Rotary broaching – the easy way

[Michael Cox 1Participant @michaelcox1]

[Michael Cox 1Participant @michaelcox1]

I have developed a tool for rotary broaching that is very simple to make. It also facilitates making the required cutters. Further details are here:

http://mikesworkshop.weebly.com/rotary-broaching.html

I hope this is of interest to other members of this forum

Mike

[alan frostParticipant @alanfrost17805]

Certaqinly was-don’t know when but thanks-very clearly written and photographed.

[adyParticipant @ady]

Your running centres are dead cool.

All interesting stuff.

[modeng2000Participant @modeng2000]

When hardening silver steel wrap the tool bit with iron wire to make a loose cage and rub softened soap between the wire loops. It does save a lot of cleaning up before the tempering. Leaving the iron wire long enough gives a handle instead of using tongs.

 

John

[Ramon WilsonParticipant @ramonwilson3]

Michael, What an excellent informative description of making this useful bit of kit.

 

I have only recently been aware of how such tools work but the ease of which your tool can be made makes it a very attractive proposition.

 

It appears your tool post is based on an expanding mandrel principle – does it have a single taper or is it expanded top and bottom?

 

Regards – Ramon

[Michael Cox 1Participant @michaelcox1]

Hi Ramon,

The tool post is a simple cylinder, with six vertical cuts at 60 degree intervals, that is expanded by a cone at the top.

Mike

[Peter HallParticipant @peterhall61789]

Mike, that’s an impressive website you have there. Useful too. I have been inspired by your milling machine table stops to fit something very similar to my little X1 mill, so thank you for that.

 

At the risk of hijacking your thread slightly, can anyone recommend a supplier for the iron wire that John mentions? I could do with keeping some in stock.

[Ramon WilsonParticipant @ramonwilson3]

Thanks Mike, I was looking for a simple, ie easily made, type and this fits the bill perfectly. I have an old Unimat that has been dragged from under the bench for machining very small plastic parts – it comes hard setting up each tool having been used to a Dickson QC on the Myford

 

Regards – Ramon

[Michael Cox 1Participant @michaelcox1]

Hi Ramon,

There is write up of the toolpost, including dimension drawings, in MEW 158 (Dec 2009) entitled “A novel quich change toolpost”.

Mike

[Michael Cox 1Participant @michaelcox1]

Hi Peter,

Thin iron wire is readily obtainable from most florists. It is used in arranging flowers as stem supports etc.

Mike

[Peter HallParticipant @peterhall61789]

Thanks, Mike. I can pick up a bunch of freesias for Mrs Hall while I’m there. Two birds, one stone.

 

Pete

[jacques maurelParticipant @jacquesmaurel42310]

read my article about “polygonal punching tool” in ME N°4310 oct 2007 it gives informations about the hole to drill before punching.

J Maurel

[Michael Cox 1Participant @michaelcox1]

Posted by jacques maurel on 20/09/2011 16:03:49:

read my article about “polygonal punching tool” in ME N°4310 oct 2007 it gives informations about the hole to drill before punching.

J Maurel

Hi Jaques,

Thanks for your message. I do not have access to back copies of ME. Could you send me a copy. PM me if this is possible.

Mike

[Michael Cox 1Participant @michaelcox1]

I have made some modifications to my rotary broaching tool and added a link to a video of the tool in use, see:

http://mikesworkshop.weebly.com/rotary-broaching.html

Mike

[guri alleyParticipant @gurialley39278]

Hey guys, I have bought a very good quality round broach. If anyone requires any type of broach, you can buy from Broach India. I am sure you will be satisfied.

Edited By guri alley on 06/05/2016 07:34:56

Edited By guri alley on 06/05/2016 07:35:16

[David ColwillParticipant @davidcolwill19261]

By a complete coincidence I ordered a couple of phosphor bronze bushes (which came yesterday) to make my version.

Owners of the T2 style toolpost set will recognise this item

and with bush fitted.

It hardly counts as a build

David.

[John HinkleyParticipant @johnhinkley26699]

Posted by Guri Alley:

"Hey guys, I have bought a very good quality round broach. If anyone requires any type of broach, you can buy from Broach India I am sure you will be satisfied."

Am I getting more cynical in my old age, or is this a blatant bit of advertising?

John

[John Stevenson 1Participant @johnstevenson1]

Not sure John, but he's on the watch list.

3 posts, one could be an advert and the other two are generic. So we will see what happens.

If it is advertising then no one is going to buy off the Indians anyway, unlike Aliexpress they don't have a sales vehicle in place and who on this forum is liable to buy a special broach when they get more enjoyment spending 5 weeks and 5 bean cans to make one ?

[Michael GilliganParticipant @michaelgilligan61133]

John [Hinkley]

Have you used the 'Report' feature ?

[orange flag, at bottom-right of post]

MichaelG.

.

Edit: Probably not needed now, since a Moderator has already commented.

Edited By Michael Gilligan on 06/05/2016 09:36:22

[Ed DuffnerParticipant @edduffner79357]

A big thank you from me also. It was Mike's article that made me realise the 1° offset did not have to be built into the tool.

Ed.

[MuzzerParticipant @muzzer]

It's a pretty neat but simple process. Would be nice if you could buy sets of broaches for common features such as metric hex and Torx sockets at hobby prices.

The tools are a bit more tricky to produce due to the internal taper but the same basic setup would also be usable for external features, as illustrated in this commercial video that follows on eventually from Mike's. Has anyone tried that yet?

Murray

Haha – he says it's capable of accuracy of "5 tenths of an inch or better". He actually means half a thou in English, not half an inch!

Edited By Muzzer on 06/05/2016 10:26:38

[Roger HeadParticipant @rogerhead16992]

What a brilliantly simple solution! Well done, Michael Cox.

Does anyone see why a Torx hole could not be done? Would the re-entrant shape affect things?

Noticing the original posting date makes me wonder (again), just how many masterpieces are lost in the archives…

Roger

[MuzzerParticipant @muzzer]

If you watch the video I posted, you can see that Torx and others are actually relatively simple. It's a std industrial process – nothing lost really?

[Roger HeadParticipant @rogerhead16992]

Ah, I watched Michael's video. Now I'll watch yours, Murray.

Roger

Edit: Yes, that was interesting Murray. I noticed that they made a point of adding a slight lead-in chamfer on the internal operation, it's the sort of thing one would probably do automatically for an external operation, but may not think of for the internal case. At least, I think that I wouldn't think about it. Hmmm, …thinks…

When I referred to 'lost in the archives' I wasn't talking about the process, but about the simple-yet-effective implementations developed by M.E.s. Those that read it at the time Michael originally posted would undoubtedly have made a mental note for future reference, but those of us who came later were blissfully unaware of it until the thread was re-awakened.

 

Edited By Roger Head on 06/05/2016 12:56:40

Edited By Roger Head on 06/05/2016 13:12:26

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