Chain breaker and spinner

[Franny K]

I am 'frugal', but not reckless......

Here are some photos from my experience:

View attachment 623310

,.,.
Philbert

Looks like you are 1 for 6 on pressing out a salvageable rivet. When you get two on a tie strap try it, I think some of the other pictures are misleading as to what results are possible.

I am not recommending doing so but the part in shear stress while in use does not seem to me to have been distorted much if any.

If the punch is real close in size to the hole in the tie strap, probably not going to work.

 

[Philbert]

Looks like you are 1 for 6 on pressing out a salvageable rivet. . . .I am not recommending doing so but the part in shear stress while in use does not seem to me to have been distorted much if any. If the punch is real close in size to the hole in the tie strap, probably not going to work.

The 'crown' /spun head end of the rivet is somewhat malleable, but cracks if worked too much, and usually breaks off. The part of the rivet that passes through the tie strap also tends to bulge a bit, which makes it harder to re-insert (larger diameter). That said, a lot of presets have been reused through the years, so people find ways to make them fit. As you suggest, the manner of removal may affect how much the rivet is deformed.

The Granberg Break-N-Mend tool suggests, this and the instructions claim that it reforms the rivets; I was never able to do this while experimenting with this tool.

Also, as you state, much (most?) of the shear strength of the rivet may be retained, but most of the lateral retention of the tie strap is lost, without a spun or peened crown.

Philbert

 

[Wood Doctor]

I have to agree with Philbert on this "saving removed rivets" issue. The tops of these rivets after pressing them out have been subjected to enormous stress. Pressing that material back down, whatever is left, is hazardous. There really is no way of knowing if enough remains there or what condition that it is in. Even if you examine the rivet head after spinning a new one, that head could be very weak internally. It's a gamble to say the least.

 

[PDXchain]

I am 'frugal', but not reckless.

There are a lot of things that people 'do', or 'have always done', 'get away with', etc., that are 'not a good idea'.
The chain manufacturers do not advise this; might hold, but definitely creating a 'weak link'.

Here are some photos from my experience:

View attachment 623310

These are presets and rivets after removal with a purpose-designed press / 'breaker'. Notice how deformed the rivets' ends are. There will be even less material left if the user files / grinds off the ends before punching them out (note that I may salvage and reuse tie straps, if they are are in good condition and not deformed in the removal process - the drive link serves as a press 'die' for this).

Here are a few chains I acquired, and what I found once cleaned up a bit:
View attachment 623313

Aside from being upside down (many are also inside-out) , note how this tie strap is essentially held by friction, rather than being spun / peened-over to form a mechanical crown.

View attachment 623317
(Yes; that IS a Pop-Rivet!)

View attachment 623319

How many different chain brands, and pitches can you spot? Can you spot the re-used preset?

Philbert

Haha...you have most of the saw chain manufacturers represented there

 

[Philbert]

Haha...you have most of the saw chain manufacturers represented there

Yes. All on one loop!

Philbert

 

[Philbert]

* FYI - This is something that I posted somewhere else, in a related discussion, but makes sense to add it here.

More About Rivets

At the most basic level, 'mushrooming' the ends of rivets holds a saw chain together, regardless of whether the rivets are peened, or spun, or fed a junk food diet. But rivets do much more!

While the ends ('hubs' in the illustration) are soft and malleable enough to be spun and formed, the center ('hub') is actually hardened and acts like a bearing in the drive link holes. This was demonstrated to me by an engineer conducting quality control tests on chain parts. Exactly how they they get different hardness levels on these tiny parts is magic to me, but I am easily amazed.



'Properly' spinning the rivets not only creates the mushroomed ends, but also expands the diameter of the rivet hubs so that they tightly fill the holes in the tie straps. This way, all of the pivoting movement occurs at the bearing, lubricated by the bar oil. If movement occurs where the softer hubs of the rivets meet the tie straps, this will contribute to excessive wear, and 'chain stretch'.



*BTW - a 'preset' is just a tie strap with the rivets already attached, used on one side of the chain, which makes assembly a lot easier than trying to manipulate tiny rivets. I do not know of any manufacturer than normally sells chain rivets that are not part of a preset.

So, while reusing a rivet, or smashing it with the flat end of an axe, may hold a chain together, it is like driving around on bald tires, or standing on a rickety ladder: it works, until it doesn't. But it is not a 'best practice'.

Philbert

 

[heimannm]

I have an old Oregon hand tool that is a combination breaker and hammer for peeing the rivets and includes a "die" used to resize the rivets that you just punched out. I will try to remember to add photos when I'm at the computer again.

