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JoeLee
06-17-2019, 10:34 PM
I would like to have a small cylindrical square. I don't want to spend a fortune on a used beat up one and I don't need one that is 12" tall either.
The perfect size for my needs would be about 3" to 4" in length x what ever the OD would be. 1 1/2" or so.
I know that they hold pretty close tolerances on them, in tenths or better, consistent through out the length and their polished, usually.
I don't want one with an oil hole, or holes drilled through it. I've seen them both with or with out.
Don't really care how square the end is as that's part of the project, squaring an end it up.

I've looked through several parts suppliers and none of them list these by size. Only engine make model etc. Understandable.
So...... Any one have any idea where I might find a pin in the approx. size I'm looking for?

JL....................

paul463
06-17-2019, 11:12 PM
Junk pile at a heavy duty diesel shop.

JoeLee
06-17-2019, 11:15 PM
Junk pile at a heavy duty diesel shop.

Don't want anything that's worn or scored.
JL...

paul463
06-17-2019, 11:18 PM
Don't want anything that's worn or scored.
JL...

Look around. Wrist pins really don't see much wear and there are lots of them in each engine, you should be able to find one that is near perfect.

Willy
06-18-2019, 12:11 AM
Like Paul said, truck shop or equipment repair shop, ag equipment, etc.

Pistons are expendables on a rebuild and they come with new pins even though the old ones have no measurable wear.
As an aside I have a bunch here from a 4 cyl. 528 Cat skidder and some from N14 Cummins engines. I forget the dimensions at the moment but even the small Cat ones are probably a little larger than what you're looking for. The N14 Cummins pins are about 5+ inches long and have a diameter of 2.5 inches.

Bring a box of donuts and you'll probably go home with a box full of different size pins.:)

gambler
06-18-2019, 01:44 AM
seriously, donuts work

JoeLee
06-18-2019, 08:23 AM
Like Paul said, truck shop or equipment repair shop, ag equipment, etc.

Pistons are expendables on a rebuild and they come with new pins even though the old ones have no measurable wear.
As an aside I have a bunch here from a 4 cyl. 528 Cat skidder and some from N14 Cummins engines. I forget the dimensions at the moment but even the small Cat ones are probably a little larger than what you're looking for. The N14 Cummins pins are about 5+ inches long and have a diameter of 2.5 inches.

Bring a box of donuts and you'll probably go home with a box full of different size pins.:)That would be perfect. I'de buy a new one. Hopefully that model doesn't have oil holes drilled through it.

I found a picture of one, no oil holes, good wall thickness and the price is less than $50.

Now that I know what to look for I may be able to hunt one down locally. Just didn't know what make or model to look for. It's basically a big dowel pin with nicer finished ends.


TNX......

JL.............

wdtom44
06-18-2019, 08:38 AM
If there is a good parts guy at a supplier near you and you get him at a time when he isn't too busy he would probably know what you are looking for off the top of his head.

Willy
06-18-2019, 09:41 AM
Joe any of the 12-16 liter truck engines will have similar dimensions of the N14 (855 cu. in.) Cummins pin I mentioned. Caterpillar 3406 would also be popular as would Detriot Diesel 60 series pins. The newer DD13-16 series and Cummins ISX 15 are also very popular and would be of the same size range. Not sure if imperial dimensions are required or if metric is suitable, probably not an issue but the older Cummins and Cat designs are imperial.

Look around though as you should be able to get them for a lot less than 50 bucks a pop new.
Looking at some of the pins I have this morning and I cans that it has been used but I cannot measure or feel any wear.

JoeLee
06-18-2019, 10:15 AM
If there is a good parts guy at a supplier near you and you get him at a time when he isn't too busy he would probably know what you are looking for off the top of his head.I found a couple guys local here that do diesel repairs. They have lots of used ones. I'm going to go have a look and see what kind of shape their in.
As long as they aren't outside rusting away or heavily scored up.

JL...............

