Titanium chain & sprokets

[rubicondsrv]

dose anyone know where i can purchase titanium chain and/or sprockets i have found a manufactuer of titanium chain but cand find where to buy if from.

[Greg Perkins]

...what for?????? ?????....


whats wrong with standard #35 chain???? i really dont see the need for titanium chain and sprockets...a bit overkill if you ask me...

[Max Lobovsky]

IIRC, titanium isn't that much better strength-to-weight wise than steel. It is probably better worth your time to efficiently lighten your sprockets (something you likely won't be doing with titanium because it is very hard to machine).

[Cory]

If you want titanium chain and sprockets, you're going to blow almost the entire cost of your robot right there.

Try looking at nylon sprockets. They're plenty light and then won't cost you an arm and a leg, and they should hold up unless you're putting a ton of torque through them.

I'm not sure you'd even save enough weight using titanium over steel that it would be worth it for the money.

[Tristan Lall]

Here. (Scroll down to "Chain".) It costs $700 (AUD) for one bicycle chain; plan on using only 73% of that, if you want to stay within the cost limit.

Alternatively, Tsubaki sells some (scroll down to "TI Titanium Roller Chain") that might just conform to ANSI specs. Contact any of their local distributors (on their site) for pricing and lead time. If I might hazard a guess, they're going to say that it's a special order with a minimum quantity, costs about $200 (CAD) per foot, and that they will need 14-20 weeks to process the order. You might have better luck, but I doubt it.

While I'm in a Tsubaki state of mind, let me point you to their catalogue, which contains a lot of good engineering information. Section 1, pages A-6 and A-7 (in Acrobat, 17 and 18) have horsepower charts for #25 and #35 chain; consult those--you might be able to get away with #25, instead of #35, if that's what you had in mind. That's a significant weight savings, if it can be done.

[Max Lobovsky]

Notice how Tsubaki titanium chain is marketed as high temperature and anti corrosive, not high strength. Titanium chain is a bad idea.

[Cory]

Titanium sprockets and chain are commonly used in bicycles. There's a few problems with that though. It's still expensive, the chain and sprockets are slightly narrower than #35 chain, so you aren't going to be able to bum replacements off someone at a competition.

Also, they come in very limited tooth counts. You'd also have to make an adapter to mount them to a shaft/wheel with, since they mount onto the cassette very differently than you would mount a sprocket to a shaft in FIRST.

Overall, really not worth the effort. Just use #25 chain and sprockets

[edit]
The chain alone is going to run you $350 each, and you'll need 4 of them.

The cassette is $150 each and you'd need 4 of them assuming you want to make a 4 WD robot.

And then you'd need to buy a set of chainrings, which are also going to cost you a pretty penny.

There's no easy or cheap way to do it

[Biff]

Originally Posted by Cory

If you want titanium chain and sprockets, you're going to blow almost the entire cost of your robot right there.

Try looking at nylon sprockets. They're plenty light and then won't cost you an arm and a leg, and they should hold up unless you're putting a ton of torque through them.

I'm not sure you'd even save enough weight using titanium over steel that it would be worth it for the money.

We used nylon sprockets last year and on final drive they were a disaster. Closer to the motors works OK, If you really want to save weight, There is a sprocket builder in mechanical desktop. Then get aluminum water jetted, the same profile in steel is about 4 times heaver, and nylon is about 1 oz heaver for a 45 tooth #35. Search the web for a how to streaming tutorial on mechanical desk top and inventor sprockets.

[Derek Bessette]

We used nylon sprockets on our prototype over the fall. The prototype used a fisher price and a CIM motor on each side of the robot in a six wheel drive configuration. We used AMshifters to give us a top speed of 10 ft/sec in high and about 4 ft/sec in low (off the top of my head). I don't have the torque numbers in front of me but I would say it is comparable to any sort of forces most teams would see on their drive train. We bolted nylon sprockets on the four corner wheels (less load than the center wheels usually). We had 180 degrees of tooth engagement on the sprockets which were 30 tooth and 35 pitch. After a lot of hard testing we had no problems with these sprockets. Not a single tooth was broken and there wasn't any excessive wear. We are not sure if we had any efficiency loss from the nylon sprockets yet,

Note: In the end we decided to lighten steel sprockets for our drive system just to be safe.

If your really trying to save weight I would look at nylon or aluminum sprockets. We bought the nylon sprockets (part number 6793K135) from Mcmaster-Carr. We also have bought aluminum sprockets from a local supplier for Azusa . These sprockets are made for go-karts and look really good and strong.

Hope this helps,
Good Luck!!

[JVN]

Originally Posted by Derek Bessette

...We also have bought aluminum sprockets from a local supplier for Azusa . These sprockets are made for go-karts and look really good and strong.

We also use Azusa.
Good stuff.

For the uninformed, check this out:
http://www.chiefdelphi.com/forums/showthread.php?t=24246&highlight=aluminum+sprocket s

Kudos to Joe for sharing this last year. I'm sure lots of people are still reaping the benefits.

