Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: poppabear on November 25, 2011, 09:33:24 AM
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Greetings,
This is a slightly off topic question, but I am hitting a wall on a machine design.
Does anyone KNOW of a Gear manufacturer that sells, PRECISION Gears that are AFFORDABLE?!!!!
Little to none, or adjustable backlash (by maybe moving center distances).
I need a supplier (preferably in the US, where I can speak to someone who speaks understandable English).
Accountable quality control would be a must. Thus the US (or Canada), request above.
I am building a very custom "A" axis, plus an indexer so I need:
- Worm/Wheel gears (with large diameter ID in the Wheel.
- Right Angle Bevel Gears.(Helix or striaght is ok as long as low to no backlash
I was going to cut my own, but, I got a quote from a company for a HOB to do the Worm/Wheel above an it was INSANELY
expensive, they wanted almost $900.00 dollars plus 13-14 weeks lead time......... They must be on Crack.
Scott
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We usually get that sort of thing from Stock Drive Products or Quality Transmission, although finding someone who knows anything about the product is a challenge. You pretty much have to know what you need and order it on-line.
http://www.sdp-si.com/
http://www.qtcgears.com/
We're slowing coming to the realization that if we can't make it in-house, it can't be done. Trying to find reasonable price, acceptable quality and engineering/tech support all at the same time is just about impossible. Machine shops around here are completely insane on price. The last job we needed done was quoted $3000, which was no more than 5 or 6 hours on a manual mill. We bought a used Bridgeport for $1500 and did it in house.
We now need to run some production on a mill, so we're looking for a CNC. I found a SuperMax with a Anilam controller. The controller is supposed to be dead, so thinking about putting a Mach3 controller on it. It's not even worth the ride downtown to get a quote on having these jobs done locally.
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HIYA SCott Face with that I usually find a surplus gear box and use the gears out of it to build what I want.
Also don't know the size you are looking for but gear sets from small rear differentials (golf karts,etc) are a source as well. Most are precision ground and hardened.
Also look into the outboard motors lower units. A lot of them went to precision gears and are in the small range.
Just a thought, (;-) TP
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Scott have you thought about belt driving the 4th?
Just a thought, (;-) TP
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need a worm gear to hold the rotary, belts cannot hold against the moment of cutting force toward the outside of the rotary table.
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What ratio? What size center hole?
(;-) TP
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Little to none, or adjustable backlash (by maybe moving center distances).
Almost by definition, zero backlash means you can barely turn the gears.
Big questions:
What diameters are you looking for?
Is this for production use or just for a short job?
Can one gear be brass (the big one)?
I have heard of people making their own worm&wheel sets using a large tap. Seen it done once. Yep, can be done that way.
Also, if you google 'hob cutter' you will find a number of web sites which show how to do it fairly easily.
Note: for prodduction use you probably want to go for the full involute gear profile. But for a 'quick fix' a much simpler profile is quite usable. Adjustable backlash is required...
Cheers
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Have you considered a harmonic drive? If you really want low backlash and a pro-setup as well as reasonable speed it is hard to beat a good harmonic drive. They are not exactly cheap but sometimes you can find a good deal on the bay...peace
Pete
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Roger,
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. There are many other considerations as well to this.
Dan
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Have you looked at Simpson's posts on his 4th axis?
If too small then what size are you talking about?
One can always modify a lathe or mill head.......
RICH
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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
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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
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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
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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.
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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
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do you have a way to grind the hob if you make one.
bill
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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
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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
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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