On Fri, 26 Jun 2015 17:43:44 -0500, "Terry Coombs"
wrote:

Baron wrote:
prodded the keyboard with:

On Sunday, June 7, 2015 at 3:49:13 PM UTC-4, Terry Coombs wrote:
That's the reduction ratio of the unit I'm building for an X axis
power feed for my mill .
Snag

I looked through the scrap yard today and found two motors with
gear reductions that might work well for that. They were from
battery powered wheel chairs. They work, but are noisy. They have a
lever to disconnect the drive.

So maybe you could check with medical supply / repair places and
find something in their scrap that would work well.

Dan

What on earth is wrong with a normal wiper motor ? I have now built
two and they work great ! Tumbler reverse, centre off and variable
speed.

I have a couple of wiper motors , but the worm gear is messed up in both .
The worm or the worm gear? In either case maybe you would like to try
making your own worm and worm gear. It is actually pretty easy, I know
because I have done it. What you need is a high spiral tap that is the
diameter you want for the worm. Then you can use a piece of a bolt for
the worm or you can single point one. Then for the worm gear, also
known as a worm wheel, you decide how many teeth you want and using
this number and the pitch of the worm and pi you can determine the OD
of the worm gear. Make a disc the proper OD and thickness with a hole
through it. Then make a mount for the lathe to hold the gear blank
horizontal and use the hole for an axle. Put the tap in a collet or
the chuck and make sure it runs true. Adjust the center height of the
disc so that it is on the spindle center. With the tap spinning
present the disc to the tap and start feeding in. The high spiral type
of flute on the tap will make sure that the tap is always engaged with
the work and so will pull the worm gear around as it cuts. So the tap
acts as a hob. When I made my worm and worm gear sets I first used
some all-thread to see if it would work. It did so I made worms from
O-1 and heat treated them. I made the worm gears out of bronze.. They
worked quite well.
Eric