The Home Machinist!

Hello Folks,

Just looking for a bit of input on the best way to cut the radiused groove into the bronze sheave below as shown below.
Would it be best to just grind a raduised bit and plunge the cut? Can someone give me an idea of the proper grind & relief on the bit for cutting 660 bronze.

Secondly - would it be feasible to create the bit out of drill rod ?


As always - thanks ahead for steering me in the proper direction!

click here

thanks again

Ironic, I was just watching some YT videos of radius/ball cutter tools for the lathe.

This one is probably the easiest to fabricate, and other related video will show similar tools:

_________________
Standards are so important that everyone must have their own...
Logan 10x24 Lathe, RF-30 Mill, 20 Ton Press
Disclaimer: I'm just a guy with a few machines...

If the .540 dimension is not critical, how about mounting the stock on a rotary table (vertical orientation) and using a 1 inch end mill? Approach from the side and infeed until you reach the desired depth. If a flat spot at the bottom can be tolerated and you need the .540 then once you reach depth then cross feed .020 one way, make a pass and them .020 the other side of center and make a second pass.

Rick

If you don't have a radius turning tool for your lathe, go to Marv Klotz' website
http://www.myvirtualnetwork.com/mklotz/
and download UGROOVE.EXE. It will output X,Z coordinates to cut the groove using a smaller radius tool bit.

The program was developed to do exactly what you are doing!

It would take a real stout lathe to plunge that with a single form tool.

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Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

If you wish to accomplish the cut by lathe, you likely could achieve acceptable results by grinding a smaller radius tool, so that contact is reduced. As Glenn alluded, a tool that large would be difficult to use unless you have a very robust machine, which is generally not the case for the home shop.

Make a radius gauge with a divider. You can scratch cut one of the desired radius, using brass shim stock. That's essential for achieving your goal. Use the male portion to gauge the groove as you cut with the smaller radius tool, which would be best ground on a piece of ½" HSS stock, for rigidity. Grind a full ¼" radius, them manipulate the tool side to side as you deepen the cut. Remember to grind adequate relief on each side, so the tool can cut. This will take a little time, but will eliminate the need for a radius cutter if you don't have one, and hope to accomplish the mission without adding a new project in order to do so.

You may find you will need a half round file to blend the cuts slightly. Spin polish for finish. With care, you can work within a few thou---certainly close enough for a die for bending.

Harold

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Wise people talk because they have something to say. Fools talk because they have to say something.

I'm just curious, why use bronze?

Actually I was wondering the same thing?

When I made them we used 4140 HT for the smaller ones and EDT 150 for the larger ones. I used a radius turner for them. The small ones we would have a tool ground by a local tool & cutter grinder service. The ones we made were used on a Pines bender.


Richard W.

Hi Folks,

Apologies for the delay in replying.

I do not know why bronze is specified for the project , It is simply what the customer specified, and is going to provide the slugs for the job. I will probably use the "ugroove.exe"/smaller bit as suggested above.

Thanks again everyone for "schooling" me

-todd

Good enough for me! Thanks todd, sorry I couldn't have been any help.
Good luck and let us know how you make out.
Steve