Re: new spindles - old pulleys. Fit problem?
I think I would use some locktight....
I think I would use some locktight....
new spindles - old pulley problem. (Pics & CAD drawings !)
Hmmm...
a) After several months, rain is once again falling here on California's Central Coast.
b) Suddenly I seem compelled to make my first post on MTF.
Hey, it's probably just one of those 'strange coincidence' things, right?
Anyway, some while back, I acquired my first "fixer" and promptly dove in to the deep end of the MTF pool in my quest for total lawn tractor enlightenment. Wow! What an amazing storehouse of knowlege and experience. Thank-you, thank-you! Found lots of great info; made some significant repairs; and even stared down perhaps the most terrifying thing ever to haunt MTF - yes I'm talking about that icon of pure villainy and voodoo... the Variator. On the brighter side, I also made a new "best friend" down the street - a very friendly, retired gentleman who has four different welders in his shop, knows how to use them all, and enjoys helping people out with a project now and then. (seriously, how perfect is that!)
Well then the first part of that 'coincidence thing' occurred, and I suddenly felt "inspired" to finish rebuilding and installing the deck. That's where I ran into a little glitch. Fortunately for me, even with the massive sleep deprivation caused by spending waaay too much time on the forum, I still managed to remember MTF's MOST important lesson on problem solving:
You Want Pictures! :sidelaugh
So, in a blatant and slavish attempt to curry favor and get responses to my questions, here are some pics. (with my questions accompanying the last image.)
First two are just after getting 'it' home - an MTD 600 series w/ B&S 12hp IC. Needed battery and ignition work at minimum. Not too bad from a rust standpoint, compared to places where you guys have *real* weather. Had been stored in a garage for the past 4 years or so as well. (clearly not very well maintained before that though.)
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Dump Cart. Also got a complete Grass Collector attachment. (no pic for that)
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Here's a shot after some minor disassembly and a lot of pressure washing.
![]()
begin next phase of disassembly and cleaning
![]()
example of "not well maintained" (before and after)
![]()
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Ok, on to my fit questions. The spindles and bearings on the deck were pretty far gone, so I went with the low-cost replacements from mowtownusa after noting favorable reviews. (we get virtually no rain for more than half the year, so use will be fairly light.) Using the "Deck G for 600 Series Lawn Tractors" manual, I ordered replacements for spindle assembly - part# 717-0906.
Here's a model I made to show the (blade)spindle (with pulley) design used on my deck.
![]()
The replacement spindles seemed to be identical to the originals when I compared them, so I figured I was good to go. Well, after resuming work on the deck last week, the spindle plates fit the deck perfectly and the blades installed with no problem - I had to buy one new coupler, and both the old and new coupler made a nice snug fit - tapped on with small hammer and wood block (blade side) - on the new spindles. So far, so good. (blade end not shown in the model)
The pulley side however, is a different story. Both pulleys seem to fit a bit loose where the toothed(?) sections of pulley and spindle interlock - they definitely interlock, but the fit is certainly not snug. But worse than that is that the pulley sleeves bottom out against the spindle bearing before the shoulder sections of shaft and sleeve make contact. Which means if I tighten down the pulley, it binds against the bearing. After doing some measuring, it seems like the mismatch is only about 0.1" or so, but more than enough to be a problem. (Unfortunately, I tossed the old spindles a while back, so I can't do any precise measurement and fit comparisons at this point. Doh! :00000061
So...
a) do pulleys typically fit a bit looser than blade couplers, but are fine once they're tightened down? (assuming they're not pressing on the bearing.) I presume they would be well aligned with the spindle shaft once the internal shoulder is firmly seated on the shaft.
b) if yes for 'a', can I just grind an 1/8" off of each sleeve and install the pulleys? (balance shouldn't be a concern with such a small diameter involved.)
I'm assuming that with two bearings pressed on those spindle shafts, that moving each of them 'just a bit' isn't happening without a serious press and other jigs to do it properly. There *is* about 3/16 of shaft length exposed on the blade side, if it could be done.
c) pulleys should fit snug, just like the blade couplers; order new ones from same source with expectation that they should fit properly or allow a return.
- or -
d) Newbie Alert! 'Your view of the forest is blocked by the trees, Grasshopper.'
Thanks,
Gary
a) After several months, rain is once again falling here on California's Central Coast.
b) Suddenly I seem compelled to make my first post on MTF.
Hey, it's probably just one of those 'strange coincidence' things, right?
