What's new
What's new
By:
Advanced search…

Is this yoke cast on directly on the end of the shaft? Pellet Mill

B

Bill in PA

Hot Rolled
Joined
Jan 25, 2011
Location
Fairfield, PA
Hello,

Customer wants me to make a replacement yoke to fit on an existing shaft. He gave me two to work with. He does not know how the yoke is joined to the shaft. I could see no joints or seams so I bored into the end of the yoke. Found no seams except for a small void, about the size of a marble about 1" deep about on center. I thought maybe that this was end of the shaft. Continue to bore to the depth of the yoke, about 3" deep and 4" diameter (the shaft is 5" round). Found nothing. Put the shaft in the band saw and cut the yoke off. Appears to be one-piece.

The yoke appears to be cast steel. The shaft may be 1045. Cuts easy but does have hard spots where a bearing was torched off. No hard spots while boring/facing. No trouble cutting with the band saw.

In the photo of the end of the shaft, you can see a seam. That is a ring that is pressed on. You can see it on the other shaft where I knocked it off.

Any thoughts would be great about how this was manufactured.

Photos are of a brand new shaft assembly, 2nd used shaft assembly, sawed-off yoke and shaft.

Thanks,

Bill

IMG_7405.jpgIMG_7419.jpgIMG_7392.jpgIMG_7413.jpgIMG_0875.jpg
 
Looking at both, I would say one piece casting. I'm going to say that if they were two piece, the section would be very thin around the shaft and prone to cracking. You'd have a lot of time in welding that by the time you notched in from either side.

Material is probably WCB or WCC. We used to do a lot of stuff like that, now it all comes from China.
JR
 
Bill in PA said:
I guess the whole thing could be cast steel, but I did not get that impression since the shaft can be hardened.

Bill
Click to expand...

Metallurgist with polished sections, etching prep, high magnification might find a seam. Mark One eyeball, not.

Is it old enough - predating GOOD casting of steels - that upsetting and hot forging is a possibility?
High stress, that was once pretty much standard.
 
JRIowa said:
Looking at both, I would say one piece casting. I'm going to say that if they were two piece, the section would be very thin around the shaft and prone to cracking. You'd have a lot of time in welding that by the time you notched in from either side.

Material is probably WCB or WCC. We used to do a lot of stuff like that, now it all comes from China.
JR
Click to expand...

Thanks for the reply. I don't normally deal with cast parts and I am ignorant of the processes, etc.

Bill
 
Talked with the customer this afternoon. He said the OEM says that the shaft and yoke are two pieces but only sold as a one-piece unit.

$11,000 for this part. They were hoping to save a little and just replace the yoke.

Bill
 
Bill in PA said:
Talked with the customer this afternoon. He said the OEM says that the shaft and yoke are two pieces but only sold as a one-piece unit.

$11,000 for this part. They were hoping to save a little and just replace the yoke.

Bill
Click to expand...

Could work. Original might NOT have been two-piece, but is now. Joining is the critical point, but welding technology, plus better understanding and ability to affordably control post-weld heat-treat has come a long way, last many years. That could be why they don't sell it separate. Expectation a field repair shop won't match the bond.

I've seen that sort of design change made by the maker in mining machines - same reason.

They didn't have any but mechanical means to fasten an Aluminum Bronze sliding end hub with internal splines to a tubular steel driveshaft of a 100 HP DC motor. And then they did.

Even if it ends up with but half the life in service, at say 25% to 50% of that 11 large, initial cost, and another thousand or so worth of labor, more frequent change?

Whole machine might be taken out of service before it next fails, overall economy as unpredictable as it can be.

Grab yer undershorts, pull a "wedgie" to stay focussed, go quote the Mike Foxtrot.

:)
 
Monarchist said:
Could work. Original might NOT have been two-piece, but is now. Joining is the critical point, but welding technology, plus better understanding and ability to affordably control post-weld heat-treat has come a long way, last many years. That could be why they don't sell it separate. Expectation a field repair shop won't match the bond.

I've seen that sort of design change made by the maker in mining machines - same reason.

They didn't have any but mechanical means to fasten an Aluminum Bronze sliding end hub with internal splines to a tubular steel driveshaft of a 100 HP DC motor. And then they did.

Even if it ends up with but half the life in service, at say 25% to 50% of that 11 large, initial cost, and another thousand or so worth of labor, more frequent change?

Whole machine might be taken out of service before it next fails, overall economy as unpredictable as it can be.

Grab yer undershorts, pull a "wedgie" to stay focussed, go quote the Mike Foxtrot.

:)
Click to expand...

