Source for wormgear system-building rotary stage

[jakovn]

Where can I obtain worm gear system, which device? I know there is wormgear in windshield wiper motor, window lifter... where else? I just want to get to most affordable one but if there is a very affordable manufacturer you can recommend, do it please.
I want to build small rotary stage, and they are very expensive, I'd like to come with less than $400

[Fixittt]

You can get a sherline rotary table for less then $400 already built and cnc ready

[TOTALLYRC]

Originally Posted by Fixittt You can get a sherline rotary table for less then $400 already built and cnc ready

Dear Fixittt.
I have told you before, that is way to easy!!!!!!!!!!!

jakovan, I have the sherline and it is real nice. I hope to use it soon.

Mike

[Geof]

Originally Posted by Fixittt You can get a sherline rotary table for less then $400 already built and cnc ready

In Bosnia??????

[TOTALLYRC]

Originally Posted by Geof In Bosnia??????

You mean there are different parts of the world where you can't get cnc components when you want and for a price you would like to pay?
I am totally shocked!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mike.

P.S. I missed the Bosnia too.

[jakovn]

Thank you for the recommendation.

I need to order it online anyway since here I can't buy even bolts.

[Fixittt]

Originally Posted by TOTALLYRC Dear Fixittt. I have told you before, that is way to easy!!!!!!!!!!! jakovan, I have the sherline and it is real nice. I hope to use it soon. Mike

My momma said work smarter not harder!!!!!!!

I totally missed the bosnia part as well, but no matter what he orders from just about anywhere, the shipping is going to be high, so I think it kind of equals out at least in my mind it does. Ohh and yes its quite crowded in my mind

[BillTodd]

I saw one somewhere made using a simple (threading) tap (I'll try to find the link for you)

He used disc of brass of the correct diameter to give a integer number of gooves, then fixed the disc on a lathe horzontally, so it was free to revolve around its centre. He cut the gooves by pressing the edge of the disc against a long tap held between centres.


[Edit]

Not the one I was thinking of but...

http://mini-lathe.org.uk/worm.shtml

[Geof]

Originally Posted by BillTodd ...He used disc of brass of the correct diameter to give a integer number of gooves, then fixed the disc on a lathe horzontally, so it was free to revolve around its centre. He cut the gooves by pressing the edge of the disc against a long tap held between centres....

This can work like a charm.

I took it a few steps further as I show in post #6 in this thread:

Single point gear cutting

Doing it with the disc spinning freely you have to get the OD of the disc correct so that the initial cut is 'in phase' after a full revolution, but it is possible to do this with a bit of experimentation. With my setup the disc and tap were geared together so the OD did not need to be as precise.

Using an acme tap actually generates a correct gear tooth form that meshes perfectly with an acme screw with very little backlash. A limitation is that you cannot put very much torque through it because the drive is only taken on one tooth at a time.

[Andre' B]

Some google books on worms and worm gears.
http://books.google.com/books?id=7scJAAAAIAAJ

This one looks like it could be developed into a light duty zero backlash high speed ballbearing rotary axis.
http://books.google.com/books?id=fPoOAAAAYAAJ&pg=PA65

[jakovn]

I found out that shipping to Bosnia would be very expensive so I decided to make it myself... except for worm wheel and the spiral shaft... so I am returning to my first question, refined:

Which car part has worm system in it?

Can I find it in car gearbox, and which car model (If you have seen particular one)?

[Geof]

Not in a car gearbox to my knowledge.

I think you should see if you can find an old burnt out gearmotor at a junk yard; these have wormgear reduction many times.

It is possible to make a worm drive using an ordinary spur gear which has the teeth straight across not at the helix angle of the worm. What you do is mount the worm at an angle so it meshes evenly with the gear.

This arrangement cannot transmit as much torque because the curved worm only make a small area of contact on the straight gear but if it is just a moving stage maybe you do not need much torque.