Shaft Connectors
Bill Chennault
Posts: 1,198
All--
I need to connect two shafts, both about the same size (0.118" or so). One is square and the other is a "D." Can you point me towards a source for shaft connectors? (Just something in general; if I have a link I can research from there . . . as I will do right now.)
Merry Christmas!
--Bill
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You are what you write.
I need to connect two shafts, both about the same size (0.118" or so). One is square and the other is a "D." Can you point me towards a source for shaft connectors? (Just something in general; if I have a link I can research from there . . . as I will do right now.)
Merry Christmas!
--Bill
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You are what you write.
Comments
Maybe I will just make this little rigid coupling. Say, 1/4" or 3/8" rod, drill an undersized·hole through the center, shape one half (or less) of·the length of the hole square with a needle file to fit the square shaft, leave the other half round, but ream it to a precise fit, drill and tap both ends for set screws?
In reality, I could probably get away with leaving it all round and maybe putting two set screws in the end that is supposed to fit the square shaft. That would reduce my "manufacturing" significantly and give me a good enough coupling for my experimental use.
--Bill
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You are what you write.
To mate shafts with different style ends, I have used thick-walled heat-shrink tubing. As long as there is not a lot of torque involved, it works pretty well.
You'll have to search around for a distributor, but this is an example of what I'm talking about:
www.rinomechanical.com/shftcoup.htm
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Roger Pierson
Senior Electronics Technicain
DTI Assoicates
KatyBri: Thanks! But I need to move quite a bit of torque and wonder if shrink tubing would work? (What a great idea, though!)
Roger: Gee. Rino has exactly what I need! The only problem is that their minimum order is $250.00. Still, if I figure out the precise part, I will need about 16 of them. (I e-mailed them for pricing and they responded within seconds.) They referred me to mcmaster. I THINK I have looked at their site, but not for couplings.
--Bill
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You are what you write.
It appears that McMaster has an even greater selection and their minimum order is ten bucks! (I have bought stuff from them before.)
--Bill
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You are what you write.
Another common sourse I use for misc. hardware is Fastenal:
www.fastenal.com/web/home.ex
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Roger Pierson
Senior Electronics Technicain
DTI Assoicates
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Chris Savage
Parallax Tech Support
0.118" isn't much of a shaft. The Japanese mechanical toy company TAMIYA, uses small square shafts and has plastic fittings to adapt wheel hubs. If that is the same origin as yours, you might do better to stay with all square shaft as the torque transfer is quite good for a friction fit.
For really small shafts, collets provide a much better grip than a set screw. Some of these are available from R/C Airplane and Boat people. Set screw is the for the next increment up [noparse][[/noparse]usually 1/4' shafts]. Larger shafts use keyways to transfer substantial torque.
Going to a larger shaft size might actually make it easier to find fittings. If you use aluminum tubing for your shaft, the weight is somewhat reduced [noparse][[/noparse]50% of iron], while gaining a size that is workable.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
Parallax often orders from Rino Mechanical (parts for Toddlers, Penguins). I've never known that we've had to experience with their $250 minimum order. If there's a part (or many) you need from them, tell me what it is and I'll get it for you.
Ken Gracey
Parallax, Inc.
The square shaft is actually 0.10" on a side. It is a right angle attachment for a rotoray Dremel tool and may be good for what I need if I can connect it to the 0.118" shaft of my chosen Banebot gearmotor.
I have ordered a (very inexpensive) slotted disc coupler from McMaster for testing. However, it is 0.125" in diameter. Maybe a little too big.
I've also thought of making my own out of aluminum or mild steel rod stock. But, anything I made would not have a misalignment capability.
If I can mate the shafts, the Dremel right angle attachment ($29.00 at Lowes) will be a good solution for a lot of motors. I have collets laying around and thought about them last night after I went to bed. Basically, I need to make the gearmotor look like the end of a Dremel rotary tool. I don't think it will be too hard. In fact, IF I can do that, then there is enough slop in the Dremel supplied square coupling to take care of misalignment.
--Bill
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You are what you write.
Thank you! I will remember your offer.
--Bill
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You are what you write.
But that square shaft is a troublesome item.
Much depends on how many RPMs you are spinning at. A Dremel tool usually spins at thousands. This requires a very good fit. But it you are running at 300 RPM or less, you might find that the fit isn't too critical.
I am assume the square is a shaft, not a female fitting. Can you cannibalize the counterpart {the female fitting} from something and adapt it?
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
Post Edited (originator) : 12/20/2006 8:36:52 PM GMT
as the square edges should make their own slots in the coupler...
Bob
Thanks for the good advice!
Kramer: For the first effort, I will be using a 26 rpm gearmotor at 535 oz-in, free-running. So, pretty slow.
originator: I'll definitely check out that link you gave me!
Bob: Thanks for the hint on sizing. Great idea.
I have a "slotted disc coupling" coming from McMaster-Carr. I believe it is about 0.007" too big. But, it will give me some ideas. I believe I have everything I need to make a rigid coupling. I could probably put enough slop in it to take care of any misalignment.
--Bill
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You are what you write.