolmfarrant93389]

Wow, I am overwhelmed by the reaspons…Thank you all

Malcolm

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