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I asked over on the PM forum how pinion gears were made , & here's the 2 reply's I got

. I expect the oldest ones were simply machined from bar stock. Later, they could also be cold formed, hot formed, sintered powdered metal or investment cast, to name some possibilities.

?you can see a common way to cut bevels. Towards the end you can see how the cutters work. One cutter does each side of the tooth, and the reason you see the cutter head rotating towards the end is, the bevel is a cone. The workpiece is also rotating, this is to create teeth that are fatter at the outside end. It's two cones rotating against each other.

It's also two cutters because the teeth are tapered. A single cutter can't get fat and skinny each stroke as it goes back and forth so you need one for each side, at an angle. You can see the angle.

It's also a pretty old machine, I've never seen a 12 that didn't have hydraulic clamping

MUTE THE MUSIC!!!!!!

if ya don't can't say I didn't warn ya .

pretty darn cool machine

animal

On 5/8/24 1:38 PM, John Lindo wrote:

Charlie. thanks.

I may have to go the route of fly cutting, making an involute bit. I am sure the problem is surrounded by the?

major dia of the Mod 2 12-?13 T?which is 58 mm dia.

I had no issues with the spiral/bevel gear as I managed to be able to use the full diameter of the gear cutter.

Again the indexer and the drive stepper motor cranked at 20 degrees, the area for the teeth was also turned?at 20 degrees.

It's very difficult to measure the end of cut radius of the existing toolhouse chuck pinions, I get something like

a 12 mm rad, thus maybe making a fly cutting tool that has a total swing of 24 - 25 mm dia.

I dont think a "d" bit would cut it sorry for the PUN as they say LOL, normally these are used for?

reaming into an existing hole, IE no zero side load, also turning a tool with an involute shape would require some?

type of radius toolholder.?

Making a bit should not be a problem, use 10 mm dia drill rod, an 8 mm end mill in a vertical mill and with several X and Y moves would get me pretty close to a Mod 2 involute. I have Ivan Law?s

Cheers

John

On Wed, 8 May 2024 at 20:26, CLevinski via <clevinski=[email protected]> wrote:

Hi, John,

I'm no gear expert like you. I did notice, however, that, in the original pinion, the lowest space at the root of the space between teeth seems to be a constant width. If one mentally restores the angle cut on the O.D. of the blank, It almost looks like some specialized vertical end mill was used to cut the shape. Might it be possible to fabricate an equivalent, perhaps some kind of D-bit? I know that the challenge would be the side loads without a guiding pin on the end.

Just a thought...?
--
Regards,

Charlie
New Jersey, USA

NOTE: No trees were injured in the sending of this message,

but a large number of electrons were terribly inconvenienced.

--
John