JoeLee
06-18-2019, 10:17 AM
Joe any of the 12-16 liter truck engines will have similar dimensions of the N14 (855 cu. in.) Cummins pin I mentioned. Caterpillar 3406 would also be popular as would Detriot Diesel 60 series pins. The newer DD13-16 series and Cummins ISX 15 are also very popular and would be of the same size range. Not sure if imperial dimensions are required or if metric is suitable, probably not an issue but the older Cummins and Cat designs are imperial.

Look around though as you should be able to get them for a lot less than 50 bucks a pop new.
Looking at some of the pins I have this morning and I cans that it has been used but I cannot measure or feel any wear.


Dimensions aren't important as far as metric or imperial goes. Just the rough size of around 4 -5" in length x 2" or 2 1/2" on the dia. would be just fine.
Worst case is if I can't find an good used one I now have makes and models of engines to use to source out a new one.


TNX......... JL

JoeLee
06-18-2019, 10:20 AM
Now I wish I had a the pins for these pistons. I posted this picture several years ago on this forum, my piston collection.

JL................

http://i911.photobucket.com/albums/ac317/JoeLee09/My%20Plug%20Cutter/My%20Pistons/Image001.jpg

Willy
06-18-2019, 10:49 AM
Now I wish I had a the pins for these pistons. I posted this picture several years ago on this forum, my piston collection.

JL................



Holy smokes Joe, you been fixin' weed whackers again!

Don forget the donuts. It's amazing how many doors you can open up with a box of donuts.:)
Who knows you may find some other useful goodies.

Dan Dubeau
06-18-2019, 11:23 AM
Those are some pretty uncomfortable looking shop stools. :)

boslab
06-18-2019, 04:27 PM
We had a ship in the deepwater harbour in work delivering iron ore from South America, they had a problem with a cylinder and did a swap at sea, the piston was gigantic, ended up on the wharf for several years before being scrapped. Too big for the trunk of my car, I tried couldn’t close the lid
Cat d8 wrist pin is what I have, they have a charming name over here, gudgeon pin, funny name
Mark

Tim Clarke
06-18-2019, 04:35 PM
Joe, I'm really interested to know how you machine/lap/grind/whatever, the end(s) to make square. I have some from a 3306 Cat engine hiding somewhere in my collection of "goodies" I checked them years ago when I brought them home and even my old Stanley combination square, after maybe 60 years, is closer to square. These have holes thru the center, which should be better for gauge duty I've heard.

If your search proves unsucessful, Maybe I can help you out. Providing I can find them!

true temper
06-18-2019, 06:03 PM
A couple of my wrist pins that I found in the junk. Not sure what they are out of some kind of natural gas compressor engine. https://uploads.tapatalk-cdn.com/20190618/db4cfdc85f69f3741c9f5c2880b2fe64.jpg


Sent from my iPhone using Tapatalk

JoeLee
06-18-2019, 10:01 PM
Joe, I'm really interested to know how you machine/lap/grind/whatever, the end(s) to make square. I have some from a 3306 Cat engine hiding somewhere in my collection of "goodies" I checked them years ago when I brought them home and even my old Stanley combination square, after maybe 60 years, is closer to square. These have holes thru the center, which should be better for gauge duty I've heard.

If your search proves unsucessful, Maybe I can help you out. Providing I can find them!Tim, there are a couple ways to go about it. One would be to set it up on a v-block and grind the end on the surface grinder, or chuck it up in the T&C grinder and face the end. I have a 12" master square that I would be using to check it. Depends on how square the end is to start. This is why I'm not real keen on the idea of a use one, unless it's well preserved. If some one hammered the end to drive it out of the piston then that's more work for me.
The other thing is I have this vision of people having piles of these sitting outside in a pile behind their shop. For $30 or $40 buck I would be further ahead to buy a new one.
We'll what I come up with first.

JL...............

754
06-18-2019, 10:45 PM
Posting your location can help you a lot.
I have seen very nice shiny diesel pins that were 6 or 10 thou under in the middle..

BCRider
06-19-2019, 12:43 AM
Joe, I was looking at the three pistons in your picture of your piston collection. It took me a few seconds to realize that I was looking at the bandsaw in the background. Then I just about spewed my nice after dinner bourbon over my monitor. Dem's some serious big pistons ! ! ! ! And yeah, toss a bit of a cushion on top and a set of casters and they would be amazing shop stools ! ! ! !


