Hex Axle- How to

[Aren Siekmeier]

Originally Posted by Chris is me

No and no. I don't see what we'd need a rotary broach for?

I guess I was under the impression a rotary broach gave you more options (which it still does: not cutting all the way through, using it on more standard machines...), but on reading more about it it looks like they're actually worse in some cases. It all works out since it sounds like normal ones are cheaper...

[AdamHeard]

Originally Posted by compwiztobe

I guess I was under the impression a rotary broach gave you more options (which it still does: not cutting all the way through, using it on more standard machines...), but on reading more about it it looks like they're actually worse in some cases. It all works out since it sounds like normal ones are cheaper...

Blind broaching isn't terribly useful for what we do, you'd need to retain the part axially in some other operation.

We have a full set of push broaches, and use them for hundreds of holes a year without issue.

For frc, I see the only real advantage of rotary broaches being the ability to run them on a cnc mill for the teams that have an in house machine.

[AustinSchuh]

I got a chance to use a 5C hex collet at school, and it was very nice. I would highly recommend one.

[nick_sheets]

http://www.amazon.com/5C-Collet-Bloc...&n=228013&s=hi

We seem to have 5C collet at our small school shop and we seem to have the set linked above. How do you use this on the mill or lathe? We have a very very very small shop with 1 mill and a lathe. So this would be very handy!!!!!

What is the tool to the right of the picture?

Thank you!

[Karibou]

Originally Posted by nick_sheets

http://www.amazon.com/5C-Collet-Bloc...&n=228013&s=hi

We seem to have 5C collet at our small school shop and we seem to have the set linked above. How do you use this on the mill or lathe? We have a very very very small shop with 1 mill and a lathe. So this would be very handy!!!!!

What is the tool to the right of the picture?

Thank you!

I've never seen them before, but it looks like those would be used on the mill:
http://bbs.homeshopmachinist.net/showthread.php?t=36517
(There's a nice picture there that should make a lot of sense if you've had any machining experience)
I don't know for sure, and maybe someone who actually has used these before can give a more educated answer, but my best guess would be that you slide the collet inside the block, insert the piece of hex shaft, and then use the closer ring on the back to tighten the collet around the metal in addition to keeping it from sliding out of the block while in use.*

*again, best guess. If someone knows for sure how to use these, please correct me, because I'm curious as well.

[Chris is me]

You install a collet on a lathe or mill to secure parts, as opposed to something like a three jaw chuck. The cone shape of the collet squeezes the work piece in place as it is tightened into the lathe or mill.

I'd think a hex collet would probably be used on a lathe. Can't see much utility in replacing your mill's tooling with a spinning hex shaft.

[sanddrag]

Originally Posted by Chris is me

You install a collet on a lathe or mill to secure parts, as opposed to something like a three jaw chuck. The cone shape of the collet squeezes the work piece in place as it is tightened into the lathe or mill.

I'd think a hex collet would probably be used on a lathe. Can't see much utility in replacing your mill's tooling with a spinning hex shaft.

The idea is to place a collet in a hexagonal shaped collet holder, which is then placed in a mill vise. This lets you index the work piece to six accurate positions for milling the sides of the hex into round stock, without the need for a dividing head or indexer.

[Chris is me]

Originally Posted by sanddrag

The idea is to place a collet in a hexagonal shaped collet holder, which is then placed in a mill vise. This lets you index the work piece to six accurate positions for milling the sides of the hex into round stock, without the need for a dividing head or indexer.

Oh, I forgot to read the context of the thread around it and just saw a perfectly normal looking collet. Thanks for the informative post.

[Andrew Schreiber]

Originally Posted by compwiztobe

(which it still does: not cutting all the way through, using it on more standard machines...)

Specifically the standard machines part... Could you elaborate on that? Personally, every shop I've ever worked in had an arbor press in house and that is how we always broached. Is this not standard equipment for most teams?

[JesseK]

Originally Posted by Andrew Schreiber

Specifically the standard machines part... Could you elaborate on that? Personally, every shop I've ever worked in had an arbor press in house and that is how we always broached. Is this not standard equipment for most teams?

Eh, there's no "recommended big tools for your shop" section anywhere in a manual or update (etc) from FIRST. So I doubt it's 'standard' unless there's a mentor or sponsor who knows what they're doing.

[Andrew Schreiber]

Originally Posted by JesseK

Eh, there's no "recommended big tools for your shop" section anywhere in a manual or update (etc) from FIRST. So I doubt it's 'standard' unless there's a mentor or sponsor who knows what they're doing.

Perhaps 'standard' was the wrong word. Perhaps 'common' would have been better.

[thefro526]

Quick suggestion if you're looking to play with hex shaft:

Contact a local metal supplier and ask if you can look through their scrap. We have a supplier down the road that has dozens of random pieces of stock that are left over from cutting down 20' lengths. We got quite a few short (smaller than 3') pieces of hex last year for nothing.

[Chris is me]

Originally Posted by thefro526

Quick suggestion if you're looking to play with hex shaft:

Contact a local metal supplier and ask if you can look through their scrap. We have a supplier down the road that has dozens of random pieces of stock that are left over from cutting down 20' lengths. We got quite a few short (smaller than 3') pieces of hex last year for nothing.

Be aware that if you do this, you might end up with 6061 hex axles. Then you'll suffer months of mockery by all of your friends because of a silly drivetrain failure.

...just a heads up.

[JesseK]

Originally Posted by Chris is me

Be aware that if you do this, you might end up with 6061 hex axles. Then you'll suffer months of mockery by all of your friends because of a silly drivetrain failure.

...just a heads up.

There are no silly drive train failures except for those that are consistently repeated, but it's a very good point about 6061 for use as cantilevered axles.

[kaliken]

Originally Posted by Chris is me

Be aware that if you do this, you might end up with 6061 hex axles. Then you'll suffer months of mockery by all of your friends because of a silly drivetrain failure.

...just a heads up.

6061 is a fine alloy to use. You just need to be smart in the design and do the math to prove you are within proper yield safety margins. Thus cantilevering may not be the best idea, but I can vouch that using 6061 in a simply supported setup has worked fine for us for the past 5 years.

Also as a heads up. For purchasing hex stock from McMaster or any other metal supply store, we have found that the stock is usually oversized by a small amount. This means our 0.5" hex broach is a little too small. A small amount of sanding on each side solves the problem quite readily.