Massey 50 and 55 series Mower Deck Pulleys

Ducky

Ducky
Senior Member
I am still working on or better getting back to those dreaded deck pulleys. Broaches are VERY pricey. I need a couple of deck shafts that have good spline but may be unserviceable due to the rest of the shaft being unserviceable. My plan is to use them to build my own broach with those shafts. Any body that send me the first 2 shafts will get a free pulley. Only the splines need to be good. Two people send a single shaft you both get a pulley. I would need the long shaft from the quill that runs the top belt. If they are short ones I will need more than two.
This is the stuff we are working with.
Raw Material.jpgSemi Finished Pulley.jpg
 
That is impressive! Have you thought about making them out of aluminium or may be even steel?

Are you making them out of polyoxymethylene ? Will your material stand up to the high speed of the deck?

I managed to rebuild some pulleys for my deck a couple of years back but my current plan if I ever have troubles again is to use camshaft timing belt pulleys from whatever car engine as long as I have 4 identical and find the correct length timing belt to use with them. That would resolve in steel pulleys which wouldn't wear anymore.
 
Thanks MacWorld for your input.
I spec'ed this material with the supplier and this was there recommendation for this application. If I remember right I believe it is Delrin. I did ask for oil resistance and abrasion resistance qualities. I had to get this stock made because they do not make 41 cog HDT pulleys.
The reason I am attacking this issue this way is to keep things as stock as possible. That way we can still use the remaining good parts like belts and quill shafts.
I have access to a mill and a lathe so I am starting to feel the best way is to make my own broach out of used deck shafts.
 
Indeed Delrin is a trademark name for polyoxymethylene (aka POM), same as Acetal and other brands.

Do you have an indexing table and are you able to lock the spindle of your mill from turning? If so you could grind yourself a tool with the profile of a single spline and use your mill as a slotter to make each splines one by one. In plastics that wouldn't be that hard I think. See a video of Stefan Gotteswinter about this concept

BTW it's not absolutely required to be 41 cog pulleys, in my plan I would get 4 identical pulleys no matter the number of cogs and I would find the appropriate length timing-belt, AFAIK those can be bought by 1 cog increments and for multiple standard width. Wouldn't be that far from original, would upgrade to metal pulleys and the timing belts would be the only remaining wear-prone parts.
 
We use Delrin (POM) in a few applications here just not as timing pulleys, (I'm a Millwright as well), but it holds up quite well when it's not being used against metal. In most cases it's more of a "something has to wear scenario " but here where it's belts on plastic it shouldn't be too bad. From what I've seen & heard for the most part the damage isn't so much wear but due to impact or blades jumping out of time ie slipping belts? I agree with MAC, steel would work as well. Mostly for me we deal with plated or dipped steel timing gears so this is strictly my half a$$ed opinion lol. (I have yet to inspect my old deck by it does turn free but who know what's under the covers lol.) Wish me luck....love watching other's projects, kills me to see the other forums dying off.
 
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IDo you have an indexing table and are you able to lock the spindle of your mill from turning? If so you could grind yourself a tool with the profile of a single spline and use your mill as a slotter to make each splines one by one. In plastics that wouldn't be that hard I think. See a video of Stefan Gotteswinter about this concept

Thanks MacWorld
That crossed my mind but if I am going to make any amount I really think the broach idea is the way to go. Not sure my right arm would stand up. :thumbs:

Thank you to Jason for your input. I bought an 1855 new in 1977 and the failure point was always ripping the cogs off the belt until the pulley got so bad that they would slip under load. Just my experience.
 
I agree slotting isn't ideal for "production"! May be you could machine splines directly to a 1" round bar and make your broach from this, you seem to be able to machine the cogs in the pulleys :)

As for wear on my deck, I repaired it for a friend before the tractor was even mine. IIRC the cogs were worn on both outer pulleys and for whatever reason the center shaft kept sliding downward (!) and was pushed back up a couple of times and it gradually ripped all the inside splines of the center pulley. I bought a new center pulley (450$ CAN back about 10 years... and only 1 of the 5 that were available was running true) as for the outer pulleys they were NLA and, back then I didn't own a lathe. A friend of mine splitted the center pulley in half which gave me one good outer pulley and we use the outside of the second half, bored it and fitted the core of one of the outer pulleys. I could show some pictures if anyone is interested but it's a bit highjacking this thread :)

Keep us updated Ducky, I also enjoy other's projects and like Jason I like forums!
 