I'm a bit curious about why the distaste for oil holes. If the pin you get has oil holes they don't cover much of the surface and would be easily avoided. So I really don't see what the big deal would be if the pins were right in every other way.

Willy
06-19-2019, 01:56 AM
Most industrial duty diesel engines do not require an oil hole in the connecting rod small end or an oil hole in the pin .
Like the set of rods shown below from a design that dates back to the early 50's, a 6 cyl. 855 cu. in Cummins. The bushing in the rod for the pin was pressure lubed through a channel in the rod from oil bled off of the con-rod bearing.
Those are 2.5" pin bores just give some perspective to the illustration.


https://i.imgur.com/ez2OnTU.jpg

Doc Nickel
06-19-2019, 03:24 AM
Has anyone thought about just looking for a new one, like off eBay? There's a bunch listed under "piston pin", "wrist pin", "large piston pin", "diesel piston pin" and so forth.

Average price is less than $20, often with free shipping. The largest two I can find don't show any dimensions, but from the look of the boxes are in the ballpark of 1.5"-2" in OD, and 3-5" long.

Doc.

JoeLee
06-19-2019, 07:54 AM
Joe, I was looking at the three pistons in your picture of your piston collection. It took me a few seconds to realize that I was looking at the bandsaw in the background. Then I just about spewed my nice after dinner bourbon over my monitor. Dem's some serious big pistons ! ! ! ! And yeah, toss a bit of a cushion on top and a set of casters and they would be amazing shop stools ! ! ! !


I'm a bit curious about why the distaste for oil holes. If the pin you get has oil holes they don't cover much of the surface and would be easily avoided. So I really don't see what the big deal would be if the pins were right in every other way.Just personal preference I guess. Since they come both ways, I would rather have one without holes.
On the other hand, one with a hole could possible serve as a way to mount a dial. Just thinking. Perhaps slide a rod through it etc.

JL............

JoeLee
06-19-2019, 08:01 AM
Has anyone thought about just looking for a new one, like off eBay? There's a bunch listed under "piston pin", "wrist pin", "large piston pin", "diesel piston pin" and so forth.

Average price is less than $20, often with free shipping. The largest two I can find don't show any dimensions, but from the look of the boxes are in the ballpark of 1.5"-2" in OD, and 3-5" long.

Doc.Yea, I have. Mentioned it a couple times in previous posts. First I'll see what I come up with for used. If I can't find a nice clean one new is my second option.

Getting it square off an end will be the next chore. Don't know how square the ends are but I'm betting they aren't perfect. I have a few methods in mind.
Perhaps someone could offer some ideas.

I don't see what the big expense is in buying an actual cylindrical square. I'm sure they are all centerless ground just like the wrist pins. Outside finish has got to be about the same as wrist pins, in fact wrist pins may be polished to a higher degree. Centerless grinding is the fast and easy operation, squaring an end to .0001 or so is where the work is.
I guess they price is high because of what it is..... a precision tool.

JL..............

J Tiers
06-19-2019, 10:00 AM
......

I don't see what the big expense is in buying an actual cylindrical square. I'm sure they are all centerless ground just like the wrist pins. Outside finish has got to be about the same as wrist pins, in fact wrist pins may be polished to a higher degree. Centerless grinding is the fast and easy operation, squaring an end to .0001 or so is where the work is.
I guess they price is high because of what it is..... a precision tool.

JL..............

There is rather a large difference (although one might not realize it) between a piece that actually happens to be square, vs a piece that is intended to be square, was made to be that, and is known by testing to be square etc within a certain tolerance, having a paper trail to a known standard.

Not all of that higher price is a "because we can" charge.

JoeLee
06-19-2019, 10:33 AM
There is rather a large difference (although one might not realize it) between a piece that actually happens to be square, vs a piece that is intended to be square, was made to be that, and is known by testing to be square etc within a certain tolerance, having a paper trail to a known standard.

Not all of that higher price is a "because we can" charge.Good points. Since the ends of a wrist pin are an insignificant surface I can understand the mfg. not fussing with them.
Interesting to see just how close one might be. I'm sure they all vary.

JL..............

