Looking for Fairbanks hammer operating manual...

There are a few really good modern hammers out there, for sure, Sam. Probably, if a person has to do a serious rebuild on an old one, the total costs go by the cost of some of the modern hammers. I think, in the end, an old hammer put right and kept right is equal to, or nearly so, the really good modern hammers.

How's your little baby hammer treating you?

Mike
 
Sam, and your parents could have just adopted a kid instead of having you too, if what they wanted was the easiest way out.

I could just go buy shelf brackets, gate latches, hinges, etc., from China, instead of making my own, too. They may even work just as good or better than the ones I make.
 
Hey guys. I thought I would share a few new pictures.
Following is bushing installation setup.
pressingfromfrontlores.jpg
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Here it is from the back.
bushingpressinglores.jpg
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Here is the 3/4" drive socket I used to pull against.
pressingsocketlores.jpg
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Here are both bushings in place.
bushingsinlores.jpg
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Here are the new shaft and the reamer I used to clean the front bushing up a little after I pressed it in.
bushingsinlores.jpg
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I found a couple more to share.
Here is the motor checked out with new bearings, painted and ready to install.
motorpaintedlores.jpg
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Here are the 1/2" x 4" flat bars drilled for mounting holes tapped in the side of the base of the hammer to be used as the supports for the motor mount table.
motormountbracketslores.jpg
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I discovered while drilling the holes in the base/post of the hammer that the casting is hollow. It is about 1 1/4" thick in my 75# hammer. After drilling on both sides, I could see right through the base/post of the hammer. I drilled down around the back end of the top anvil strap. As I discovered earlier, the anvil itself is also hollow. I can't imagine how heavy these machines would be, if everything was solid.
 
I talked to the machine shop, and we decided I should use a die grinder with a 60 grip little flapper disk to hone out the back bushing where the shaft hit it when the shaft was inserted from the front. It took an hour or so of work to get the shaft all the way through. After I got it started, I then rotated the shaft in the bushing, so it would leave a witness mark, so I knew where it was rubbing. I then used the flapper disk on those spots. Inserted through both bushings, the shaft is quite tight with just a little play. The same is true when the shaft is just inserted in the front bushing. However, with the shaft just inserted in the rear bushing, there is more play than I would like. Thankfully, the play is above the shaft, so while the shaft is weighted by the flywheel and the drive pulley, the play should not be an issue.

If I did this again, I would make and install one of the bushings and install the shaft in that bushing and in the bushing hole without the bushing. I would then measure from the side of the shaft to the edge of the bushing casting hole in 8 or so spots around the shaft. I would then make that bushing with the error built into it and mark where it is offset, so it could be installed to correct any error in the bushing casting hole alignment.
 
Roger,

Since you got into this particuar goat screw, I've been wondering, unsuccessfully I'm pretty sure, how the factory got this done. Line bored, like you and the machine shop felt was likely, but how is the question I'm been mulling. Was the jig set up 90 deg. to the hammer slide in the casting? Was the line boring done and the hammer slide machined off of it? Or ???

I'm pretty sure there weren't any multi-head mill/drill machines around then... =] But I wonder if they had jig frames the casting was set into and a number of mill/drill processes happened sequentially. Maybe Bruce is going to know about this from his experiences in historical machinery.

Hopefully, the extra room in the rear bushing will only amount to a little extra space for grease/oil.

Mike
 
I talked to the machine shop again today. I decided to pull the rear bushing. After all of this work, I just didn't want any extra play in a bushing, even if it possibly would not be an issue. So, now the question is, how to correct it? The machine shop told me today that there is an outfit in town with a portable line boring machine. I suppose he didn't want to lose the job and tell me that earlier. He also said they may want $100/hour to go do the work offsite.

After thinking about it more, I decided to pull the rear bushing, put the shaft through the front bushing and out the rear bushing casting and measure in various points between the shaft and side of the casting, as I said I would do, if I was to do this again. Well, I'm doing it again. I did this in 8 places in the front of the rear casting hole and 8 in the back of the rear casting hole. I used a small steel ruler with divisions of 64ths. I tried everything else I had, and this was the best way.

