# Broaching questions



## KMSK1 (Apr 10, 2013)

I want to broach a 1/8th hole square  1/2inch deep ???? 
Can you stop the broaching clean out chips and then start again ??? 
Thank you for any help ,,Robert


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## portlandron (Apr 10, 2013)

Not an expert on broaching but have done it
. 
First you do not want to pull a broach backwards, just like not turning a ream backwards, you will damage the cutting edge of the teeth.

There is no need to stop and remove chips. When broaching you do not remove that much material in a single pass and there is enough space behind each tooth of the broach to hold the chips.

The main danger in when using a broach is pushing the broach at an angle and breaking it.

Here is a video that shows broaching being done    [ame]http://www.youtube.com/watch?v=ZRbOux9NfeU[/ame]


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## easymike29 (Apr 10, 2013)

Are you asking if you can broach a blind slot, not all the way through?

Gene


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## Rivergypsy (Apr 10, 2013)

If you do broach blind, then id seriously recommend a groove at the back of the bore to give the swarf somewhere to go before it breaks the tool ;I)


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## Lakc (Apr 10, 2013)

Look at your socket's from your socket wrench collection, find one that has been formed by peeling the surface inward. Thats commonly called a rota-broach operation, which is what you want.


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## KMSK1 (Apr 11, 2013)

Wow iam a newbe for sure ,,I didnt ask the questions correctly ,,,Thank you for all your replys ,,Let me try this again ...
I just bought a Janco Rotary broach tool holder for my Griz 9x19 lathe 
I want to broach a 1/8th inch hole 1/2 inch deep ,I ordered a broach that has been ground to that distance,, 
First what is the best place to hold the broach to the cross freed /tool post or the tail stock????
Can I while broaching a hole that size that deep stop and clean out the chips and then start again ,, Thank you for any help..Robert


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## Lakc (Apr 11, 2013)

KMSK1 said:


> First what is the best place to hold the broach to the cross freed /tool post or the tail stock????


Never had the pleasure of using one, so take this with a grain of salt, but I believe you want the rigidity of the tailstock for this. 


> Can I while broaching a hole that size that deep stop and clean out the chips and then start again ,, Thank you for any help..Robert


Its usually one continuous chip per side, but with the right tool you may be able to break it off and restart.


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## abby (Apr 11, 2013)

No mention of material to be broached ! brass is very easy and holes up to 1/4" diameter can be cut using the tailstock of a Myford sized lathe. Cut in one pass , allow a space under the broach for the swarf.
Steel is obviously harder than brass but 1/8" should be no problem , you can make the broach from silver steel (drill rod) hardened and tempered.


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## MachineTom (Apr 11, 2013)

A Rotary broach cutter tool end is on center. The holder is set at a angle of 5° or so, so the cutter shank is angled away from center, I've only seen the type that mount to a tailstock/turret. While it could be mounted to the crosslide, it all depends on what the holder is set up for, and how ingenious you are.


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## KMSK1 (Apr 11, 2013)

So if I get rid of the blind hole ,I should be able to broach all the way threw with out to many problems ,,How about 1/8th broach custom ground to half inch long? see any problems there ,,Thank you for your help,,,
metal ,,soft steel .alu


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## lohring (Apr 12, 2013)

Lots of information on rotary broaching in this thread.  A video of the process is here.  You can broach both blind and through holes.  It's definitely the way to go for small holes.  There are some moderately priced tools and holders on ebay.

Lohring Miller


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## KMSK1 (Apr 13, 2013)

Thank you I read it ,,It doesnt answer I one main question ??????
Can you stop broaching 1/2the way in clean out the chips ,,then re-start the broaching to the end ??Thank you Robert


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## lohring (Apr 14, 2013)

Not without manually realigning the broach.  Making the hole deeper than the broached shape to contain the chips is recommended.

Lohring Miller


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## KMSK1 (Apr 14, 2013)

Thank you ,,So for me to understand in my terms is this ,,I want to broach a hole 1/2  inch deep ,So I drill the hole 5/8 deep ,broach 1/2 deep should be good .. Or bored a hole in the side at the bottom of the hole for the chips to come out of ,,Thank you Robert


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## lohring (Apr 15, 2013)

Here are the answers from professionals.

Lohring Miller


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## KMSK1 (Apr 15, 2013)

Thank you for your time and help,,,Robert


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