754
06-19-2019, 10:47 AM
In manufacturing squares, the difference between grades, is often a reflection of the amount of finishing to get it to spec.
I have read that most Starrett squares are the same, the higher grades just have more hand finishing involved.
Something about a dark room with a small light on one side, and checking against a master square.

BCRider
06-19-2019, 11:49 AM
There's some testing you'll want to do to check the WP to determine if it will serve you as a cylinder square. I went through them when I made my own cylinder square last Fall or whatever it was. Basically anything reasonable can be used as a cylinder square if it passes the tests. And alternately with good measurement tools and techniques we can tune up a cylinder square to some extent.

First off measure the diameter along the length and at at around about 5 "clock points" mark the points you measure at the ends so you keep the radial lines for these consistent along the length of the pin. Repeat these five or so radial measurements at about 6 to 8 positions along the length. You're looking to see if there's any "egg shape" or multiple lobes that might be present... or rather there will be but you're looking to see just how bad it is and if it's close enough for your needs. Or at least to know what you've got. Keeping in mind that if you know what you have then you can account for it when using it.

Next and if it passes the diameter measuring set it on a couple of good V blocks (should be a matched set) and run a DTI on a stand along the length to check for any curvature of the axis. I'd repeat these along the same axes you did with the diameter measuring.

Finally make up a table of the readings and length variations which would allow you to do up a map of the pin diameter and straightness.

For all this you'll be wanting to use a mic that has a 10's vernier and at least a DTI which has .0005 graduations. And generally you an resolve both of these to within .0002 without too much eye strain.

I did find that when doing this that it took a bit of focus and repeating measurements because there's a feel to it before you know you're getting consistent readings. So figure on repeating a lot of the early measurements after the first time through to double check your technique. It doesn't take a whole lot of sloppiness to mess things up when we're looking at resolving down to plus or minus a tenth of a thou. Or a hundredth of a millimeter.

Do a "map" of the pin using the measurements. If the diameters are "eggy" or "lobe'y" with two or more fat places around the diameters then it might still be useable provided the end to end checks done in the V blocks indicate that it's straight even if it has a lobe or three and is not truly round. But that's why you're measuring it to find all this out. And you need to map any and all features first before you can start to think about squaring up the end.

Bented
06-19-2019, 09:35 PM
Ask yourself this question. What are wrist pins made for?
The working surface of a wrist pin is often ground to a high degree of accuracy on the OD. This is the surface that does the work.
The ends do no work short of holding them in place, grinding the ends as if making a tool would not improve its function. Many are simply turned before hardening and finish grinding of the OD.

Roll the dice.

Joel
06-19-2019, 09:48 PM
...grinding the ends as if making a tool would not improve its function.
Unless they are full floating pins, in which case the ends will be ground to a very tight tolerance for squareness (and length - else they pound the locks out). I have no idea how common full floating pins are in the large diesel engines being discussed. Such pins also do not get pressed in or out, so a used one might still be in pretty fair shape.

JoeLee
06-19-2019, 09:52 PM
Ask yourself this question. What are wrist pins made for?
The working surface of a wrist pin is often ground to a high degree of accuracy on the OD. This is the surface that does the work.
The ends do no work short of holding them in place, grinding the ends as if making a tool would not improve its function. Many are simply turned before hardening and finish grinding of the OD.

Roll the dice.Yes, and this is why I want to try making the square out of a wrist pin. The only surface I'll have to work on will be the end that I'm going to call the bottom.

JL............

JoeLee
06-26-2019, 12:22 PM
I ended up getting a new diesel wrist pin.
It has a beautiful polished finish, I doubt that any cylindrical square that you could buy would have a better finish.