They brought a pellet mill out of storage that was built in the 1930's and installed it last year. I had to make some parts that were missing. They have a good international business making animal feed for zoos, aquafarms, and such.

You can see in the photo of the new shaft that the area around the bolt holes is thicker. That is the weak spot in the old shafts. If I were to machine new yoke, they wanted as much material left in that area as possible.

Bill
 
Bill in PA said:
They brought a pellet mill out of storage that was built in the 1930's and installed it last year. I had to make some parts that were missing. They have a good international business making animal feed for zoos, aquafarms, and such.

You can see in the photo of the new shaft that the area around the bolt holes is thicker. That is the weak spot in the old shafts. If I were to machine new yoke, they wanted as much material left in that area as possible.

Bill
Click to expand...

On a machine that old, it could justify altering a few bits. If room for a larger diameter bearing, up close to the flange, then a larger diameter shaft end and joining could extend the life substantially.

I'm holding with upset and forged. Steel castings large flange, slender shaft in the 20's and 30's were still a black art, attractive but hard to master in large sections. Think 1903-A3 Springfield rifle receiver size. Then try to scale that up and make the cooling work out to leave it strong. Forging was still the road most traveled, motor vehicle driving axles a close example.

US Steel had a film back in the day showed how they insured radial flow grain so high speed wheels for railroads lived longer. Started with a slug about the size of a ten gallon paint bucket. Hot upset it to rough hub and wheel shape more than double the diameter as if it were nothing harder to work than common bread dough.

Technology still exists. Improved upon, even. But where, nowadays, can you book the press?

Or whom is it makes an affordable car, truck, ag, or Earth-mover axle as might serve to be modified?
 
Monarchist said:
On a machine that old, it could justify altering a few bits. If room for a larger diameter bearing, up close to the flange, then a larger diameter shaft end and joining could extend the life substantially.

I'm holding with upset and forged. Steel castings large flange, slender shaft in the 20's and 30's were still a black art, attractive but hard to master in large sections. Think 1903-A3 Springfield rifle receiver size. Then try to scale that up and make the cooling work out to leave it strong. Forging was still the road most traveled, motor vehicle driving axles a close example.

US Steel had a film back in the day showed how they insured radial flow grain so high speed wheels for railroads lived longer. Started with a slug about the size of a ten gallon paint bucket. Hot upset it to rough hub and wheel shape more than double the diameter as if it were nothing harder to work than common bread dough.

Technology still exists. Improved upon, even. But where, nowadays, can you book the press?

Or whom is it makes an affordable car or truck axle as might serve to be modified?
Click to expand...

In case it is of any interest, I attached 2 scans of the old pellet mill that I mentioned. This one is a bit smaller than the one that the shaft in question is for. They have multiple extruder lines and I don't know which one the shaft in question is for. I have not been through the whole place.

For scale, part 1061 is 16" in diameter (this was the missing part I supplied). Part 1009 is the equivalent shaft in the smaller mill.

Also attached is a photo of the equivalent to part 1029 for the larger mill.

Bill

CCI02082018.jpgCCI02082018_0001.jpgIMG_7381-001.jpg
 
I've worked on similar parts years ago, from the alfalfa pelleters that used to be around here. IIRC, those parts were one piece and of nodular iron, so arc welding was not a recommended repair, only metallizing was acceptable for repairing the bearing journals on the main shaft. So I don't know how you can attach a new head on that thing, I'm not sure it is practical to attempt.
 
You must log in or register to reply here.

Similar threads

avivz
Schaublin 135 rebuilding project- ongoing thread
3 4 5
Replies
83
Views
5K
avivz
avivz
C
lathe brake issue or is this normal
Replies
11
Views
355
Vecair
Vecair
I
getting out a blind hardened dowel pin...suggestions?
2
Replies
37
Views
2K
D Nelson
D Nelson
T
How remove the Piston on the Mill drive shaft Mazak QTN 200
Replies
1
Views
397
Timbodidg
T
W
Wedge fastener on JA Fay saw shaft, methods for removal?
Replies
1
Views
275
Joe Michaels
J








 

ABOUT PRACTICAL MACHINIST

With more than 10.6 million unique visitors over the last year, Practical Machinist is the most visited site for metalworking professionals. Practical Machinist is the easiest way to learn new techniques, get answers quickly and discuss common challenges with your peers. Register for the world’s largest manufacturing technology forum for free today to stay in the know.

Learn more about us.

STAY CONNECTED

Facebook Instagram YouTube LinkedIn Pinterest Twitter Tiktok

Register Become a forum member. Register today.

Sign Up Sign up for our e-newsletter.

© 2024 Copyright Practicalmachinist.com. All Rights reserved.

Back
Top