Cutting a small worm-wheel

[KB]

 I'd read about using this technique but had never tried it.

I turned some blanks with a 3/16 ID. 5/8 OD, 1/4 thick.

Pressed a 3/16 dowel into a scrap of aluminum. Put a 1/4 dowel in the chuck and raised the jig to touch.



<a href="https://www.youtube.com/watch?v=ie7dNOLgno0" target="_blank">http://www.youtube.com/watch?v=ie7dNOLgno0</a>





Not pretty or proper but should do.

[rleete]

Well knock me over with a feather, that is just too cool.  Never knew you could do that.

[Bogstandard]

Very well shown Kevin. Showing just how easy some things can be done.

It might not be perfect dimensionally and profile wise, but I am sure that it would do for 99% of the things we get up to in our shops. Just match it up to the same sized bolt as the tap, et voila!, a perfectly usable worm and wheel.

Just the sort of quick and easy tips we need.


John

[gerritv]

Certainly makes you realize how much can be done on a lathe!

Does it have to be a spiral tap to work or will a straight flute starter tap also work?

Gerrit

[KB]

Cheers!

I cut it dry for the camera but a flood of coolant would have flushed the chips and produced a smoother cut.

This is the only time I have tried it, and a spiral tap presented itself. I think a straight flute tap would be fine as long as the second tooth makes contact before the first finishes cutting.
I.E. probably wouldn't use a two flute, or a wheel diameter too small.

Now I can turn the mating thread, mic across the two and add a couple thou to find my centre distance.

KB

[wlb]

I cut one with a straight flute tap using the plug/final tap which is still in use. This was in aluminum I also tried cutting one in MDF but did not come out to good as you could not get the the tap to turn the wheel round without a little help. I made mine for the down feed on my miller.

[steamer]

Nice Job Kevin!

Dave

[KB]

I made another one for a job that I have to do.

The blank was 2.984" OD, .500" thick.


<a href="https://www.youtube.com/watch?v=XIzlg_uObwQ" target="_blank">http://www.youtube.com/watch?v=XIzlg_uObwQ</a>

[peatoluser]

A superb job! I shall definitely file this technique away for future use.

thanks for showing it

peter

[ths]

That's great, Kevin. What was the thing you used it in? It looked really good!

Cheers, Hugh.

[KB]

Thanks all!

Hugh, that's a 5C collet indexer I needed to motorize for a grinding job. I'll post a picture, when I finish the rig, after some holidays.

Cheers.

[Maryak]

Great  Result Kevin 

Best Regards
Bob

[KB]

Cheers Bob!


Here is the rig I built. I had to grind a 5 degree taper on the face of some hardened pins. The diameter of the flat on the tip of the pin had to be +/- 0.003".
So at 5 degrees, It had to be +/- 0.0001 on the depth. So I turned to the surface grinder.
I borrowed a microscope that has two vertical lines, controlled by a micrometer thimble to optically measure the diameter.













This a a piece of drill rod to test it out. The final pin will be ground on the face.




<a href="https://www.youtube.com/watch?v=2mNz9EiRtiI" target="_blank">http://www.youtube.com/watch?v=2mNz9EiRtiI</a>


It is a one off job, so that is why I didn't mind trying out the mickey mouse gears. You wouldn't want to use this method to transmit any load.

Cheers,

Kevin

[Brian Rupnow]

Was there any "mystery math" to come up with the diameter of the blank? How did you determine the depth of cut? Did you cut partial depth on the first cut and then advance the gear closer to the tap or did you cut full depth in one pass? This is very neat, and I will try it myself. Thank you for posting this.---Brian

[KB]

Hey Brian, good to see you here.

The circumference needs to be a multiple of the pitch of the tap.

My stock was 3", so (3 x Pi) / .0625 (pitch of tap)= 150.796... 

We round it down to 150.

150 x .0625 = 9.375 (our circumference) / Pi = 2.98416 (our blank diameter)

This time I slowly plunged the blank straight into the side of the tap. I went a little past half of the nominal diameter of the worm threaded rod. a tap with a centre hole in the end would have been a much more rigid set-up.

Cheers,

KB