Installing chain tensioner. How do you deal with the flange adjacent to where the pin is installed

The Thrifty Bot, Andy Mark, and WCP turnbuckle style chain tensioners all have a little raised area or flange adjacent to where the chain link is attached that seems to prevent it fitting into the chain tool and getting the plates secured on the pin that goes through the tensioner hole. We can’t seem to get a solid connection there. We’ve tried a vice and pliers but it still looks pretty jank. Any Suggestions? Thanks.

Use a master link

It would be nice if the tool or turnbuckle design allowed it to sit flat in the chain tool channel, but with some care we were able to align the pin hole of the turnbuckle piece with the chain links and press in the pin with the turnbuckle piece sticking approximately straight out of the chain tool (90 degrees or so relative to the way the chain lays).

Is it the easiest process? No, but it can be done with a careful hand, and possibly a second set of hands for support.


We were told, in rather emphatic terms, never to use master links. Is this an old roboticist tail?

Thanks. We tried that but the part of the chain plate closest to the turnbuckle remained a little bent and not fully set.

There’s never, and then there’s NEVER :slight_smile: Personally, I avoid master links as much as possible, but this is one situation where they’re appropriate - call it an exception to the rule :slight_smile:

The problem with master links is failure. The plate that secures them on can rub on something and be run off, causing the link to fail. So in the case of something like a drive train or intake, pressing the pin back in provides a much more secure and failure-free option. In this case, you have limited range of motion, and the turnbuckle, being bigger than the chain, means you need to leave sufficient room around the chain that nothing should risk interfering with it. I would feel fine using a master link in this situation.

I found that it is possible with the VEX chain tool, it’s just not the easiest thing to install. Usually I’d use the secondary spot and push the pin back thru the chain attachment bolt. You can also swap the two and use the one that has a pin to push it a little further than the non-pin side allows for.

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That’s the chain tool we have but we couldn’t get it aligned like that. Maybe we’ll try again. Thanks.

It’s tricky, takes some patience and a steady hand. The chain stuff is probably the most difficult part of the Thrifty Elevator build IMO. After you do it multiple times it’s not too bad but it takes time.

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Almost all the popular #25 chain tools can push the pin back most of the way onto the tensioner, using a groove lock/channel lock wrench to further push it in, sandwich the chain with an M3 nut in the back to allow the chain pin to be centered with the chain. the one solution I found to finish the work.


I’m in the camp if the load is light enough for an in-line tensioner then I am fine with master links. If it is a real high load then I am against them.

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I can confirm this also can be done with the Rev chain tool.

We have 4 Rev Turnbuckles on our practice bot, and 4 TTB Turnbuckles on our comp bot. No master links required.

It is a little finicky, but I didn’t think it was too bad.

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