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Connecting Link; 3/8" Chain

Connecting Link; 3/8" Chain

Connecting Link; 3/8" Chain

I had this posted over at the gear and pulley group, but didn't get any replies so I thought I'd try this group.
I'm looking for a full strength rated connecting link for 3/8" Grade 100 chain that will fit in the pockets of this chain wheel.
This is for a close loop system for moving carts though an assembly line.
I'm making the drive with the chain wheel and the customer is somehow making the connection, I assume by welding a link that they have cut and welded back into place.
The Figure 8 connectors are too big for this application.
In the marine industry we use Stud Link chain and there are Kenter links that work with the windlass, but that type of chain starts at 3/4".
I've been looking PEWAG chain and accessories, but they only go down to 22mm.
Any leads would be greatly appreciated.
Best regards, David

RE: Connecting Link; 3/8" Chain

I know of great options up through 1/4", btu 3/8" in interesting.
What is wrong with a pin break tool, just push a pin most of the way out and then make up the chain and push it back in.
What does Diamond sell for this application?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Connecting Link; 3/8" Chain

EdStainless, What you are describing sounds like instructions for Roller Chain.
I'm working with Coil chain used for lifting and such.

RE: Connecting Link; 3/8" Chain

Same problem as previous requests - the only way to get the strength on Grade 100 chain is to have solid welded links. Alignment pins, bolt holes, screw holes, any holes of any kind to join pieces will drop the strength of the joining link too far unless the section of the link can be far larger than the base link. Which with that drum/wheel, it cannot be.

Were it possible the chain makers would sell them. Buy chain in 100 ft or 500 pound increments and buy links to make whatever length you wanted. That the chain makers don't do that is evidence they can't. That no one else that makes such links makes what you want suggests is isn't possible - this is not rocket science. Either fitting into that space or producing one that is affordable (Perhaps someone has a $1000 maraging steel link) is eliminating the item from the market.

Design a chain wheel that will work with available links or set up an operation for welding chain loops for your customers.

RE: Connecting Link; 3/8" Chain

Does the chain slip if a figure-8 connector goes across the windlass, or do the remaining links keep enough grip to let it pass? Or are there issues with the larger connector link allow lateral slip that "de-rails" the chain?

I doubt you will find any information about joining Gr 100 chain, it's an alloy steel and welding it would ruin the temper adjacent to the weld and lower the strength - no stateside manufacturer is going to help, because they make OSHA/ANSI/etc. compliant products that must meet strength and safety standards. It sounds like your customer is making it work, probably because they don't really need the full strength of the Gr 100 chain, but it has better fatigue and wear resistance, and breaking the welded link occasionally is just par for the course for them?

RE: Connecting Link; 3/8" Chain

I have welders in house that I know would have no problem welding a link back together, but we also have equipment to follow a weld procedure.
The end users that I have been supplying re-placement machines to have somehow manage to make the connection for a long time now, the pocket wheel is from another company that they have been using for years also.
We are mainly in the marine business, but somehow one of our capstans turned out to be a good replacement for the manufactured home business, so I'm on a learning curve, as I've been approached to supply complete systems for new plants.
I'd rather not rely on a field weld making the connection.
For Stud link anchor chain, a Kenter Link is our go to for linking shots of chain.
I was speaking to an engineer from the chain company the other day about them making a continuous loop, but they are limited to 50' and I'm looking for 400'.

RE: Connecting Link; 3/8" Chain

LittleInch, right idea, but the 2,700# WWL is way below the 8,800 of the chain.
Based on what they have given me for weight, I calculated a pull of about 7,600#

btrueblood, as this is a new market that seems to have found us, I haven't been able to experiment with the pocket wheel that they have been using.
I've just been buying it from the guy that has been supplying them for many years.
This drive system is in many of their plants, so I'm trying to stay with what they have since they first came to me for replacement parts.
The engineer at the chain company thinks he recalls a company that does make what I'm looking for, but he needs to see if he can locate the source he saw.
Thank you for your input.
Keep it coming.
Best regards, David

RE: Connecting Link; 3/8" Chain

I wonder what limits them to 50', is it the size of heat treatment ovens?

hmm, not necessarily, this video (closer to the end) shows Q+T chain being produced in a continuous process...


RE: Connecting Link; 3/8" Chain

The chain companies also have pull testers to proof load the chain.

I would not and did not suggest field welds.

RE: Connecting Link; 3/8" Chain

btrueblood, they only have enough room to stretch out that much to get all of the twist out. At the end users place, they do.
I believe that the links are heat treated just as soon as they are welded, it's been awhile since I've watched video.
The massive Stud link process is amazing.

3DDave, Hence my search for the mythical chain link. LOL
In house we have many welders with unlimited thickness NAVSEA / AWS welding certificates.
This assembly is kept above 300deg for the next 3 months of welding after the root passes have been X-rayed.
Love the new induction heaters.

RE: Connecting Link; 3/8" Chain

hendersdc, Yes, they are 100% rated, yet too big for the pocket wheel.
Since I first posted this, I have designed a sliding hook that I can use with another type of chain fitting, but the system will oscillate back and forth instead of continuously run in one direction as they do now.
Unfortunately, this adds about $23,000 to the cost.

