Slotting and Broaching tool for the Lathe

[jjr2001]

I have tried the "no tool method" by just using a cutoff tool in a tool bit holder and that works but it does
put a lot of stress on the carriage gear train. (Manual Feed Gears). There are a lot of examples on the net
using a dedicated tool in the tool post. I tried that method but with my little lathe rigidity was missing.
So I reverted to mounting the new slotting tool with a tool post riser and removing the compound and QCTP.

The block of aluminum is 3" by 4" and about 1.75" thick. The bushings are 3/4" ID and 1" OD.
The hole for the bushings was simply bored straight through. I added a hole (set screw plug) in the top
of the tool body so that I could fill the area surrounding the ram with oil. The bushings were a slip fit and
then I set them with blue loctite so the oil does not leak out.

Ram is 3/4 drill rod with factory finish and it is a nice sliding fit in the 3/4" bushings. The handle is 1018 steel
and is 3/4" wide and 1/4" thick. I used either shoulder screws or allen cap screws for all fasteners. The link is
a chunk of brass that is kept well lubed in use.

First trials with it mounted on the riser showed that it would rotate against the riser when high forces were applied.
I solved that with the little steel clamp that locks the slotting tool block to the riser. Works fine now.

The boring bar type tool holder was going to be the tool bit holder of choice but after trying my "rota-broach" type
tool bit I think they will be fine for some types of work.

There is a test piece in the chuck in a couple of pictures. The nice thing is that this tool will broach out a round hole to
be square by using one of my square broaches. The square broach can be used internally or externally. I was also able
to make the square broached hole larger by rotating the chuck 90 degrees and moving the cross slide in a few thou at a time.
Then by moving the tool up or down with shims the square cut could be enlarged to whatever you wanted. Using the smaller
tool bit and enlarging the square hole with it will keep the forces lower than if going to a large bit.

I need to make more tool bits for smaller sizes and will do that next. It looks like the tool will be very useful
putting keyways in gears and shafts for my model engines.

Cheers, JR

[rossbotics]

Nice setup JR. you did a nice job on your broaching fixture, I been toying with that idea for quiet a while now, you may have just intrigued me !

Doug

[jjr2001]

Thanks Doug, One note about the design. Last night after looking at some builds I found this:

HomeShopTech

I like the design and see that it would remove any tendency for rotational movement of the tool.
Don't think I will make another one since mine does work well. It is easy to take many small cuts to
reduce rotational forces and is much faster than just using the lathe and cutting bit in the tool post.
I can take large cuts and with the little clamp added to the riser it does not rotate.

But who knows, I like to make tools and this "Top Handle" design is a nice variation that solves the rotation problem.

Cheers, JR

[old_toolmaker]

jjr2001,

Great job on the slotter attachment. What do you use to grind the tools to size? Also what relief angle do you find works best?

[Dimitris Polychronis]

That’s a really nice tool, thanks for sharing!

Dimitris

[Altair]

Thanks jjr2001! We've added your Lathe Slotting and Broaching Tool to our Lathe Accessories category,
as well as to your builder page: jjr2001's Homemade Tools. Your receipt:

Lathe Slotting and Broaching Tool by jjr2001

tags: lathe, broach

[jjr2001]

Thanks Dimetris, It was fun to build and will be useful for my model engines.

Dick, I have a shop made all around grinder, "surface or tool bits, endmils, whatever.
Here is the link: http://www.homemadetools.net/forum/s...9982#post71647
I have replaced the motor and added some things to it but that is my basic tool/surface grinder.
Fine Feed Add: http://www.homemadetools.net/forum/u...0461#post72517
Power table feed: http://www.homemadetools.net/forum/u...1384#post74299

Not a show tool but it does get some use in the shop.


Relief angle for the broaching bits is 12 degrees. I just put it in a 5C collet and that makes it easy to get all 4 sides done.
Cheers, JR

[old_toolmaker]

jjr2001,

That is a nice grinder build and it is nice how you salvaged the old X-Y table. I bet it does all you ask of it.

[jjr2001]

So far it has done everything I have asked of it. It is a nice addition to the home shop.
Cheers, JR

[Toolmaker51]

Slotting and Broaching tool for the Lathe

There are a lot of examples on the net using a dedicated tool in the tool post. I tried that method but with my little lathe rigidity was missing.
So I reverted to mounting the new slotting tool with a tool post riser and removing the compound and QCTP.
Cheers, JR

Finely made manual shaper! I thought ill of 'no tool' method as well, on a Okuma! Stout wonderful machine, but the gear rack ratio is to move a carriage quickly, not grunting leverage.
That you built a levered post make sense; the force centers better on the compound instead of hanging farther out in space.
Such tools most people think are only 'small machines - small shop' hobby work. [I won't mention how I dislike word hobby in the context of machine work.]
Ooops.
Your post today, like others, makes me think how to use such techniques on substantial equipment too. For starters, I can't see any serious issue boring index holes into edge of chuck back plate.