Flexible small drive shaft?

I haven't found anything that looks usable at McMaster Carr, unless
I'm overlooking something. Can a flexible drive shaft be made from a
simple spring, like inside a rotary tool flex shaft? Whatever stuff
used for flexible shaft screwdrivers?
The shaft will be driven by an 18 to 36 V DC motor (up to maybe 700
watts). Not sure the RPM, typical DC motor. Bent 90° in about 3".
Thank-you.
Reply to
John Doe
Loading thread data ...
An appropriate size steel rope inside a guide tube should work. The more strands the more flexible it would be. You just need to fashion attachment fittings welded, clamped, swaged or bolted at each end.
| | I haven't found anything that looks usable at McMaster Carr, unless | I'm overlooking something. Can a flexible drive shaft be made from a | simple spring, like inside a rotary tool flex shaft? Whatever stuff | used for flexible shaft screwdrivers? | | The shaft will be driven by an 18 to 36 V DC motor (up to maybe 700 | watts). Not sure the RPM, typical DC motor. Bent 90° in about 3". | | Thank-you. | | | | | |
Reply to
E Kinney
======= click on
formatting link
?wo=2004073378
formatting link

Unka' George [George McDuffee] ============ Merchants have no country. The mere spot they stand on does not constitute so strong an attachment as that from which they draw their gains.
Thomas Jefferson (1743-1826), U.S. president. Letter, 17 March 1814.
Reply to
F. George McDuffee
700 Watts is almost one horsepower
-- Boris
Reply to
Boris Mohar
According to John Doe :
The core of a flexible shaft is alternating layers of clockwise and counter clockwise windings, so a simple spring would either expand in one direction (and bind) or contract in the other direction, and rattle around inside the buide.
If you want flexible shafts to build from, try picking up a speedometer cable -- unless you need more torque than that can carry.
That's a pretty sharp bend for a flex shaft to handle the likely torque from that motor. Are you sure that you won't do better with a set of bevel gears?
Enjoy, DoN.
Reply to
DoN. Nichols
"Boris Mohar" wrote: 700 Watts is almost one horsepower ^^^^^^^^^^^^^ Correct. If you are trying to transmit that much power at low RPM. the torque will be way too high for a speed cable. If you're trying to run it really fast, then the torque won't be the problem, but turning 90 degrees in 3" will be, because the cable will be rubbing on the outside of the housing, and it will get REALLY HOT.
Look at a Weed Whacker type thing to get an idea what you need. Or a Dremel flex shaft drive.
Reply to
Leo Lichtman
Speedometer cable if it's not too small ............. ?
Steve
Reply to
SteveB
newsdbm02.news.prodigy.net!newsdst02.news.prodigy.net!prodigy.com!newscon02.news.prodigy.net!prodigy.net!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
Reply to
John Doe
"Boris Mohar" wrote
Conclusion: that would be too small.
Steve
Reply to
SteveB
--For that kind of power maybe what you need is a miniature one of these:
formatting link
--Can't remember what they're called but they work pretty neat. Photo #3 shows the most detail.
Reply to
steamer
Good pics.
If I can't get what I want, it's just as good to know what I'm up against.
Thanks.
Reply to
John Doe
Try doing a search on model power boats. Some of them use flex shafts, and the larger ones might be usable.
You could also search on flexible shafts. There is at least one US company that makes them (S.S. White???), and their website will help you select what you need.
Howsomeever, it sounds like you want to transmit a LOT of torque over a tight radius. Consider bevel gears insteads.
Reply to
freemab222
If you want 90 deg. use a bevel gear assembly. Boston Gear has this sort of thing and you can sometimes luck in on ebay.
For somewhat less bend, universal joints work nicely. They make them for ratchet drivers and you can often get them at the discount tool stores.
These places also have the kind of flex shafts that you originally asked about. Same original application as the universal joints.
DOC
Buy my junk!
formatting link
Reply to
doc
John Doe wrote in news:Z63Ai.13272$4w7.12330 @newssvr22.news.prodigy.net:
How LONG will the shaft need to be?
If ~6" would work, how about using one of the flex-drive extensions for a power screwdriver?
Reply to
RAM³
formatting link
formatting link
formatting link
formatting link

Dave
Reply to
spamTHISbrp

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.