Holy crap Ducky a new 1855 in 77???? No better year lol, (I'm a little bias as that's the year I was born lol, today in fact. Man I'd love to find a 77'. My 1655 is a 76'. I'm going to look at a 1855 snapper with a seized engine, supposedly in good shape other wise & mostly garage stored, (he restores cars & old tractors). I love the Massey better but this one seems pretty good but we'll see.
 
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I agree slotting isn't ideal for "production"! May be you could machine splines directly to a 1" round bar and make your broach from this, you seem to be able to machine the cogs in the pulleys :)

As for wear on my deck, I repaired it for a friend before the tractor was even mine. IIRC the cogs were worn on both outer pulleys and for whatever reason the center shaft kept sliding downward (!) and was pushed back up a couple of times and it gradually ripped all the inside splines of the center pulley. I bought a new center pulley (450$ CAN back about 10 years... and only 1 of the 5 that were available was running true) as for the outer pulleys they were NLA and, back then I didn't own a lathe. A friend of mine splitted the center pulley in half which gave me one good outer pulley and we use the outside of the second half, bored it and fitted the core of one of the outer pulleys. I could show some pictures if anyone is interested but it's a bit highjacking this thread :)

Keep us updated Ducky, I also enjoy other's projects and like Jason I like forums!
Good info. Don't feel you are highjacking. I am looking for any info that could get us thru this as cheap as possible.
 
Holy crap Ducky a new 1855 in 77???? No better year lol, (I'm a little bias as that's the year I was born lol, today in fact. Man I'd love to find a 77'. My 1655 is a 76'. I'm going to look at a 1855 snapper with a seized engine, supposedly in good shape other wise & mostly garage stored, (he restores cars & old tractors). I love the Massey better but this one seems pretty good but we'll see.
We still have it. My brother has it and it was repowered with a P 220 Onan back when you could still get them. He uses it for snowplowing and tilling. I used to till 2 acres a year with it and it cut all my grass and blow our snow for many years. Oh it also pull our 2 row corn planter also. Had dual ag thread tires on it because some of the ground we planted on was very sandy. Also had a 48' spray bar on the belly to incorporate herbicide with the tiller.
Onan offered a kit to do it with that included all the parts needed for the conversion. We did have to notch the frame for the starter.
 
Don, I have one center shaft still in a deck, so I'll have to pull it apart to see if the splines look good. Will try to do tomorrow. I think I can come up with a short outside shaft as well.
 
Ducky, I've been showing your concept to my friend who helped me repair my pulleys and he's wondering what you considered about the tolerances for the fit of your splines you want to broach from a original shafts. Using the original part will result in zero tolerance to the fit with the shafts on all surfaces (minor and major diameter and also both sides of each spline) meaning the pulleys would have to be forced onto the shaft for installation. It might work but it might also result in damage to the pulley during installation as a miss-alignment would get the shaft "broaching" the splines again.

We (him and I) often say that tolerances aren't too critical for small tractors parts, it's not like a car moving at 120km/h nor expected to run for a million hours. For this pulley if it is installed in a way that gets them out of center or even the plane of the pulley not perpendicular to the shaft, the timing belts will have one hell of a hard time. It might cause varying tension and/or a tendency of the belt to move up or down. I never counted the ratio in the mower deck gearbox but I think the blades run 1:1 with the engine RPM meaning up to 3600rpm!

On the other hand it must not be too slack as the same problems will happen.

BTW just remembered I have a post on the forum on the repair of my pulleys: Rebuild of MF 1655 mower deck pulley
 
I here what you are saying.
I will have to do a little filing to get that clearance. My other thought is to cut the spline on a piece of 1 " shaft and use it to get that clearance.
I was over at Practical Machinist and determined it is flat root spline. These are the specs. I now have.
25MM shaft. Spline specs are 9 tooth 10/20 DP - 30* Flat Root
There thoughts are we will have a tough time finding that spline on the self. I do have an add over there just in case someone would have one laying around.
 
