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

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Suzuki4evr

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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.
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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.
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I must say my new Vertex BS-0 dividing head came in pretty handy on this project,I just got it in time.
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I made a nice strong broaching arm with a fine knurled handle section on it.
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The broach rod has a removable part in front for different size bores and key sizes.
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I realised how important the broach tool form actually is. This shape worked best for me.
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The final product and it works pretty well.
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Thanks for watching

Michael
 

benmychree

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

rgray

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

Suzuki4evr

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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.
 

Suzuki4evr

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S
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.
 

Suzuki4evr

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No
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.
 

Suzuki4evr

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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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