pic: Ultimate chain tool project

[Bryce2471]

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[billbo911]

Some things to consider:
Deep pockets with fairly small area need a lot of consideration paid to chip clearing.
Chain breakers put a substantial load on the threads. If using 6061, you may want to think about designing it for a Helicoil.
To run this on your Tormach, you will be using fairly small dia. end mills. To keep your chip load proper, this part will take a lot of time to process.

This is a really good training exercize. It will teach you a lot about setting up and milling small parts.

[Bryce2471]

Originally Posted by billbo911

Some things to consider:
Deep pockets with fairly small area need a lot of consideration paid to chip clearing.

True. Should be a good test for rout planing and coolant systems.

Chain breakers put a substantial load on the threads. If using 6061, you may want to think about designing it for a Helicoil.

We've got some 7075 we're planning to use but if it's too tough to machine, helicoil is a good suggestion.

To run this on your Tormach, you will be using fairly small dia. end mills. To keep your chip load proper, this part will take a lot of time to process.

Very true.

This is a really good training exercize. It will teach you a lot about setting up and milling small parts.

That's good I hope they learn a lot.

[RoboChair]

Originally Posted by Bryce2471

We've got some 7075 we're planning to use but if it's too tough to machine, helicoil is a good suggestion.

7075 machines like a dream. Honestly I would say it machines much better than 6061, pity that it's so expensive.

[billbo911]

Originally Posted by RoboChair

7075 machines like a dream. Honestly I would say it machines much better than 6061, pity that it's so expensive.

+1, on both comments.

[aldaeron]

I would consider the next step up for re-usable fasteners - a keyed insert. The brand name I know is Keensert. These are much more robust inserts, but do require some specialty tooling. I would see if a local machine shop would lend the tooling to you. This was our standard insert for aluminum vibration tooling to allow easy install of control accelerometers. We found that using tanged or tangless helicoils over and over again was a bad idea and once we switched to Keenserts the problem went away.

-matto-

[topgun]

A couple of points:
1) Why not machine it out of 1018 steel? Tormach can handle steel.
2) Why do you want to push the pin out? I made one for my team and it's set to push the pin out enough so you can break the chain while leaving the pin in. Then you have a pin ready to push right back in. This is much more secure than any connecting link you would use.
3) I used an injector pin for the part that is actually pushing against the chain pin. These are very hard and won't mushroom out, plus you can get them sized to fit thru the pin hole.
4) Make sure you have enough leverage available on the handle to actually move the pin. We used a shcs so we can put a long allen wrench in it or even use a drill with a hex bit.

[MechEng83]

Some additional comments I didn't see written:

I'd recommend you use fine thread rather than coarse thread. The screw will be easier to turn.

Are you machining the all thread down to the point? If I understood your description, it's case hardened, but that won't help you if you machine away the case. For our custom #35 chain tool (and the replacement we used for the #25 that broke) we used a hardened dowel pin inserted into the end of the screw.

[Chris is me]

Originally Posted by RoboChair

7075 machines like a dream. Honestly I would say it machines much better than 6061, pity that it's so expensive.

I think the concern isn't with the difficulty of cutting the material, but with the strength of the threads tapped into the block. If these strip, a helicoil is the logical next step.

-

I'm excited to see the development of not only an improved 25 chain break, but a 35 chain equivalent. Do you think instead of milling square protrusions, you could just press roll pins into the block to constrain the chain? This makes manufacturing much easier for you, and it avoids causing overconstraint by limiting the points of contact with the chain.

[Bryce2471]

Originally Posted by topgun

A couple of points:
1) Why not machine it out of 1018 steel? Tormach can handle steel.
2) Why do you want to push the pin out? I made one for my team and it's set to push the pin out enough so you can break the chain while leaving the pin in. Then you have a pin ready to push right back in. This is much more secure than any connecting link you would use.
3) I used an injector pin for the part that is actually pushing against the chain pin. These are very hard and won't mushroom out, plus you can get them sized to fit thru the pin hole.
4) Make sure you have enough leverage available on the handle to actually move the pin. We used a shcs so we can put a long allen wrench in it or even use a drill with a hex bit.

1. Because we have some 7075 to use, and who else can say they have a custom chain tool cut from aerospace grade aluminum?
2.Because, as stated in the description, this tool can be used to build chain (put the pin back in) if the pin is removed.
3. Thanks for the suggestion, I might look into that, but we have the all-thread and hardening compound on hand, so we'll probably start with that.
4. Good point. The handle is home made, so we could easily put a longer peace of rod in.

Originally Posted by MechEng83

Some additional comments I didn't see written:

I'd recommend you use fine thread rather than coarse thread. The screw will be easier to turn.

Are you machining the all thread down to the point? If I understood your description, it's case hardened, but that won't help you if you machine away the case. For our custom #35 chain tool (and the replacement we used for the #25 that broke) we used a hardened dowel pin inserted into the end of the screw.