There is about 3/64" difference top to bottom and 11:00 to 5:00 o'clock from the back of the rear bushing. The numbers from the front of the bushing were all within 1/64" of the back with one exception. It is more difficult to measure from the front, since the front yoke is in the way, so I would expect some variance in the numbers. I also just realized as I was writing this, that the back bushing is a tapered bushing, with the narrowest portion in the front. That explains the difference between my front readings and the ones from the back. The front may be narrower by about 2/64"diameter. I will talk the measurements over with the machine shop and decide what to do. I am hoping that the numbers show that the shaft is passing through the rear bushing level and not at an angle. If it is, a new bushing could be drilled with the center of the shaft hole offset to correct for the misalignment.

If this won't work, it will probably be new bushings and big bucks line boring. However, that raises Mike's question, which I had already contemplated. That is what do you line bore against as a reference? Nothing on the casting appears square or level. The only thing I can think of would be the flanges on the front and back yokes outside of the bushings. They appear to be the only machined surfaces on the hammer.

I also noticed while I was measuring things that the casting hole in the front yoke is probably 1/8" thicker outside the bushing one one place as compared to others. That is a bunch. Obviously, the casting holes were not centered in the yoke casting.
 
Robert,

I mentioned this before... When I talked with Sid at the start of our hammer rebuild, he mentioned an out-ness greater than 0.025" in the shaft/bushing was cause for rebushing. Not like you don't know this... 1/64" is 0.016". I don't remember if Sid gave me a number to rebuild to. but I'd guess it at 0.002" to 0.005" based on that being the tolerance of arm hole & pins.

Our machine has a milled surface for the half of the hammer guide that is part of the front of the casting. Yours isn't milled/ground?

Mike
 
Remeber guys, that in that era, tolerences that great were acceptable, even considered excellent.
The only milled surfaces I see on mine are at the faceplate mating up to the machine.
 
I hear what you guys are saying. There was more than .025" play in the rear bushing, if the shaft was inserted in it alone, after I honed it out at the spots that were rubbing to get the shaft through. Certainly, it would never be in that bushing alone, and the shaft was nicely tight when installed in both bushings. However, I don't want the potential for some odd wear thing happening and the shaft getting loose, and I just want this done right. It is quite possible that if I had hired someone to do this job, they would have reassembled the hammer with it this way and called it good.

I think that building the offset into the new bushing should work, if the shaft is passing through it parallel to its edges and not at an angle. That would be the low-tech solution, and line boring would be the high-tech solution. The hammer does have a machined face on the frame as the back ram guide. Inside of the front cover on the arms that stick out from the frame is a machined slot for the cover to rest on. I am not certain if either surface is accessible enough to reference for the line boring, but they would be ideal, since that is the plane that the shaft should be perpendicular to. However, the flanges on the yoke should be on that same flange, and they are accessible.
 
I'd tend to go with the "ram guide" in the casting, simply because of it's intimate relationship with the ram and the shaft. If you remember me posting feeler gage numbers for gaps along the shaft/yokes/space, they were not the same all the way around. Now, on our machine with wear in the bushings it could easy enough be the gap measurements are distorted by the shaft bushing wear.

My opinion is, if the line bore folks are worth a shit, they've got plenty of tricks up their sleeve and getting the boring jig set up perpendicular (two ways) to the "ram guide" really ought to be easy for them to do. The first thing they are going to do is look for machined surfaces pertinent to the job and access their outness.

Your "low tech" solution has inherent problems. You mentioned earlier the machine shop not wanting to (or you not wanting to) take the risk of pre-drilling set screw and/or oil holes because aligning them while seating the bushings was difficult. Off set boring of a centerline is more critical simply because the margin for error is a lot larger. If your set screw/oil holes had not come out perfect (off by 1/4", the set screw would still have held the bushings and the oil/grease would still have reached the shaft).

