A little Machinist advice please

[AndyM]

Is that a JS or JA 65 series mower? If so, just get rid of it. Deere's venture into mass marketing, and they failed with those too.

The JX/JE series and 14SB mowers, however, have been awesome, just expensive. I buy them from time to time and give them to folks who need them. I used to make a good bit of money on them, because a lot of people were still paying top dollar for clean ones. That kind of sunsetted and I generally just give them away now. Always get to work on them, though...general servicing is about all they ever need. Blade here and there and an occasional blade brake clutch on the rougher used ones. I still have two of them, I keep the bad one and my mom is getting the other one which looks cuts runs like a brand new one.

JX 75 - good mower with a Kawasaki engine, aluminium deck (good and bad). Just this pulley issue.

 

[lugbolt]

JX 75 - good mower with a Kawasaki engine, aluminium deck (good and bad). Just this pulley issue.

make sure the nut isn't bottoming out on the shoulder of the shaft. If it does, the pulley won't be tightened up fully. and destroys the pulley. We always used an axle washer under the pulley to help tighten it up.

 

[torch]

So, my question - any hope of fixing this? Alas I did not buy that metal lathe 10 years ago so I am limited in my fabrication abilities but I can get pretty creative. Any hope here or just chin up and buy a new one?

View attachment 155604 View attachment 155605

How are you at welding?

Princess Auto has a line of weld-on pulleys. You match the appropriately sized hub with the required diameter/width of pulley and weld the two together. The hub is indexed to ensure concentricity.

 

[AndyM]

Lugbolt
There IS some scoring on the bottom of the hub - I think your on to something by gum. Noted and now part of a plan.

Torch
I did have a look at Princess but must not have looked closely enough. My welding is a little artistic (not in a good way) but does stick. I will look again.

Thanks gents.

 

[torch]

Torch
I did have a look at Princess but must not have looked closely enough. My welding is a little artistic (not in a good way) but does stick. I will look again.

Pulleys: https://www.princessauto.com/en/weld-on-pulleys/product/PA1000001341

Hubs: https://www.princessauto.com/en/w-series-weld-on-hubs/product/PA1000001384

IIRC, the hub "series" refers to the index diameter. It needs to match the hole diameter of the chosen pulley. I believe all those pulleys take the W series hubs I linked to. They have other series hubs as well, but I think those are for the weld-on sprockets .

 

[AndyM]

Pulleys: https://www.princessauto.com/en/weld-on-pulleys/product/PA1000001341

Hubs: https://www.princessauto.com/en/w-series-weld-on-hubs/product/PA1000001384

IIRC, the hub "series" refers to the index diameter. It needs to match the hole diameter of the chosen pulley. I believe all those pulleys take the W series hubs I linked to. They have other series hubs as well, but I think those are for the weld-on sprockets .

Thanks Torch - looks like a real possibility if I kind find a 10 mm hub - and I think PoTreeBoy listed one earlier - if it fits.

 

[torch]

Thanks Torch - looks like a real possibility if I kind find a 10 mm hub - and I think PoTreeBoy listed one earlier - if it fits.

If you can't find a 10mm one (and you are sure it's 10mm) send me a PM.

 

[PoTreeBoy]

Thanks Torch - looks like a real possibility if I kind find a 10 mm hub - and I think PoTreeBoy listed one earlier - if it fits.

That's what I was 'shade-treeing' in post 10. I couldn't find a 10 mm weld hub.

Edit: post 18

 

[torch]

I have a lathe. Do you have digital calipers?

 

[AndyM]

Torch - how's this:

I double checked the shaft on both units (the shaft in the mower and the original I replaced). I call it 10 mm - but maybe not..

 

[AndyM]

That's what I was 'shade-treeing' in post 10. I couldn't find a 10 mm weld hub.

Edit: post 18

Sorry to hear that - the joys of metric. Makes you wonder why JD would use it (this mower was bought over 20 years ago).

 

[torch]

Sorry to hear that - the joys of metric. Makes you wonder why JD would use it (this mower was bought over 20 years ago).

Kawasaki engine?

That's a 10mm shaft all right. Oddly, a 10mm shaft normally uses a 3mm key but scaling your first image in post 1, that appears to be a 2mm keyway.

It also appears from the above pictures that the shaft is recessed into the casting so the pulley hub OD has to fit inside to butt against the shaft when the retaining nut is tightened. Again, scaling from the original photo, the pulley hub OD looks to be about 14mm? Recessed perhaps 2-3 mm?

How long is it from the end of the hub where it butts against the shaft to the near face of the pulley?

 

[torch]

I'm thinking you need something like this, if you can find an appropriate size weld-on pulley @ Princess Auto:

Needs some depths though. (I converted the diameters listed on the PA website to metric).

