Hex Sprockets

[rahilm]

We have some bad experiences with key shaft in the past, so we're looking to switch to hex. Looking online, I can't seem to find any supplier that sells 1/2" hex bore sprockets. Anyone know of a supplier?

[sgreco]

I don't know of any. You could buy sprockets with smaller bores than you want then Hex broach the yourself.

[gorrilla]

We have some bad experiences with key shaft in the past, so we're looking to switch to hex. Looking online, I can't seem to find any supplier that sells 1/2" hex bore sprockets. Anyone know of a supplier?

You could bolt a sprocket onto on of AndyMarks hex-hubs.
What size sprockets are you thinking about?

[rahilm]

We were thinking about doing the broaches ourselves, but thats $500+ for an arbor press, and then another $200 for the broach.

You could bolt a sprocket onto on of AndyMarks hex-hubs.
What size sprockets are you thinking about?

For now we were looking at some pretty small sprockets, #25 chain, 22 teeth, about 1.75" diameter.

[548swimmer]

For now we were looking at some pretty small sprockets, #25 chain, 22 teeth, about 1.75" diameter.

Any reason you can't scale the sprockets up so that you can bolt them on?

[AdamHeard]

Any reason you can't scale the sprockets up so that you can bolt them on?

This is the ideal sprocket size and bore for a west coast drive.

254 and us make lots and lots of sprockets that size during season from the AM 22T #25 aluminum sprockets, we'd be willing to do a batch for you guys next season if you cover the cost. I'm sure 254 would as well.

[rahilm]

This is the ideal sprocket size and bore for a west coast drive.

254 and us make lots and lots of sprockets that size during season from the AM 22T #25 aluminum sprockets, we'd be willing to do a batch for you guys next season if you cover the cost. I'm sure 254 would as well.

We're actually using it for a different purpose other than the drivetrain.

We can't scale up the sprockets because we have very little clearance, so anything even slightly bigger wouldn't work.

[Chris is me]

I would either get a hex broach (Pretty useful over time if you make a lot of wheels and sprockets) or take up 973's offer. I looked around all last year and couldn't find any.

[mikelowry]

We were thinking about doing the broaches ourselves, but thats $500+ for an arbor press, and then another $200 for the broach.


Broaching can be done by hand with a lathe or even a drill press if you have one of those.

[Andy Baker]

For now we were looking at some pretty small sprockets, #25 chain, 22 teeth, about 1.75" diameter.

We are getting many requests for these hex-broached sprockets. We will start offering these early this fall or later this summer.

Sincerely,
Andy

[MrForbes]

I like Andy's solution :)

but $500 for an arbor press....hmmmm.....

http://www.harborfreight.com/6-ton-a-frame-bench-shop-press-1666.html

[R.C.]

I like Andy's solution :)

but $500 for an arbor press....hmmmm.....

http://www.harborfreight.com/6-ton-a-frame-bench-shop-press-1666.html

And you have enough money left over for a 1/2" broach. It is extremely handy to be able to broach in house. :D

-RC

[rahilm]

I like Andy's solution :)

but $500 for an arbor press....hmmmm.....

http://www.harborfreight.com/6-ton-a-frame-bench-shop-press-1666.html

All the 1/2" broaches I'm seeing online are almost a foot in length though, so I'm not sure how that would work with that press, since it has 4" max working distance.

[MrForbes]

It would take some extra work, you'd have to move the press plate down to start, and then move it up as you go. Or make some different length rods so you could just add them as you go. They have some larger presses that give you more room to work, although any hydraulic press with a bottle jack has a relatively short stroke. You could replace the jack with one from an engine hoist, although the cost goes up.

[Cory]

I like Andy's solution :)

but $500 for an arbor press....hmmmm.....

http://www.harborfreight.com/6-ton-a-frame-bench-shop-press-1666.html

It doesn't look like there's any possible way to get enough travel out of that thing to start the broach.

The hydraulic ram arbor presses are terrible for hex broaching, for a number of reasons.

We used one in 2007 and 2008 and always experienced mediocre results.

The ram is not supported in any meaningful manner on most presses (likely to just involve two tubes running inside two other tubes, leading to a lot of slop. With hex broaching the alignment of the broach to the workpiece is absolutely critical and this slop killed any chance of the broach running true.

It's also a huge pain to have to constantly be raising the table and cranking on the jack. They're really the wrong tool for the job. Nobody needs a 6 or 12 ton press for FIRST purposes.

Mechanical presses in the 2-3 ton range can be had for $150-200. We bought a nice Palmgren 5T press a few years ago for $300 something on sale from Enco. It's definitely worth spending a bit more money to get a quality arbor press. It's such a useful tool. We use ours multiple times per day during the build season.

[Akash Rastogi]

It doesn't look like there's any possible way to get enough travel out of that thing to start the broach.

The hydraulic ram arbor presses are terrible for hex broaching, for a number of reasons.

We used one in 2007 and 2008 and always experienced mediocre results.

The ram is not supported in any meaningful manner on most presses (likely to just involve two tubes running inside two other tubes, leading to a lot of slop. With hex broaching the alignment of the broach to the workpiece is absolutely critical and this slop killed any chance of the broach running true.

It's also a huge pain to have to constantly be raising the table and cranking on the jack. They're really the wrong tool for the job. Nobody needs a 6 or 12 ton press for FIRST purposes.

Mechanical presses in the 2-3 ton range can be had for $150-200. We bought a nice Palmgren 5T press a few years ago for $300 something on sale from Enco. It's definitely worth spending a bit more money to get a quality arbor press. It's such a useful tool. We use ours multiple times per day during the build season.


What hex broaches (brand, price, etc.) would you recommend? 1/2 and 3/8

[Cory]

What hex broaches (brand, price, etc.) would you recommend? 1/2 and 3/8

I think the only real option you have is Dumont. When we bought ours a .375 hex was about $120 and a 1/2" about $175-200.