Anyway, some while back, I acquired my first "fixer" and promptly dove in to the deep end of the MTF pool in my quest for total lawn tractor enlightenment. Wow! What an amazing storehouse of knowlege and experience. Thank-you, thank-you! Found lots of great info; made some significant repairs; and even stared down perhaps the most terrifying thing ever to haunt MTF - yes I'm talking about that icon of pure villainy and voodoo... the Variator.
On the brighter side, I also made a new "best friend" down the street - a very friendly, retired gentleman who has four different welders in his shop, knows how to use them all, and enjoys helping people out with a project now and then. (seriously, how perfect is that!)Well then the first part of that 'coincidence thing' occurred, and I suddenly felt "inspired" to finish rebuilding and installing the deck. That's where I ran into a little glitch. Fortunately for me, even with the massive sleep deprivation caused by spending waaay too much time on the forum, I still managed to remember MTF's MOST important lesson on problem solving:
You Want Pictures! :sidelaugh
So, in a blatant and slavish attempt to curry favor and get responses to my questions, here are some pics.
(with my questions accompanying the last image.)First two are just after getting 'it' home - an MTD 600 series w/ B&S 12hp IC. Needed battery and ignition work at minimum. Not too bad from a rust standpoint, compared to places where you guys have *real* weather. Had been stored in a garage for the past 4 years or so as well. (clearly not very well maintained before that though.)
Dump Cart. Also got a complete Grass Collector attachment. (no pic for that)
Here's a shot after some minor disassembly and a lot of pressure washing.
begin next phase of disassembly and cleaning
example of "not well maintained" (before and after)
Ok, on to my fit questions. The spindles and bearings on the deck were pretty far gone, so I went with the low-cost replacements from mowtownusa after noting favorable reviews. (we get virtually no rain for more than half the year, so use will be fairly light.) Using the "Deck G for 600 Series Lawn Tractors" manual, I ordered replacements for spindle assembly - part# 717-0906.
Here's a model I made to show the (blade)spindle (with pulley) design used on my deck.
The replacement spindles seemed to be identical to the originals when I compared them, so I figured I was good to go. Well, after resuming work on the deck last week, the spindle plates fit the deck perfectly and the blades installed with no problem - I had to buy one new coupler, and both the old and new coupler made a nice snug fit - tapped on with small hammer and wood block (blade side) - on the new spindles. So far, so good. (blade end not shown in the model)
The pulley side however, is a different story. Both pulleys seem to fit a bit loose where the toothed(?) sections of pulley and spindle interlock - they definitely interlock, but the fit is certainly not snug. But worse than that is that the pulley sleeves bottom out against the spindle bearing before the shoulder sections of shaft and sleeve make contact. Which means if I tighten down the pulley, it binds against the bearing. After doing some measuring, it seems like the mismatch is only about 0.1" or so, but more than enough to be a problem. (Unfortunately, I tossed the old spindles a while back, so I can't do any precise measurement and fit comparisons at this point. Doh! :00000061
So...
a) do pulleys typically fit a bit looser than blade couplers, but are fine once they're tightened down? (assuming they're not pressing on the bearing.) I presume they would be well aligned with the spindle shaft once the internal shoulder is firmly seated on the shaft.
b) if yes for 'a', can I just grind an 1/8" off of each sleeve and install the pulleys? (balance shouldn't be a concern with such a small diameter involved.)
I'm assuming that with two bearings pressed on those spindle shafts, that moving each of them 'just a bit' isn't happening without a serious press and other jigs to do it properly. There *is* about 3/16 of shaft length exposed on the blade side, if it could be done.
c) pulleys should fit snug, just like the blade couplers; order new ones from same source with expectation that they should fit properly or allow a return.
- or -
d) Newbie Alert! 'Your view of the forest is blocked by the trees, Grasshopper.'
Thanks,
Gary
1 - 9 of 9 Posts
Re: new spindles - old pulleys. Fit problem?
Chagrin -
It's not a diameter thing. (well ok, the 'not a snug fit' part is, but that's minor compared to the main problem.) Here's another view that should help.
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Despite what I described as a 'less than snug' fit with the splines, there is *plenty* of overlap where the shoulders should seat against each other. They just don't make contact before the pulley hits the bearing. So it's a *length* (mismatch) issue between pulley and spindle shaft. From measuring, my estimate was that the pulley sleeve only needed to be ~0.1" shorter. That's why my idea was to just grind a bit off the end of each sleeve.