Mark

 

[Franny K]

While the ends ('hubs' in the illustration) are soft and malleable enough to be spun and formed, the center ('hub') is actually hardened and acts like a bearing in the drive link holes. This was demonstrated to me by an engineer conducting quality control tests on chain parts. Exactly how they they get different hardness levels on these tiny parts is magic to me, but I am easily amazed.

My guess would be they have some sort of device that makes electricity move back and forth inside the rivet part they want hardened to the point it gets hot. Perhaps chill bars for the ends. Induction hardening.

Maybe the center part is forged bigger from wire the diameter of the ends.
interesting topic

So, while reusing a rivet, or smashing it with the flat end of an axe, may hold a chain together, it is like driving around on bald tires, or standing on a rickety ladder: it works, until it doesn't. But it is not a 'best practice'.

I don't like your analogy. More like setting floor joists or rafters with lumber with no grading stamp and helpers that seem to have their personal lives on their mind more than what you told them.



On this forum lately there has been question would this tie strap package on ebay shipped directly from China be what I need. Sure using new parts from the chain manufacturer is the best but which is really better re using pressed out pieces never put in service from the exact chain or unbranded stuff that claims to fit a whole assortment of brands?

 

[Philbert]

I have an old Oregon hand tool that is a combination breaker and hammer for peeing the rivets and includes a "die" used to resize the rivets that you just punched out.

The Granberg 'Beak-N-Mend' (ViseGrip-style chain tool) also has a die to 'reform' used rivets for reuse. I have had limited success with this, but it still does not replace material that was lost from filing / grinding / punching.

https://www.granberg.com/product/g605c-break-n-mendbreaks-rivets-chain/?v=7516fd43adaa
Philbert

 

[Philbert]

My guess would be they have some sort of device that makes electricity move back and forth inside the rivet . . . . Induction hardening.

Probably. Or maybe something in the forming process. Metallurgy can be part science, part art, part magic. However they accomplish this, I found it interesting that it is a carefully engineered part, and not just a 'dumb, old, flattened nail'. Also provides some perspective on the design, engineering, and quality control processes involved in chains, and, perhaps, some insight on the differences between 'top tier' and cheaper chains.

I don't like your analogy. More like setting floor joists or rafters with lumber with no grading stamp and helpers that seem to have their personal lives on their mind more than what you told them.

My point is that there are differences between 'good enough' and OEM specs. Some people don't care until they have a problem, like a chain breaking, or excessive chain stretch. Other guys on this site are interested in optimizing performance. This points out one of the differences between spun and hammered chain rivets.

On this forum lately there has been question would this tie strap package on ebay shipped directly from China be what I need. Sure using new parts from the chain manufacturer is the best but which is really better re using pressed out pieces never put in service from the exact chain or unbranded stuff that claims to fit a whole assortment of brands?

Tie straps / rivets vary in several dimensions (please see illustration above):
- hub diameter
- flange bearing diameter
- flange bearing width
- rivet center spacing (even for the same pitch chain).

While many aftermarket companies copy Oregon chains, there are differences between drive links that are straight gauge or swaged, narrow kerf chains, etc. Some Oregon style presets will physically fit some STIHL chains, some will not. I have some different Oregon 1/2" pitch presets that will not fit other Oregon 1/2" pitch chains. I have tried to 'test fit' some presets and tie straps from different manufacturers that appeared identical, but were off by several thousandths of an inch when paired. Like using the wrong size or thread bolt for a task.

This is, of course, separate from the consideration of quality. Some guys are happy with the cheaper, third party chains due to lower cost, or cheap, clone replacement parts for their saws. I feel more comfortable using the OEM stuff when available.

As far as reuse, regardless of whether or not the chain has been put in service, you still have the issues of lost metal from grinding (a popular method among several members on this site) or punching (small ring of material typically removed), as well as metal fatigue from being worked several times. So, your binary choice leaves out the best option: identify the presets needed for the chains you run (or repair) and keep a small supply of them before they are needed, so that you have the right thing when needed.

Philbert

 

[Franny K]

The folks posting on here seem to mostly use full size 3/8 maybe that size is interchangeable in dimension for the splice parts.
13rm and 25ap in the 1/4 pitch do not interchange
the 3/8lp or picco do not interchange Stihl vs Oregon in either the 0.043 or 0.050.
I threw away one Woodland pro .325 chain because it did not match what I had don't recall if it was NK or not. By the time it needed a link removed the compressed and stretched length was different by a significant amount.