# Lathe broach...old concept......my style



## Suzuki4evr (Apr 11, 2018)

I am posting this in this room,but it is not a project of the day but rather days.

When it comes to keyway  broaching in the lathe I usually had a bit of a sigh on on my face, because I am not a big fan of moving the carriage back and forth all the time and a specially when doing keyways in taper bores. Those I am not a fan of at all. I don't think the compound rest screw was designed to take so much force for broaching. Sooooo lets make a broaching tool. I've been wanting to for a while now and a job came in wich required blind 8mm keyways. 
I made a lathe drill holder a short while ago so I thought I am going to modify it so I can use it for this purpose aswell.
I just had to mill out a section for a the hinge mechanism and I made two bushes out of teflon,wich is fine for this in my opinion.


I guess I could have made this much simpler,but I wanted it nice......that's just me.
This is the hinge parts. Forgot to take pics of the manufacturing process.


 I must say my new Vertex BS-0 dividing head came in pretty handy on this project,I just got it in time.




I made a nice strong broaching arm with a fine knurled handle section on it.






 The broach rod has a removable part in front for different size bores and key sizes.


I realised how important the broach tool form actually is. This shape worked best for me. 


The final product and it works pretty well.




Thanks for watching 

Michael


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## benmychree (Apr 11, 2018)

I'd think that the cutter pictured has too much front clearance, and might tend to hog in.


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## brino (Apr 11, 2018)

Suzuki4evr said:


> Thanks for watching



Thanks for sharing!
It looks great.
-brino


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## MAKEITOUTOFWOOD (Apr 11, 2018)

Very cool. Thanks for posting.


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## woodchucker (Apr 11, 2018)

That's a lot of overhang off your toolpost. Does it flex much?


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## rgray (Apr 11, 2018)

I think I have seen a version like that with a vertical handle.
That horizontal handle looks much more user friendly.


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## Suzuki4evr (Apr 12, 2018)

benmychree said:


> I'd think that the cutter pictured has too much front clearance, and might tend to hog in.


 Are saying that the toolbit will dig into the workpiece. I did not see that happening,the tool was rather tending to push away from the material a little bit because of the bar diameter. I played around with the toolform and kind of copied a broach I have and this form worked well.


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## Suzuki4evr (Apr 12, 2018)

S


brino said:


> Thanks for sharing!
> It looks great.
> -brino


Sorry Brino,"SHARING". I don't know what is going on with me these days, it seems I am on a roll with bad spelling and wrong words lately. Must be getting old it seems.


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## Suzuki4evr (Apr 12, 2018)

No


woodchucker said:


> That's a lot of overhang off your toolpost. Does it flex much?


Hallo Woodchucker.No, it is a real sturdy setup. I think the pic doesn't do it justice.When I made the holder originally as a lathe drill holder I actually did want to make to fit directly onto the QCTP,but a combination of lack of time and a bit of urgency forced me to make it as quick as possible.


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## Suzuki4evr (Apr 12, 2018)

rgray said:


> I think I have seen a version like that with a vertical handle.
> That horizontal handle looks much more user friendly.


It works quite smooth, but in afterthought, I wish I made the handle a few inches longer just to get a bit MORE leverage, but I made the measurements up as I went along. Last knight I had an  idea to mechanise it by removing the hinge section and handle completely and installing a low RPM high torqe motor of somekind with a centrifugal bush and rod on it and then my bad sholder won't have to do all the hard work anymore. If someone has an idea of what kind of motor I can use it would be greate. I thought of using a wiper motor seeing that you can use it to make mill bed autofeed mechanisms,but i am not sure if the torque would be sufficient. Maybe someone can advise me on this.


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## brino (Apr 12, 2018)

Suzuki4evr said:


> If someone has an idea of what kind of motor I can use it would be great



an automotive door window drive motor would probably have more torque.
-brino


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