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Cutting retaining rings / snap rings for roller chain

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Hi there,

My girlfriend and I are trying to pin the end of roller chain rods to keep the links on since we are creating custom roller chain that is 5" wide. We are essentially creating cross-rod chain. My first thought was to peen the ends of the chain but that makes it very difficult to do without pinching the chain. So I did some research and apparently there are numerous way to terminate the end of a roller chain rod: I've seen drilled holes with cotter pins or very small retaining pins. I've aso thought about retaining rings or snap rings which I think would look the best but I'm under the impression you need a lathe to cut those indentations in the 4mm rod. The chain parts we are using are #40 stainless and the rod is 4mm stainless. Obviously drilling a very small hole on a rod isn't exactly easy either. The other thing I thought about was trying to order pins directly made through US Tsubaki or Diamond chain Co but I think this will mostly likely be very expensive compared to getting 4mm stainless rod and cutting the lengths myself and then drilling/lathing the ends to come up with some kind of retaining method.  There are obviously a ton of different ways to do this. It would be interesting to know if there's a way I can cut the rings in the rods themselves so I can use the standard spring clip type connecting link but I'm guessing I need a metal working lathe and tons and tons of time. Did I mention we have about 18 feet of chain to do!! :unsure:


any ideas?









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Technically, a 4 mm won't fit.  The pins are .156 which is 3.96mm.  I'm surprised you succeeded in getting a 4mm into the bushings as the bore negative tolerance often precludes getting in pins which are that tight.  Pitch tolerance can also be a problem when stacking chain side by side because technically, each chain strand won't match the others.  Pitch tolerances are large enough that any 10 foot section of a # 40 could vary by 1.5 inches and still meet specs.

SOP is often to use a straightened 9 gauge (.148" dia) hard wire as a replacement pin.  It's a little sloppy but unless you are doing a heavy transmission drive, is usually adequate.

You also have a problem regarding the stainless material if you are using the final product as a driving chain.  The joint bearing area and the threshold galling stress of stainless are both low so anything above 135 pounds per standard chain strand will result in pin galling unless heavily and properly lubricated.  With a safety factor, chain companies would usually recommend not exceeding about 80 pounds per strand.

Are you re-inventing the wheel a bit there?  Triple wide (and more) roller chain is already available and would be specified as a 40-3.  One way to get what you want would be to order 40-3 connector links with the snap ring grooves already in place.  Not sure how common that would be in stainless.

Another alternative is to weld washers on the ends of the pins.  This precludes disassembly but is common practice and keeps things together well in use.

I'd need to know more about your intentions for the build-up to offer any more suggestions.  FYI, my business is chain.

Your location isn't specific in OR but you also have an HKK chain warehouse in Wilsonville that might be helpful. 


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Thanks for the reply. Oddly enough my 4mm stainless rods I bought off of ebay are .156 and not 4mm (.1574) so they fit perfectly.

I tried welding a stainless washer onto the stainless rod. Not going to be easily. I'll have to re-configure my tig for very, very light work and then I'll be able to do it much easier without burning through the washer. Still it's going to be very difficult even for a seasoned welder because the rod is so much thicker than the tiny washer and care has to be given to make sure the washer stays at 90dgs to the rod. I suppose I could also find a much thicker washer or even a small stainless bearing. That would be much easier now that I think of it. Or even 4mm tubing cut into little 1/8 or so pieces to weld on.

The final product is going to look like the cross rod chain above and it's for robotics. Sprockets will drive the outer links and over the inner rods will be tank tracks that will go under the chain portion on both sides. I don't think we'll have too much strain on it the chain. It just has to be tightened a bit to get the slack out but it's not going to be under considerable strain otherwise it would start binding up the motors. We are in the desert here so moisture is really low so I'm not too worried about the galling effect.

We actually bought tripple wide stainless 40-3 SS chain, drove the pins out and got all the best links and plates and now we can make our own crossrod chain in the width we see fit.

I'm beginning to think I'll probably have to find some sort of standard pin length already made so I can use spring clips or cotter pins, otherwise welding little bushings on the ends of the stainless pins seems the next easiest way. Trying to set up hundreds of pins on a lathe to cut those grooves seems insane as does trying to drill a little hold dead center in the ends of stainless rods at very precise locations lol

I'm in Terrebonne, OR and there's not a lot of suppliers here in the high desert for this kind of stuff from what I remember

The middle piece on the pics below are 3d printed white plastic and black rubber. I want to make my middle piece out of aluminum or steel, but hopefully from these pics you can get an idea of how people are constructing these tracks. Maybe you can tell me if I'm going at this right or not. Another way that's possible is some type of threaded material inside the inner track and then use machine screws but I didn't really like that idea. I felt like there may be too much slop and not enough stiffness.

