jthibodeau89
Gold Member
Thanks for the RR Warner link. I had not heard of them. Don't do much 'smithing. Great reference.
Repairing sheared impeller shaft - JD 47 snowblower attachment
- Thread starter DanMc77
- Start date
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al3
Silver Member
DanMc Did you ever check your input side chain gear (big one) for concentricity? My original was bad and all of the OEMs replacement the dealer offered up were welded off center, some by a lot. As long as things are apart and the lathe is warm.......
Put me in the I like HSS club. One misstep with that $35 (and up) DMNG insert and ******pooof*****. The time is money economics and the need for thru- put pressures thankfully stop at my hobby shop door. Sometimes nice to have a more elastic cutting tool making chips.
Learning how to shape and sharpen HSS is a skill that keeps on pay back. Not to mention the ability to form custom shapes, at least on low carbon and the like.
And yes, in the drawer are a few indexables for use when needed.
Put me in the I like HSS club. One misstep with that $35 (and up) DMNG insert and ******pooof*****. The time is money economics and the need for thru- put pressures thankfully stop at my hobby shop door. Sometimes nice to have a more elastic cutting tool making chips.
Learning how to shape and sharpen HSS is a skill that keeps on pay back. Not to mention the ability to form custom shapes, at least on low carbon and the like.
And yes, in the drawer are a few indexables for use when needed.
The radius gauges came in and I just checked, my manually-turned fillet is between 2.25 and 2.50. I measured the bearing and it's coming in at 1.5.
The bearing is a Timken L44643. The spec is here: Part Number L44643, Tapered Roller Bearings - Single Cones - Imperial On The Timken Company
I think I need to look at this parameter:
R - Cone Backface "To Clear" Radius3
0.050 in
1.270 mm
So in either case, the fillet on my shaft is too large and would explain why I didn't get the bearing to seat.
To Al3's question: "Did you ever check your input side chain gear (big one) for concentricity?" I'm a bit confused by that question. This blower has a drive shaft with 2 U joints that comes in from the tractor. That drive shaft connects to the other smaller gear shaft and drives this gear to reduce the RPM going to the impeller. There's no chain. I know that some of the JD blowers do use a chain in place of a gearbox. When I put the gear into the 4 jaw chuck, I was able to indicate on the small remnant of the original shaft, and also on the side of the gear. Unfortunately, the side of the gear was machined with a very coarse feed, so when indicating on that, I had to adjust it until the "runout" was minimized. I have not chucked the shaft and checked the tops of the gear teeth to estimate concentricity, but I think you're talking about a sprocket for a chain.
The bearing is a Timken L44643. The spec is here: Part Number L44643, Tapered Roller Bearings - Single Cones - Imperial On The Timken Company
I think I need to look at this parameter:
R - Cone Backface "To Clear" Radius3
0.050 in
1.270 mm
So in either case, the fillet on my shaft is too large and would explain why I didn't get the bearing to seat.
To Al3's question: "Did you ever check your input side chain gear (big one) for concentricity?" I'm a bit confused by that question. This blower has a drive shaft with 2 U joints that comes in from the tractor. That drive shaft connects to the other smaller gear shaft and drives this gear to reduce the RPM going to the impeller. There's no chain. I know that some of the JD blowers do use a chain in place of a gearbox. When I put the gear into the 4 jaw chuck, I was able to indicate on the small remnant of the original shaft, and also on the side of the gear. Unfortunately, the side of the gear was machined with a very coarse feed, so when indicating on that, I had to adjust it until the "runout" was minimized. I have not chucked the shaft and checked the tops of the gear teeth to estimate concentricity, but I think you're talking about a sprocket for a chain.
al3
Silver Member
Yes, I was errantly thinking about the models with the chain drive front end. Sorry for the confusion.
This is kind of a bittersweet post. My task is completed. The radius gauges were used to grind a cutter to about 1.25 mm radius. The gear was chucked into the 4 jaw and aligned. The proper radius was cut on each side of the gear. Bearings were heated up to about 200 degrees on the stove and slipped on. The bearing on the OUT side with the long shaft did not seat perfectly, with a .010" gap in the back. The in side was nice and flush. Before I spent the effort to pull the bearing off, I figured I might as well put it together and see whether it binds up. The final gearbox assembly is as perfect as I could ask for. There's a barely perceptible amount of movement in the bearings and no binding up at all. So the .010" of space behind the output bearing is not an issue. The smaller gear has a bit of slop in its bearings. Everything works nice and smoothly. Ship it.
The next big test is for my neighbor to put it in his snow blower and see if he can break it. I told him that this was an experiment for me and the only pay I need is a handshake. Actually, he does a small amount of snow-clearing for me at no charge, so this is my way of saying thanks.
I also need to say thank you to everybody that offered their knowledge and skills. I think it's unlikely that I would have been successful without your help, especially to jthibodeau89 who laid out the whole process in one paragraph.
I'll post some pics or a video to show it at work in a few weeks - or - when there's more snow. The snowfall this year has been quite sparse.
The next big test is for my neighbor to put it in his snow blower and see if he can break it. I told him that this was an experiment for me and the only pay I need is a handshake. Actually, he does a small amount of snow-clearing for me at no charge, so this is my way of saying thanks.
I also need to say thank you to everybody that offered their knowledge and skills. I think it's unlikely that I would have been successful without your help, especially to jthibodeau89 who laid out the whole process in one paragraph.
I'll post some pics or a video to show it at work in a few weeks - or - when there's more snow. The snowfall this year has been quite sparse.
jthibodeau89
Gold Member
Congratulations on completing your project! You never know what you can do until you decide to get dirty and give it a go. Glad i could help.
jthibodeau89
Gold Member
Got any snow yet?
Today we installed the rebuilt gearbox in my neighbor's machine. It's working very nicely. This video is the first time he pushed it into snow. After this, he ran it around and pushed it a little harder with no issues.
JD Model 47 Snowblower - Re-machined impeller shaft after shearing off. - YouTube
JD Model 47 Snowblower - Re-machined impeller shaft after shearing off. - YouTube
jthibodeau89
Gold Member
Looks great! It is snowing here this evening. Bit i dont think i need a blower yet....lol. The weather guessers are saying we may get all of 1", and it won't stick to the roads. Just enough to make the fields white, and the horses want to play....