I checked the dia. of it in various places, top, middle and bottom end 90 deg. apart and I couldn't find any variations at all, if there is it's in the millionths.

https://i.postimg.cc/8fStHvjb/IMG-20190626-110334.jpg (https://postimg.cc/8fStHvjb)

I checked it for squareness using my Starrett master which is supposed to be good to .0001 in 6". I found two sides to be perfect, meaning no light can be seen between the blade and the cylinder. I marked the two sides so I know that they are the square sides.

https://i.postimg.cc/Wd3SXTbx/IMG-20190626-105951.jpg (https://postimg.cc/Wd3SXTbx)

I also checked it with my dial being used as a comparator, less than .0001 difference between the two sides indicated as square.

https://i.postimg.cc/7b3BLKWt/IMG-20190626-110227.jpg (https://postimg.cc/7b3BLKWt)

At this point I'm not sure if I should mess with the bottom of this or not.
I have seen several cylindrical squares where on the top they are marked like A,B,C,D probably to indicate the degree of squareness of the side.

JL...............

Willy
06-26-2019, 12:35 PM
Yes they do have a very nice finish right out of the box don't they and the ends do need to be square for the pin retainers. But yeah I too am always amazed at how these mass produced parts have such close tolerances in on that end of the pin.

What was the pin originally intended for? Was it an OEM part or an aftermarket item?

sasquatch
06-26-2019, 08:36 PM
Definetly a truck rebuild shop or dealer.

JoeLee
06-26-2019, 09:54 PM
Yes they do have a very nice finish right out of the box don't they and the ends do need to be square for the pin retainers. But yeah I too am always amazed at how these mass produced parts have such close tolerances in on that end of the pin.

What was the pin originally intended for? Was it an OEM part or an aftermarket item?That was the one you recommended. Cummings N14. This one is aftermarket.
5" x 2 1/2"

Would there be a bigger one??? or would we be getting into locomotive or ship diesels?

JL..............

Willy
06-26-2019, 10:34 PM
There are literally millions of 12-16 liter truck and industrial engines that would use a pin roughly the size of the one you have now and this of course makes availability and pricing reasonable.
Even a D-8 Cat uses the same basic 3406 series engine that I mentioned earlier and that Cat used to build as a truck engine (Caterpillar is no longer in the truck engine business). Once we get into the larger series of industrial engines procurement of parts becomes more of a serious hunt if looking for used and very pricey when looking for new.

I'm not saying they aren't available for a song if you know of some local large industrial engine rebuilders. But I think we both know that the number of rebuilds done to engines in that class may only number in the thousands nation wide compared to the millions in the heavy duty truck market. Also as a rule, when components get large and pricey they are very often checked for wear and reused if within service limits.

JoeLee
06-27-2019, 07:22 AM
Willy, I just thought you might have some makes and models of bigger diesels. But anything bigger than one I just bought would probably be in train or ship engines.
Not easy to find in parts stores as you said.

JL............

Willy
06-27-2019, 11:04 AM
Sorry Joe, I can't give you any viable alternatives, once you get into the the larger engines displacing 18-50 liters there are very limited choices. Very limited availability due to low production numbers and no aftermarket parts, OEM will be very expensive.

mikey553
06-27-2019, 11:47 AM
Joe, I am thinking about getting a wrist pin as well to use as a cylindrical square. I have found one off Ebay sold by "highway_and_heavy_parts" for $32.63 plus shipping. It appears to be exactly the same as yours. Did you get yours from this place?
Since you got good measurements from yours, I don't want to take chances with a different supplier.

JoeLee
06-27-2019, 01:20 PM
Joe, I am thinking about getting a wrist pin as well to use as a cylindrical square. I have found one off Ebay sold by "highway_and_heavy_parts" for $32.63 plus shipping. It appears to be exactly the same as yours. Did you get yours from this place?
Since you got good measurements from yours, I don't want to take chances with a different supplier.That's the place I got mine from. I bought it directly from them. It is aftermarket. I'm pretty happy with the accuracy and the finish. I think I'm just going to leave the bottom alone. I have the two sides that are perfectly square marked.

JL..............

Joel
06-27-2019, 02:36 PM
FWIW, here is one on Amazon for $30 plus $9 shipping:
https://www.amazon.com/NEW-CUMMINS-PISTON-4923748-4059363/dp/B078N82VN9/ref=sr_1_6?keywords=N14+Cummins+pin&qid=1561659920&s=gateway&sr=8-6

As this has come up before, I was going to suggest that you post the part #/alternatives (& source, price, dimensions, tolerance) so this thread could be referenced in the future. Looks like most has been covered.