Thanks for any help you can give.












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the issue that I would be uncomfortable with is the extra movement in a chain made entirely of flexible links, part of keeping a chain on a cog is the fact that the inner link is a solid unit and the outer link is also a solid unit. the only movement is rotation around the pin that joins the two links. I have run your idea around in my head for several days and I still cant decide how much sideways movement it will have and if the chain will stay on the cogs. What I can say is, if the chain/track is tensioned with a solid tensioner and it does grab a tooth and climb up, something will bend, usually it is the shaft.

Cutting clip grooves is possible, however they need to be the correct width and hardened. With a wide or worn groove, lateral pressure on the clip will bend it over and lever it off.

If it was me I would prefer to use a pair of conveyor style chains and bolt or rivet the tracks on.

Or increase the size of the chain and use a single chain with lugs on both sides of the link


alternatively there is a chain called hollow pin that is designed for custom attachments. If you could find some that is a suitable size it would be possible to fit the tracks with the existing design using a long bolt and nylock nut perhaps. I have a couple of machines that have bolt on attachments on hollow pin chain and they seem to work OK, I have never had to buy replacement chain so I have no idea how hard it is to get.

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9 hours ago, yahoo2 said:



I did look at hollow pin early on and I felt to unsure about whether the plates would pop off the links if they get to much twist or torsion on them. I don't think I saw that attachment chain but that would work. Only thing is if you bolt or rivet plates for treads you have to be careful the track treads stay 90dgs. That is you have to make sure both pieces of chain stay parallel to each other. Maybe welding them would be more secure.

What I'm gonna try as an experiment is to solder on small bushings like these


I got some very low temp solder that supposedly works exceptionally well even at 300dgs F. It should hold the entire assembly very tight, or at least that's the idea. And since it's not a lot of heat I don't have to worry about the chain links warping or distorting. Tig welding put to much heat into the rods and bushings I tried that I was too worried about messing up the chain. But I think I'll have to come up with a middle piece of track like they have in the pics above with the white/black resin.

Hopefully it comes together like it does in my mind lol.

Thanks for the good ideas.

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17 hours ago, Avadon said:


I did look at hollow pin early on and I felt to unsure about whether the plates would pop off the links if they get to much twist or torsion on them.

Only thing is if you bolt or rivet plates for treads you have to be careful the track treads stay 90dgs. That is you have to make sure both pieces of chain stay parallel to each other. Maybe welding them would be more secure.

from memory, if you are looking at #40 from tsubaki the load rating is about 350kg, their hollow pin version would be about half of that.  I seriously doubt that two chains connected with torqued bolts through a track cleat would move at all.

Incidentally the photos above are assembled incorrectly, the track should not span the inner link, it is an extra friction point making the chain harder to drive and it will wear the contacting surfaces as the chain rolls on and off the sprockets, it should be one pin over and spanning the outer link so it is locked solid with the link. I still think cutting a short thread on a long bolt and using a nylock nut and some loctite through a hollow pin chain would be the best option if you are going down that path.

I run a few machines with feeder chains, that is pairs or triple chains with slats bolted between them over a 1 or 2 metre width, the only time I have trouble with them out of square is if I pick up something solid and it levers the chain off one of the sprockets or it is completely worn out and badly adjusted and it jumps a tooth. The ones designed for really rough conditions use a double pitch link and axle covers to avoid stones, sticks, vines, string, wire, green crop, mud and slimy insect guts from building up around the axle and sprockets.

The other issue you might have if you are working in soft powdery conditions is fine dust (not gritty but like talc powder) or mud getting in the chain links pivot bearing, attracting some moisture and rusting the chain solid when the machine is stored. Standard chain will not have a problem if it is lubed but it will look dirty sometimes. if you run it without any lube at all so it looks nice and wash it before you store it or keep it somewhere damp you may have a problem.

Hope it works out.

My post is a bit basic, sorry, I am pushed for time, I gotta slip out and sow some wheat.

P.S. I could be cheeky and suggest looking a tracked dumper for inspiration

Edited by yahoo2
attempt at humour
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