PoppaBear needs some help please!!!

[Tony Bullard]

I don't know how big is big for your ID but lets say you used a 4 diametral pitch, 64 tooth, 16" OD off the shelf brass Boston Gear worm (G1105) and bored the center out of it and bolted it to your table. The worm shaft bearings could be adjustable axially to minimize backlash. $500 bucks from Motion Industries.
Tony

[rcaffin]

While making a worm wheel with a tap like some do will transfer the movement, it shouldn't be considered for efficiency critical or, more importantly, for high load transmission applications. The tooth profile is not thick enough to carry high loads and the helix would be probably too small leading to reduced efficiency.

Yes, of course, but what is the worm&wheel for? If it's for a one-off job then the result might be acceptable. If it's a one-off for a short job, maybe efficiency is not a prime consideration? As for load transfer - -  big teeth!

Scott - you might think $900 for a hob is expensive, but that is doubtless for a hob which could make 1,000 units or more. Each of which might sell for $200. Maybe the capital cost is not that high if you want serious production use?

Cheers

[Tony Bullard]

How precision? How about a ring gear from a car engine and press fitting it on to your table. adjustable pinion gear for backlash. Cogged belt reduction for torque absorption?

Tony

[mrprecise44]

Hi Scott:

I have done business with this company for many years, and they do speak English.
You can walk in the door, and talk to the boss. A long established Los Angeles gear company.

www.americanchainandgear.com/

Give them a call.

[poppabear]

My application is for a Rotary Table CNC grade. Looking for a way to cut a 6" (approximately can be plus or minus) wheel. And a way to cut a Worm.
I am putting a 1 KW AC servo on it, so it will need to be strong, but accurate. It is a custom application but for a custom CNC machine.

I would like to be able to cut/make my own, since I am interested in learning the technology of this. I have a Mill and Lathe to cut with.

I don't mind even if I would have to make a single tooth cutter, or buy a Involute cutter, but a Gear Hob would be the best, but they are to high. I have NOT had a lot of luck on finding resources (books, how-to's, etc.), on how to make your own Gear Hob. Obviously, this is a closely guarded secrete, or, I just don't know what terms to put into google.

Harmonic Drive: Yes, I had thought about these, but they are also, far to expensive. Don't do ebay on stuff like that, since you don't know what your getting, nor do you get any kind of warranty on the part. If it goes down, then I am really out of luck.

I have never cut gears of any kind before, so, in essence, I am a total numb-skull in this area. I have looked on the net for Worm/wheels cutting, and have seen the "I used a tap" etc. type, but none for larger/stronger gears nor precision stuff.

Sorry, not trying to be difficult, and I may be having a "Pipe Dream", on doing my own that is affordable to make, and precision as well..

scott

[docltf]

do you have a way to grind the hob if you make one.

bill

[BR549]

HIYA SCOtt, What ratio are you tryin to acheive.  What you are asking is BIG project for a newbie wanting to do an extreme accurate gear without a gear hobber or gear grinder. Can be done BUT(;-) I would not do it on a custom device for a customer as a first project.

Look over at Surplus Center at their selection of worm gear reduction drives I see a couple of through hole 20:1 wormdrives for $89 AND they are rated for about 2hp .

(;-) TP

[RICH]

Scott,
Sent you an email. Tend to agree with TP on looking for something usable since  you will need to have someone heat treat the gears if you can make them.
In the end you may spend a lot of effort, yes you will have fun,...but....you probably won't be satisfied with the homebrewed gears.

RICH

[RICH]

Scott,
Do you have a Machinist Handbook? It has a rather good section on worm gearing. One way of cutting the  worm and warmgear is using an Acme thread cutter.
Depending on size of gear, you may want to try cutting the worm on the lathe using the alternate feed method, still need to do the multiple threading , but using the alternate feed method you can more easily cut the worm. That wasn't in the info i sent you.
RICH