-JV

[Peter Matteson]

Just a little more info on titanium sprockets.

Shimano Dura-Ace ten speed cassettes have 4 Ti sprockets, the four largest sizes vary depending on the cassette. They cost ~$150 (for 11-23) to ~$170 (12-27). This is cost prohibitive very quickly.

Also the 7075 Al sprockets are hard-coat anodized (class III) for durability while the Ti is nickle coated for the same reason.

However you may be able to get Ti, and definitely Al bike chainrings on sale from some of these places. Think prelightened sprockets. Just don't bogart the Dura-Ace on me Also any one who builds a robot with Campy should win the form over function competition immeadiatly.

You can get these from any number of bike cataloges:
www.worldcycling.com
www.coloradocyclist.com
www.supergo.com
www.nashbar.com
www.performancebike.com

[roboticscom13]

We used nylon sprockets for our robot's drivetrain last year. We got into pushing matches and we ran at high speeds and they were perfectly fine. If you are concerened that much about wieght i would say use the nylon sprockets. We used steel sprockets in the '02 competition and they were exceedingly heavy even machined out. We also had a couple of them fail. We incorporated nylon sprockets in the same drive train but for last year and they worked perfectly. I would use nylon sprockets for the drivetrain, and then like alreadly said if there are high ammounts of torque needed then you should do calculations to see if it would be beneficial to go for steel sprockets.

[Adam Y.]

Originally Posted by Max Lobovsky

Notice how Tsubaki titanium chain is marketed as high temperature and anti corrosive, not high strength. Titanium chain is a bad idea.

Actually there are two versions of titanium. I believe one is just as strong as aluminum and is advertisted as high temerature and anticorrosive while the other version is just advertised as strong.

[Holtzman]

Originally Posted by Dzdconfusd

Just a little more info on titanium sprockets.

Shimano Dura-Ace ten speed cassettes have 4 Ti sprockets, the four largest sizes vary depending on the cassette. They cost ~$150 (for 11-23) to ~$170 (12-27). This is cost prohibitive very quickly.

You should also note, that these bicycle sprockets are designed to take torque in one direction only. Ex, you don't ride a bike back wards. If you look closely, the tooth profile is optimized for load in the pedaling direction. It is much more obvious on the front chain rings.

These sprockets would also be very hard to work with. All the major bicycle component manufactures have there rear sprockets fitted on a non-standard spline, that would be VERY difficult to machine yourself. Theres also not very much material left over do drill your own mounting holes either.

The front chain-rings would be much more easily adapted. Most road chain rings fit on a standard 130mm bolt circle, and the higher quality ones are very light. Mountain bike chain rings are smaller in size, and also have a smaller bolt diameter.(which i don't know off the top of my head) On the other hand you still limited to bicycle chain, which although is 1/2", is much narrower than standard ANSI chain. You also need special connecting pins, to change the chain length, and a different chain tool. Also, you cannot get half-links for it.

In summary, it is my opinion that, although very light, high-performance bicycle sprockets are more hassle than their worth. You can get standard aluminum sprockets, and just lighten them yourselves, and they will be just as light as bicycle sprockets, and a whole lot easier to work with.

[Peter Matteson]

Originally Posted by Holtzman

You should also note, that these bicycle sprockets are designed to take torque in one direction only. Ex, you don't ride a bike back wards. If you look closely, the tooth profile is optimized for load in the pedaling direction. It is much more obvious on the front chain rings.

Not true. They only see it in one direction. The teeth however are ground to help shifting in the normal direction of operation. See the below link to see what I mean.
http://www.dura-ace.com/publish/cont...ive_train.html

Originally Posted by Holtzman

These sprockets would also be very hard to work with. All the major bicycle component manufactures have there rear sprockets fitted on a non-standard spline, that would be VERY difficult to machine yourself. Theres also not very much material left over do drill your own mounting holes either.

This is true and I purposely didn't mention it before. It's also a PITA to take apart a cassette. Which is why I pointed to front chainrings.

Originally Posted by Holtzman

The front chain-rings would be much more easily adapted. Most road chain rings fit on a standard 130mm bold circle, and the higher quality ones are very light. Mountain bike chain rings are smaller in size, and also have a smaller bold diameter.(which i don't know off the top of my head) On the other hand you still limited to bicycle chain, which although is 1/2", is much narrower than standard ANSI chain. You also need special connecting pins, to change the chain length, and a different chain tool. Also, you cannot get half-links for it.

Shimano Std Chainring BOLT circle = 130mm
Campagnolo Std Chainring BOLT circle = 135mm

Yes they use a 1/2" pitch chain. No the chaintools aren't that special just smaller. No special parts are required you just add or remove links. Bike chains don't use master links. Yeah they make really narrow chain for the 10-speed cassettes that doesn't even work with the 9-speed cassettes. The advantage is you can get it at any bike shop.