Have you asked Sid what the end product tolerance on shaft/bushing ought to be as an ideal? Maybe you don't understand this, but having dealt with Sid & Keri, you are now one of their people... giving you help is what they do.

Mike
 
By going this route, I do believe you will end up with everything being tight till youy get down to your Bronze gib . At the very end you will have a very small bit of slop at the bottom of the stroke. Why? With everything being new and tight and in "specs", the difference in the original bushing adjustment has to show up somewhere. I just can't see where it will "disapear". Sumpin to think about or keep in mind. Not a biggy but still there nonetheless. I have those size tolerances all over mine :-)
 
Hey Guys. I didn't get to the machine shop yesterday. I will go today.
I believe Sid told me that the shaft to bushing tolerance was .003 to .004, which he considered a standard tolerance for shafts and bushings, but I would have to ask again to be sure.

The bushings do sometimes rotate a little as they are installed. Especially the back one which is tapered. I assume that it is a function of the taper and the turning pressure on the device used to press them. In my case, a 1/2" impact wrench. Threading a hole in the bushing and trying to exactly line up threads in the casing with threads in the bushing would be an absolute exact job, while pressing in a bushing that has been drilled off center would not require nearly the same exactness.

I wish that I had known of the line-boring equipment being available in the beginning, because I would surely have chosen that option. That would have guaranteed a proper fit, if the operator was skilled. However, now I am at this point with one bushing installed and fine and one remaining. I assume the line-boring guy would need to start with two blank bushings. I may call them and ask. The people who have it are a heavy equipment sales place.

I understand that I will have some play in the whole mechanism in the end. I expect that. I am just trying to minimize it. I decided a long time ago that when I work on stuff I will try for perfection and accept what I get. If you accept all kinds of error along the way of a project, often the end result is unacceptable when all of the error adds up in the end. The approach can seem very nit-picky along the way but worth it in the end.
 
I sure understand the search for perfection and the reality of the end product. To me, it's the only way to deal well with anything, especially something that is as much of an unknown as these hammers are.

I guess I don't think the bushing lock set screw needs a threaded hole to be permanently effective in keeping the bushing from turning. Really, the set srew has a cup-end designed to upset a small amount of metal, tightly formed to the cup form. Might be I don't understand something here but if the set screws are kept tight I don't see how it's possible for a bushing to move.

Mike
 
Yeah, one of the things I really like about this thread is all the good pictures of various Fairbanks and the parts.

Mike
 
I probably agree that the set screws for the bushings don't need to be threaded, and they don't need to go all the way through the bushings (and shouldn't), either. I will probably just drill them part way through and not thread them.

I talked to the machine shop today. We kicked things around and agreed to think about it some more. Probably, we are going to try to bore the back bushing off center, if they can come up with a good way to do it. It is a little complicated, since it is tapered as well.

The machinist realized that the key way in the middle of the shaft under the sleeve is kind of useless, since there is no way to reassemble the shaft and sleeve over it between the yokes with a key in it. The shaft is one diameter now, when it used to step down all the way from the drive pulley out the back. A key could be inserted with the narrower stepped-down shaft, but not now. We will probably use the key slot to hold the ends of the two bolts that will hold the sleeve in place.

I realized that the key slot in the end of the shaft that will hold the drive pulley in place was not long enough. The machinist was going to hang the pulley out on the end of the shaft, but that would shift my motor and pulleys farther out from the back of the hammer another inch or so, and there would have been a gap between the rear yoke and the drive pulley. He is going to extend the key slot all the way from the end of the shaft to the end of the rear bushing.

There is really a great deal of planning and conversation necessary to do this. The machinist doesn't understand the hammer setup as much as I do, since I have lived with it and disassembled the hammer, and I have no idea of the reality of machining parts.

I will try to keep pictures coming, since I realize they speak better than I do, and they are certainly more interesting. Bruce, if line boring is done, I will definitely get you pictures. I hope all this leads to you guys understanding your hammers better, as well as mine getting rebuilt.
 
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