To clarify a bit more on the 'fit' part - if "wood block, hammer and a bit of force required" represented 100% overlap (or interface) between the splined sections, then I'd call my fit a 95% (as a description, not actual measurement). As I'm sure you know, it doesn't take much at all for something like that to feel loose, but it's not like I have splines that are barely overlapping. (That's also why I said there should be plenty of contact for the shoulders - IF they get there.)
Maybe I'll just go ahead with my "mod" and see if it works. I just figured I'd check to see if anyone else had encounterd this, or see if I was completely missing a different solution.
Gary
Chagrin -
It's not a diameter thing. (well ok, the 'not a snug fit' part is, but that's minor compared to the main problem.) Here's another view that should help.
Despite what I described as a 'less than snug' fit with the splines, there is *plenty* of overlap where the shoulders should seat against each other. They just don't make contact before the pulley hits the bearing. So it's a *length* (mismatch) issue between pulley and spindle shaft. From measuring, my estimate was that the pulley sleeve only needed to be ~0.1" shorter. That's why my idea was to just grind a bit off the end of each sleeve.
To clarify a bit more on the 'fit' part - if "wood block, hammer and a bit of force required" represented 100% overlap (or interface) between the splined sections, then I'd call my fit a 95% (as a description, not actual measurement). As I'm sure you know, it doesn't take much at all for something like that to feel loose, but it's not like I have splines that are barely overlapping. (That's also why I said there should be plenty of contact for the shoulders - IF they get there.)
Maybe I'll just go ahead with my "mod" and see if it works. I just figured I'd check to see if anyone else had encounterd this, or see if I was completely missing a different solution.
Gary
Ahhh... now I understand *your* point, which makes perfect sense as long as the bearing's inner race is supported on the opposite side.
Only one (BIG!) problem here. Apparently, mine isn't. When I start to tighten down the nut and lockwasher, if I spin the blade I can feel the bearing friction increase noticeably **before I even fully compress the lockwasher!** (I'm using the nut and lockwasher that came off the old spindle, and they match the description in the 'Deck G' manual. The lockwasher is *quite* stout; about 5/32 thick.) I didn't continue on to anything near normal torque, as I had the distinct impression I'd really be binding up the bearing and probably causing damage.
I did check again just now, and the pulley cleanly contacts the innner race without pressing against any other portion of the bearing, so there doesn't seem to be any mis-alignment issue.
It seems to me that if the thrust forces along the spindle axis were all that significant during operation, then tapered roller bearings would be necessary in these spindles. Given the amount of force (typically) needed to press these bearings onto a shaft, along with the other flange (the gold portion in my model) that also appears to be pressed onto the bearing, I would think that would be sufficient to keep the bearings in place. But then, I'm not a machinist or a bearing expert, so what do I know?
Aaaaarrrgghh! Someone here has to have a clear answer on this. Maybe tomorrow I'll see if I can contact the place where I bought the spindles, and get them to put one of their replacement pulleys on the same spindle and see if it reaches the bearing.
Ok, I have to stop now and go write on the blackboard 1,000 times: "Never toss the old part, until the new part is installed. Never toss...." :banghead3
Your efforts to help are much appreciated.
Gary
Only one (BIG!) problem here. Apparently, mine isn't. When I start to tighten down the nut and lockwasher, if I spin the blade I can feel the bearing friction increase noticeably **before I even fully compress the lockwasher!** (I'm using the nut and lockwasher that came off the old spindle, and they match the description in the 'Deck G' manual. The lockwasher is *quite* stout; about 5/32 thick.) I didn't continue on to anything near normal torque, as I had the distinct impression I'd really be binding up the bearing and probably causing damage.
I did check again just now, and the pulley cleanly contacts the innner race without pressing against any other portion of the bearing, so there doesn't seem to be any mis-alignment issue.
It seems to me that if the thrust forces along the spindle axis were all that significant during operation, then tapered roller bearings would be necessary in these spindles. Given the amount of force (typically) needed to press these bearings onto a shaft, along with the other flange (the gold portion in my model) that also appears to be pressed onto the bearing, I would think that would be sufficient to keep the bearings in place. But then, I'm not a machinist or a bearing expert, so what do I know?
Aaaaarrrgghh! Someone here has to have a clear answer on this. Maybe tomorrow I'll see if I can contact the place where I bought the spindles, and get them to put one of their replacement pulleys on the same spindle and see if it reaches the bearing.
Ok, I have to stop now and go write on the blackboard 1,000 times: "Never toss the old part, until the new part is installed. Never toss...." :banghead3
Your efforts to help are much appreciated.
Gary
1 - 9 of 9 Posts