The threads chosen were the finest threads of the correct size that we have a tap for.

Yes, I plan to machine the all-thread down to form the mandrel, but the case hardening will take place after that.

Originally Posted by Chris is me

I think the concern isn't with the difficulty of cutting the material, but with the strength of the threads tapped into the block. If these strip, a helicoil is the logical next step.

-

I'm excited to see the development of not only an improved 25 chain break, but a 35 chain equivalent. Do you think instead of milling square protrusions, you could just press roll pins into the block to constrain the chain? This makes manufacturing much easier for you, and it avoids causing overconstraint by limiting the points of contact with the chain.

Both machining the block and the thread strength are a concern.

I think using roll pins is a great idea, but we don't have the size we would need on hand, so the first one will probably be cut as shown.

[asid61]

Originally Posted by Bryce2471

1. Because we have some 7075 to use, and who else can say they have a custom chain tool cut from aerospace grade aluminum?
2.Because, as stated in the description, this tool can be used to build chain (put the pin back in) if the pin is removed.
3. Thanks for the suggestion, I might look into that, but we have the all-thread and hardening compound on hand, so we'll probably start with that.
4. Good point. The handle is home made, so we could easily put a longer peace of rod in.

I believe they meant sizing the pocket such that you can only press the pin out enough to have a little bit left over. That way, you never push the pin out all the way and subsequently be unable to push it back in, which is the most common failure that people seem to have with these.
Also, for rebuilding, I know that the Dark Soul tool has a very wide mandrel for pushing the pins back in. Have you thought about incorporating that rather than relying on the same pin to reassemble?

[Bryce2471]

Originally Posted by asid61

I believe they meant sizing the pocket such that you can only press the pin out enough to have a little bit left over. That way, you never push the pin out all the way and subsequently be unable to push it back in, which is the most common failure that people seem to have with these.

I don't know if you already got this or not, but this tool is hopefully designed such that it can press a pin back into place after it has been entirely removed.
Are you suggesting that it would be better to design for pushing a pin in that has only been partially removed? Maybe that would be easier.

Also, for rebuilding, I know that the Dark Soul tool has a very wide mandrel for pushing the pins back in. Have you thought about incorporating that rather than relying on the same pin to reassemble?

Yes, I have thought about this. Testing should show if it is helpful or not.

[Steven Smith]

Originally Posted by Bryce2471

I don't know if you already got this or not, but this tool is hopefully designed such that it can press a pin back into place after it has been entirely removed.
Are you suggesting that it would be better to design for pushing a pin in that has only been partially removed?

Yup, the DarkSoul tool is sized such that there is a pocket that generates a hard stop when the pin is hanging in just the outer link. This frees the chain to separate, and the pin stays stuck in the outer link.

It can be a little tricky otherwise to align the pin back into the hole for the outer link such that when you apply force it goes in, versus binding up slightly crooked. Leaving the pin in the link makes this a non-issue.

[Bryce2471]

Originally Posted by Steven Smith

Yup, the DarkSoul tool is sized such that there is a pocket that generates a hard stop when the pin is hanging in just the outer link. This frees the chain to separate, and the pin stays stuck in the outer link.

It can be a little tricky otherwise to align the pin back into the hole for the outer link such that when you apply force it goes in, versus binding up slightly crooked. Leaving the pin in the link makes this a non-issue.

Understand how that process works. I have done it before (although not with a dark soul tool). I just thought that designing a tool that could reassemble a pin after it was entirely removed would be an improvement.

The idea of the current design is that it would have a channel for the old pin to be loaded into, such that the pin would automatically be aligned by the tool.

Are you saying that this design would not work as intended, or would not be an improvement? I guess I'm not sure why people think pressing the pin part way out is a better solution, when it requires a certain width of chain, and that the pin does not accidentally fall out.

[Chris is me]

Originally Posted by Bryce2471

Understand how that process works. I have done it before (although not with a dark soul tool). I just thought that designing a tool that could reassemble a pin after it was entirely removed would be an improvement.

The idea of the current design is that it would have a channel for the old pin to be loaded into, such that the pin would automatically be aligned by the tool.

Are you saying that this design would not work as intended, or would not be an improvement? I guess I'm not sure why people think pressing the pin part way out is a better solution, when it requires a certain width of chain, and that the pin does not accidentally fall out.

It is a lot harder to get the pin started and properly aligned, without deforming the pin / hole / chain link, if it is fully removed from the chain. It doesn't really require "a certain width of chain" any more than a size specific chain breaker already does (like these, which require 25 or 35 chain). The pin doesn't fall out that easily but you do have to be a little careful.

Not saying this wouldn't work, though. Maybe you can machine a matching block that slips into the pocket with the relief / hardstop set for the right distance to allow this? That way you have a tool that can do both partial and full removal.