I am not sure I understand what you are trying to buy? If you start from 1" round stock don't you "simply" have to machine the profile in it?

Again a machining video of one of my favorites channels.

Oh the day I'll have a shaper and/or a mill...
 
OK guys i just got back from PM and the guys over there convinced me this is not worth the price of a special Broach and cutter.

Considering the cost of the broach and the unknown market a gentlemen over there mentioned that I could make the shaft and the pulley cheaper if I made them with a square drive and sell them as a set.

So here is my new plan. I can do this all with our mill and lathe. I will be making these pulleys with a 3/4" square female hole and a shaft with a 3/4" square male, same as the square on the bottom that matches the blade holder. In order to hold down cost it will be possible to weld the spline shut on a good quill and let you guys do your own machining.

What do you guys think.
 
Keep in mind that the shaft must be hardened as much as possible as the lower bearing is a needle bearing riding directly on the shaft (not the best concept IMO but oh well). See here all the trouble I had to go through to fix those shafts (they are NLA) on my deck as the bearings haven't been replaced when they should have Repair to MF 1655 mower shafts

The alternative might be to bore-out the mower spindle castings to insert a bigger needle bearing using a sleeve on the shaft you will sell but that requires quite a lof of modifications. You could use the same size needle bearing with a reduced shank on the shaft at the needle bearing height but you would have to use a new way of getting the blades to turn as the "double square" drive of the blade holder isn't engaging much on the square of the 1" shaft therefore a smaller shaft couldn't be used.

Those mowers aren't of the simplest concept nor easiest maintenance since but damn they work amazingly well. I think building a custom broach, even if out of standard steel would be the simplest and suit your needs to machine the POM, especially since you were able to go through all the hassle of machining the cogs, which I find amazing. That would really be a better-than-original solution that your customers could use straight out of the box.

I think the main question is: are you equipped to machine the shape of the splines in a steel shaft?
 
Keep in mind that the shaft must be hardened as much as possible as the lower bearing is a needle bearing riding directly on the shaft (not the best concept IMO but oh well). See here all the trouble I had to go through to fix those shafts (they are NLA) on my deck as the bearings haven't been replaced when they should have Repair to MF 1655 mower shafts

The alternative might be to bore-out the mower spindle castings to insert a bigger needle bearing using a sleeve on the shaft you will sell but that requires quite a lof of modifications. You could use the same size needle bearing with a reduced shank on the shaft at the needle bearing height but you would have to use a new way of getting the blades to turn as the "double square" drive of the blade holder isn't engaging much on the square of the 1" shaft therefore a smaller shaft couldn't be used.

Those mowers aren't of the simplest concept nor easiest maintenance since but damn they work amazingly well. I think building a custom broach, even if out of standard steel would be the simplest and suit your needs to machine the POM, especially since you were able to go through all the hassle of machining the cogs, which I find amazing. That would really be a better-than-original solution that your customers could use straight out of the box.

I think the main question is: are you equipped to machine the shape of the splines in a steel shaft?
What is your thought on chrome hydraulic shaft. I can get that easy at my brother hydraulic shop.
 
Oh now we definitely are beyond my knowledge :) I know they are hard but I don't know to which extent. At least their surface is really smooth which would be a good thing. Are they the exact diameter that is required for the bearing? If you start machining them you would loose the surface and may be also the hardening as it might be only a certain thickness of the outside.

My main concern, are you able to machine them efficiently? For my hard-faced shafts we were using CBN inserts as carbide inserts wouldn't have been able to cut them.
 
My brother machines this shaft everyday with carbide. Let me check with him as to the Hardness. It can be bought at what ever you spec for diameter.
The only machining operation on the shaft would be to cut the little short square for the mower blade holder and a longer square for the pulley drive and a hole drilled and tapped on either end. I have machined this shaft before with regular carbide mills. Have also found some that would get in a fight with my band saw blade if I did not grind a start though the chrome.
I will talk to my brother tomorrow and get some specs on that shaft. We also have a supplier that can do the hardening should we need to use a diferrent type of steel.. This my be a good question to ask PM. I'll though that out there now.
There is also a guy on Utube that has one of those new 360 degree ovens that is chomping at the bit to try it out. A good place to be able to do some prototyping before I shove this out there.
 
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