The smallest diameter pulley listed @ PA is 3-1/2" OD. Your pictures don't show the full OD of yours, but I'm guessing it's about 3" to 3-1/2"? Would a slightly larger pulley fit in there? Is there enough belt adjustment available to accommodate one?

 

[AndyM]

Yup a Kawasaki engine with JD on top.

I took some additional pics if the existing hub - hopefully that helps. It is a 3 1/2 hub 3/8 belt. Not sure I would try to go bigger - it's a fairly tight as it is.

There is a pic of the shaft with the key at 11.5 mm so less the shaft of 10 mm edit (orig said 9.0 ???) leaves a 1.5 mm (orig said 2.5) mm key I assume.

 

[torch]

Yup a Kawasaki engine with JD on top.

I took some additional pics if the existing hub - hopefully that helps. It is a 3 1/2 hub 3/8 belt. Not sure I would try to go bigger - it's a fairly tight as it is.

There is a pic of the shaft with the key at 11.5 mm so less the shaft of 9.0 leaves a 2.5 mm key I assume.

Measure the width of the key. I've never come across a 2.5mm key, AFAIK it goes from 2mm to 3mm. The depth of the keyway is cut so the key is centered on the chord across the two sides of the slot, not the radius.

So a 3mm key would have a .23mm chord height -- ie: theoretically be set .23mm deeper than 1.5 mm, and the measurement from the opposite side of the shaft to the outside of the key would therefore be 11.27mm.

A 2mm key would have a .1mm chord height, resulting in a 10.9mm overall measurement, so that pretty much rules out a 2mm key though.

 

[torch]

Adding in your measurements (and assuming for the moment that the weld-on pulley is the same thickness as your pulley at the hub and the key is 3mm wide) we get:

 

[AndyM]

Adding in your measurements (and assuming for the moment that the weld-on pulley is the same thickness as your pulley at the hub and the key is 3mm wide) we get:

View attachment 156083

Hi Torch
Attached is a picture of the key width which I measure as 3.20 - likely the 3 mm you refer to. I also tried to measure how proud the key was from the shaft at 2.03 mm. That's pretty suspect if the shaft is 10 and the aggregate is 11.5 as shown earlier something does not add up but sounds like you have that all figured out.

Does this seem to make sense now?

I should note the 17 x 19 mm shaft seems to ride in a shallow recess on the actual transmission which you can see when you look at the shaft measurement pic earlier. I am assuming the fender washer lugbolt was talking about was riding on the top of the pulley under the nut.

 

[torch]

Hi Torch
Attached is a picture of the key width which I measure as 3.20 - likely the 3 mm you refer to. I also tried to measure how proud the key was from the shaft at 2.03 mm. That's pretty suspect if the shaft is 10 and the aggregate is 11.5 as shown earlier something does not add up but sounds like you have that all figured out.

I'm not surprised. Digital calipers tend to lull one into a false sense of accuracy. The display shows a precision of .01mm, but the reality is the best accuracy one can hope for under ideal conditions is +/- .03mm -- and that's between the jaws, the one aspect that can be zeroed out first, when measuring clean flat things.

The accuracy of the internal jaws is worse (but improves somewhat as the hole diameter increases) and the accuracy of the depth gauge is really more of a suggestion than a real measurement when measuring out-of-position against a surface that's curving away from you. It is extremely difficult to hold the calipers perfectly perpendicular in two axis simultaneously. So let us assume they are using the standard listed in Machinery's Handbook for a 10mm shaft -- 3mm.

I should note the 17 x 19 mm shaft seems to ride in a shallow recess on the actual transmission which you can see when you look at the shaft measurement pic earlier.

Yes, I noted that earlier. I allowed 9mm (IIRC) in the above sketch. You should measure that depth to be sure -- the caliper depth gauge accuracy will be sufficient if we add a mm or two for safety.

I am assuming the fender washer lugbolt was talking about was riding on the top of the pulley under the nut.

Yes. His concern is the length of the threads may end up a bit shy of the pulley hub. The washer ensures there's still a thread or two left when the nut is tightened.

So the only other measurement required is the thickness of the actual weld-on pulley where it meets the hub. At a guess, I'd say 3/16" to 1/4" from the photos on PA's website but I've been wrong about such things before -- twice already in just this thread alone!

 

[lynnmor]

Hi Torch
Attached is a picture of the key width which I measure as 3.20 - likely the 3 mm you refer to. I also tried to measure how proud the key was from the shaft at 2.03 mm.

That is a 1/8" key. Calipers are great for rough work, I always find better ways to measure when precision is required.

 

[Yooper]

Is that maybe a woodruff key? https://www.fastenermart.com/files/woodruff-key-dimensions.pdf