RE: Connecting Link; 3/8" Chain

1. It seems that this is not an overhead lifting application
2. Have you made chain pull calcs - is this thing over-spec'ed
3. Can you upsize chain and reduce chain grade to reach an acceptable link strength

4. Can you get lower-rated links and load test

RE: Connecting Link; 3/8" Chain

Quote (DavidStecker)

This drive system is in many of their plants, so I'm trying to stay with what they have since they first came to me for replacement parts.

So, what do they use now for links?

RE: Connecting Link; 3/8" Chain

Quote (DavidStecker)

Based on what they have given me for weight, I calculated a pull of about 7,600#

Perhaps you should share your calculation.

In thread725-498176: Closed Loop of 3/8" Chain last September you provided a link to this video, showing the pull chain at 3:52.

Rolling resistance: https://www.engineeringtoolbox.com/rolling-frictio...

Fr = c W


Fr = rolling resistance or rolling friction (N, lbf)

c = rolling resistance coefficient - dimensionless (coefficient of rolling friction - CRF)

I see two chains and eight wheels, or one chain pulling four wheels.

7,600/4 = 1,900 pounds pull per wheel.

Let's just for fun imagine that c=1.

That would mean that each wheel is supporting 1,900 pounds. 1,900 * 8 = 15,000 pounds.

Does that pallet weigh 15,000 pounds? I don't think so, but it might.

But, look at the typical values for c.

The largest c in the table is 0.4, and that's for car tires on loose sand. Hardly your case.

All the other values are much much less. I don't see a great match for the wheel/tire in the video, so let's see what happens with "truck tire on asphalt" c=0.01.

Does a pallet weigh 1,500,000? No way!

Let's guess that a pallet weighs 50,000 pounds. I think that's pretty conservative. With c=0.01 and two chains, that's a pull force needed of 500 pounds.

Are they pulling 15 pallets at once?

It just doesn't seem possible that 7,600 pounds of pull is needed.

RE: Connecting Link; 3/8" Chain

DVD and MintJulep,,
I have two of these projects going right now, the first actually measured the starting, (750#) and running pulls (350#) with a scale.
The other is based on an estimated weight of the modules.
The calculation I use is for moving railroad cars which has other derating variables to account for rail bed and temperature.
The second project has 18 modules, the estimated weight I was given is between 40,000 to 56,000 per module.
I compared the actual to the calculated and I'm think that I'm right on the money for the loads.
6,600# to 7,650#
The machine is capable of generating 36,000# at start up.
As I mentioned before, currently I'm stuck with the pocket wheel at this time.
How the customer is currently making the connection I do not have the detailed process, but I'm assuming they are welding.
As the manufacture, I can't leave it up to them.
Again, thank you for your input.
Best regards, David

RE: Connecting Link; 3/8" Chain

Have you considered replacing the pocket wheel with one that accepts 3/4 stud link chain so you can use an off the shelf Kenter link?

RE: Connecting Link; 3/8" Chain

Tugboat, yes, I've looked at Stud link, roller, Pewag, and standard conveyor.
We manufacture windlass' and I do have a 3/4" chain wildcat casting pattern, so that would be easy to provide.
As I mentioned earlier, I'm trying to stick with what they are currently using since they have over 46 factories.
Some need replacement parts and some need complete, new systems, so I'm hoping to keep them all uniform if possible.
Being in the marine industry yourself, I'm sure you know how hard it is to get people to change their ways.
One of my biggest pet peeves is the round mooring for U-bolts.
They are about the weakest shape you can make, yet I can't get designers to realize that.
Oval or pear shape would be way more bang for the buck.
Great hearing from you.
Best regards, David


RE: Connecting Link; 3/8" Chain

I think that I'm getting closer to finding what I want.
I just need to see what sizes they offer.
My browser isn't getting through to the link's I've found at Google.


RE: Connecting Link; 3/8" Chain

3DDave, Thank you the information.
Our firewall is blocking your link because it goes to Germany.
This government oversite of our system is a real pain.
I'll need to get the mechanical data for the chain material, but I think I could machine and EDM a link like this.
I think I could replace the cam pin with a hydraulic rated tapered pipe plug to cause the spreading force.
The ASTM and MIL standards I have only list performance requirements of the chain, no tensile or yield.

RE: Connecting Link; 3/8" Chain

It looks to me that your links have the wrong aspect ratio to use this method.

RE: Connecting Link; 3/8" Chain

3DDave, are you referring to the Connecting method or the Manufacturing method?
My first thoughts are to water jet the basic shape, radius the ID, and drill and tap for a tapered pipe plug.
Next, maybe heat treatment, then wire EDM.
Might switch those two, I need to get a better idea of what the kerf cut would be.
Please share your thoughts, I'm working off of first impressions until I know better.

Best regards, David

RE: Connecting Link; 3/8" Chain

You don't have room for the features you need. Make a drawing for yourself.

RE: Connecting Link; 3/8" Chain

3DDave, I'm still working on steel types right now.
I've been running the numbers for the ends of the chain link and I'm getting some huge yield requirements.
It's no wonder why the chain makers are so secretive about their alloy's.
Best regards, David

RE: Connecting Link; 3/8" Chain

Quote (DavidStecker)

I'm getting some huge yield requirements

That's pretty much expected given the geometry.

RE: Connecting Link; 3/8" Chain

I wanted to say Thank you to everyone that responded to this thread.
I have 2 other options for this project now so I'm going to move on until this comes up again.
Best regards, David

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