3-D Printing and Spencer Tape Gears

[madhatte]

Gettin' tired of crappy pot metal gears in Spencer tapes. Looking into having replacement gears printed in nylon or HDPE. Probably be about $25 a rebuild. Should last about twice as long as stock or better. Looking to gauge interest here. I won't be selling them, if I get them made. I'll let somebody else handle that. I'll just do the design work and send the files off to the printer. Might mess with gear ratios some, too. Usually I eat gears faster than I do springs, might as well take advantage of the fact.

 

[madhatte]

Should look something like this, material-wise.

 

[brokenbudget]

can you print delrin?

 

[madhatte]

A quick Google search seems to say "not yet", but probably soon.

 

[brokenbudget]

A quick Google search seems to say "not yet", but probably soon.

i know they use it in the rc industry. very strong stuff. they usualy mold or machine it. the best spur gears you can get for any nitro or electric 1/8th scale are delrin. they run against steel clutch bells at ALOT of rpm.

 

[DSS]

I got heavy duty spiders for a very large love joy coupler at work, and it seems to me that's what they called the stuff, delrin. No problems since, its coupled to a 60 hp motor.

 

[brokenbudget]

they can produce it from slightly rubbery all the way to feeling like glass. on the 1/8th scale monster trucks i've had over the years, you get to respect those spur gears. the little engines turn upward of 30000rpm and they use a hardened steel straight tooth cut clutchbell. in very dirty environments. usualy you have to change out the clutchbell before the spur.

 

[madhatte]

This bears further investigation.

 

[brokenbudget]

This bears further investigation.

back when i was on alot of 'nitro rc' forums, people were buying billets and blocks and machining their own bits. maybe that's something to look into.

 

[madhatte]

No time -- wanna print 'em in bulk.

 

[brokenbudget]

No time -- wanna print 'em in bulk.

you're no fun:tongue2:

nylon would be my second choice. it should hold up pretty well.

 

[madhatte]

Well, thing is I'm not really interested in re-inventing the wheel. It's just that the manufacturer went from stamped steel gears to powdered aluminum a couple of years ago and they aren't holding up, and from a couple of conversations with the engineer I tracked down, it doesn't seem like they're interested in changing anything. Spencer tapes are standard equipment in forestry and logging, and a busted gear can stop a day's work cold. I want a fast and cheap replacement for these parts so that I can get a lifetime similar to the old steel gears. Got a suspicion that I'm not the only person who could benefit from such a thing; a limited production run based on an open-source file would mean that I get what I need and anybody else can do the same later. All I want to do is draft the file and get what I need and pass the rest on to the World At Large.

 

[cowtipper]

Well, thing is I'm not really interested in re-inventing the wheel. It's just that the manufacturer went from stamped steel gears to powdered aluminum a couple of years ago and they aren't holding up, and from a couple of conversations with the engineer I tracked down, it doesn't seem like they're interested in changing anything. Spencer tapes are standard equipment in forestry and logging, and a busted gear can stop a day's work cold. I want a fast and cheap replacement for these parts so that I can get a lifetime similar to the old steel gears. Got a suspicion that I'm not the only person who could benefit from such a thing; a limited production run based on an open-source file would mean that I get what I need and anybody else can do the same later. All I want to do is draft the file and get what I need and pass the rest on to the World At Large.

NOT trying to be wet blanket, just something to think about... A lot of people are missing the fact what they are “printing” are patented, and are covered under patented law. Most companies look at a small production run as a hobby. But when you start “printing” them and the selling them then they become a product, and that’s where the problems start. Not saying that’s what going on here, but just something to think about in a LOT larger picture.

 

[northmanlogging]

legalities aside. Depending on the size of gear you can get extruded gear stock, in brass, aluminium, steel, stainless steel, plastics of various types. Most of the stuff I've worked with in the past was under and inch diameter, and around 60" long.

All you would need is the correct pitch, a thickness and hole/arbor size, any jerk with a bench lathe could pound em out.

Just so ya know this is how most watch mechanisms are made, they turn the gears down form longer stock...

From what I remember about the 3d printing it will make a serviceable prototype, but not real good for production, kinda slow and energy expensive. Haven't heard much about them in a few years though.

I didn't realize spencer tapes had gears in em by the way...

 

[madhatte]

NOT trying to be wet blanket, just something to think about... A lot of people are missing the fact what they are “printing” are patented, and are covered under patented law. Most companies look at a small production run as a hobby. But when you start “printing” them and the selling them then they become a product, and that’s where the problems start.

Understood. Not terribly concerned about it; like I said, I'll just make the plans available, and have what I need built. Nobody will be producing and selling these things in any numbers. A handful here, a handful there; it's a niche of a niche market. Pretty sure the gun guys will take the heat for the copyright/patent issues regarding 3-D printing.

 

[LegDeLimber]

I look in over at hackaday and the issues with smoothing out the layer lines from printing is an ongoing topic.
and you've already got "patent trolls" jumping in with patent claims
on things like
putting the part in a container with a bit of solvent.

I think the smoothing battle is going to hold up progress till things change
with patent suits (and DMCA strictures).

...not to mention the battles over how the printers are assembled/configured
has been heating up too.

 

[gunnusmc03]

No time -- wanna print 'em in bulk.

You might want to get a hold of place that is capable of doing this and consult with them. 3D Printing is a very slow process, we're talking hours instead of minutes to create parts. The ABS material doesn't lend itself well to parts that move and rub against each other as it's fairly brittle.

 

[fulltrack]

Do you have a 3d model? I have a printer and can send you a prototype. Currently have ABS, PLA and Nylon.

 

[madhatte]

I don't, yet. Gotta brush up on Solidworks, but it should be easy enough. I'm thinking now that maybe just the idler needs to be nylon. That should take up all of the metal-on-metal abuse I'm worried about.

 

[fulltrack]

I've had good success modeling mechanical parts in openScad - there are a number of gear librarys. As for the smoothing, abs is easy with a crock pot and a bit of accetone. The other method that would keep cost low is, model it with the 3d printer and spin cast it. Either way, let me know. I'd be happy to print it and drop it in the mail. Our machine is tuned pretty well and produces as good a resolution as you will get from a 3d printer at this point.

edit:
what are the id/od and height of the part you'd need? Is there a shoulder or any steps etc?