Removing Roll Pins

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I just had to replace the spring on a trailer jack. This is the spring that snaps the lock lever into the hole on the frame to lock the jack in place, either down for jacking, or up for hauling. I thought this would be simple. I had an old drum brake spring that was almost the same size, so all I had to do was remove the roll pin, replace the spring and put the roll pin back.
WRONG..... This turned out to be a nightmare of a job. The roll pin would not come out. I'm sure it was rusty, so I soaked it with PB Blaster. I hammered on it with a punch, and it got a flat end, meaning it would not pass thru the hole. But I figured I'd hammer it loose and then remove it from the other side. Instead, it broke off. I went to the other side and broke that side too. I took my grinder and flattened the end of the pin to remove the spring and the whole thing from the jack. I placed the part in my vice and hammered for a half hour, and it would not budge. Now this is just a 1/8" roll pin, nothing large, so common sense says it should have come out by hammering.
I placed the part in my drill press and decided to drill it out. I applied PB Blaster as a cutting oil and began drilling. The bit penetrated less than 1/32 of an inch before the drill bit just turned red and shattered. What ever metal those roll pins are made of, is extremely hard. I got another bit, and a minute later the tip of the bit was flat, and I had only gone in another 1/32 of an inch. Teo more bits and I was a little more than halfway thru the 1/2" thick piece of steel. I found a slightly larger bit, and one that was a top quality bit. That one threw sparks, but kept biting in, very slowly.
90% of the way thru the 1/2" shaft, that bit broke. I did not have any more bits that would fit. I finally took the broken piece of the bit and applied as much pressure on the drill press handle as I could. About the time the bit was glowing red, it broke thru. Total time spent drilling - almost 3 hours. Total time on entire job, 4 hours 20 min. Plus $10 to $15 worth of drill bits. (Next time I'll replace the jack).
How in the hell are roll pins supposed to be removed? No matter what you do, they are going to flatten on the end, and of course then they dont come out. I'm sure my rusty one did not help, but still, it should have come out easier than it did.
The rest of the job was easy. I installed the new spring, and replaced the roll pin with a cotter pin rather than another roll pin. Cotter pins come out much easier and can be drilled out with any bit if needed. If I never see another roll pin, it will be a good thing.
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Any chance the roll pin was bent? They are spring steel. Hard and tough, as you know:)
Al
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Big Al wrote:
<snip>

There are roll pin punches designed for this purpose. Like Al says, roll pins -- especially the higher-quality types -- are hard and tough. Like spring steel, almost (high carbon steel, methinks). If the roll pin is rusted, seized, or otherwise immobilized, even a roll pin punch might not work.
Look for another thread on alt.home.repair with the subject "Extracting broken bolt / screw" in which I ramble on about how to remove a broken bolt with an oxy-acetylene cutting torch, even if you don't know how to weld. You could apply the same technique to frozen roll pins.
The roll pin punch is basically the same as a pin punch or drift, but with a rounded convex "bump" to help keep the punch more or less centered in the roll pin. Below is a crude "usenet art" diagram of the punching end, not the hammering end (to the right of the diagram), of a roll pin punch. Visualize the solid punching end of a pin punch:
-------- | ) <-- bump keeps punch centered | --------
The above attempt is not to scale. On the roll pin punches that I own, the bump takes up most of the punch's business end, leaving only a thin margin which contacts the roll pin. They work pretty well, generally, but they won't work in every situation.
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I used to fix a machine that used roll pins that customer abuse could break but worse bend:(:(
often I replaced assemblies cause the pin couldnt be removed. frankly i have hated roll pins ever since.
they rate right up there with allen screws some jerk tightens till the wrench goes click click cl;ick:(
If you have something that uses roll pins its a good idea to give it a shot of oil on a regular basis
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Thanks! I've wondered for YEARS what the heck some "donated" tools I picked up were for!
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Describe the pin. Is it a roll pin or a split pin?
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On Sun, 30 Dec 2007 22:57:11 -0500, snipped-for-privacy@mucks.net wrote:

What's a split pin? I looked up "roll pin" on google, went to images. It's a roll pin !!!!
Repeat: What's a split pin?
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snipped-for-privacy@unlisted.com wrote:

AKA cotter pin. http://en.wikipedia.org/wiki/Cotter_pin
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wrote:

kinds, I am aware of two distinctly different types of "roll pins". The most common type is made of relatively heavy spring steel formed in a partial circle with a lengthwise slot. The other one is made of several turns of relatively thin spring steel without any slot, kinda like a short wide clock spring wound up real tight. The first squeezes the slot narrower when compressed and the second rolls the layers around themselves.
Don Young
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wrote:

Oh, a cotter pin. Why didn't he just say that? That's what I used to replace the roll pin, and it worked just as well for this situation. Cotter pins are not as hard to remove and if they need to be drilled out, they are a soft metal.
The roll pin I dealt with was the first one you said. The one with the lengthwise split in the side. And I sure found out how hard that steel is, by destroying 4 drill bits. I still cant believe that I was able to finish the job with a broken off bit with no tip on it. By that time I was so fed up with the whole job, I just burned it thru the last 1/16 inch or so. The remaining piece of the bit was glowing red when I finished.
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snipped-for-privacy@unlisted.com wrote: ...

There was a reason for using a roll pin in the original -- probably specifically for that hardness. Substituting a cotter is likely not a good idea.
--
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The drills break because of the split in the pin catching the bit and torquing it. Backing-up (as suggested) is a good idea. We used a "bucking bar", a slotted long heavy bar on the opposite side to increase the blow of the hammer. The key is a helper: one backs-up (or holds unit in a vise); and one strikes the blow (and it needs to be a good one!)
There are also tapered pins that have to be broached (if used in a new application) to taper both shaft and arm.
Many, many years ago I worked on mechanical NCR cash registers.
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dpb wrote:

require a roll pin, tapered pin, or splined pin (hardness optional) because the pin must be flush i.e. no part of the pin may project beyond the hole it is in. If that didn't matter, then perhaps a Cotter pin could substitute for a roll pin.
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maxodyne wrote:

Far more likely problem would be the shear strength.
--
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dpb wrote:

shear forces are handled elsewhere. As in an old automotive non-driven wheel bearing application: the wheel bearings support the axle weight (major shear force), an axle nut keeps the bearings in adjustment (minor compressive force), and the Cotter pin merely serves to keep the nut from moving (minimal compressive force).
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maxodyne wrote:

Doh... :(
The point is the OP replaced an original rolled pin w/ a cotter key. There's a reason there was a pin as opposed to a cotter initially. The likelihood is that it was for the shear strength w/ a somewhat lesser chance it was to minimize play.
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a bunch of folks wrote:

You're right. I went back & looked at the OP story and there it was, all about the trailer jack. Not too sure what that is, but I was visualizing a spring loaded pawl, pivoting upon and secured by a hardened roll pin. I could have my visualization wrong, though. Then I got so caught up in the roll pin removal adventure that I lost track of what the darn roll pin was was supposed to be doing in the first place :-P
Agreed, if a hardened roll pin is securing something to something else, best to evaluate the situation and ask oneself if a mild steel Cotter pin would suffice or would fail. Case in point for failure would be the common application of a roll pin to secure an automotive engine oil pump's externally splined shaft to its mating internally splined drive gear. Hardened steel shaft, hardened steel gear... even though a Cotter pin might fit clearance-wise, it would eventually fail, and with catastrophic results.
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wrote:

Since when has anybody called a cotter pin a split pin?
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snipped-for-privacy@mucks.net wrote:

I've heard them called that. I think it's a regional thing... Like creek or stream? river or bayou? What I would call a creek, my relatives in North Carolina call a branch. Or "brainche", as they pronounce it. "Cotter" sounds like someone's last name to me. If so, then Cotter's "pin" resembled a pin that had been "split". Dunno.
All Kleenexes are tissues, but not all tissues are Kleenexes. More or less.
Perhaps the real answer is lost to antiquity. Anyone know the origin of the "Cotter" pin?
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On Mon, 31 Dec 2007 15:38:28 -0600, snipped-for-privacy@unlisted.com wrote:

Depending on the semantics........
All these pins are spring pins. There are two types made.
A slotted spring pin commonly called a split pin or roll pin http://www.rollpin.com/ProductInformation/Springpins/Rolled/index.html
A coiled spring pin commonly called a roll pin http://www.rollpin.com/ProductInformation/Springpins/Coiled/index.html
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