Rear axle steel type

[Factory Dog 44]

     I am looking into having a couple new rear axles machined for my 18 Automatic, and was wondering if anyone might have some insight into the correct grade of steel to use?  I am considering using 1045 medium carbon steel that has been turned, ground, and polished. 

["D"- Man 827]

I am in the process of having the same made for my 18 also, however; I am needing these longer than stock for the purpose of duals.  I know that Peerless made all the rear axles for the Sundstrand transaxles.  I assume it will likely depend on what application you are intending to use them in, and what if any attachments you will be equipping you tractor with. I have been told that Wheel Horse made an upgrade kit {for the latter D-200's that were to be used with a back hoe attachment} these axles were made of stronger metal.  I have not researched or confirmed this.  Personally I think if you are just having axles machined to replace a broken pair with like, and just using it as a riding mower you should be O.K. but, I would consider a higher grade anywhere from 1050, 4140 or top-end 4340.    These become increasingly more expensive as you go higher in grade.  Then after machining you may want to have them heat treated.  

[daveoman1966 3,762]

Knowing the man-hours involved in replacing the axles on the D series, I'd spare no expense in using the highest grade steel possible.  In the transmission reassembly process, I'd also replace ALL of the axle bearings and seals with top-end American-made brand names.       

[Factory Dog 44]

     Thanks for the input gentlemen!!  I will have to do some research on the 4140 and 4340 steels since I am not familiar with them.  It appears you are both in agreement that it would be wise going with the best material and parts possible.  I was originally going to replace all the bearings, but changed my mind when I picked up the set Toro still offered.  They looked like junk compared to what was already in it.  I will reconsider that now and do some more looking around for better bearings!  Do you have any recommendations as to who makes the best bearings?  If I could, I would also take the old shaft in to the metallurgy lab to find out what grade of steel it is made from and if or how it was heat treated.  Thanks again, and have a great weekend!!!

[pacer 3,174]

Agree on the 41xx series of steel. I have not seen any indication that the original axles were hardened - they seem to file easily, in fact I wonder if they were any more than common steel. But, as mentioned, if you are to add increased load then it may be wise to go for strength. Should be easy enough to google up the 41xx steels and familiarize your self with them.

[smoreau 658]

I know they are very hard! They make a key cutter sing cutting a new key way!

[tarcoleo 119]

Just a simpleton's suggestion; why not machine new WH axles from scrap

auto axles obtainable for cheap from junk yards? It might be necessary to

do some annealing and heat treating, but al least you know you're starting

out with steel made for the job.

 

Tom in RI

Edited February 28, 2015 by tarcoleo

[wheel-mule 46]

I am a machinist by trade.I make all my axle out of 4140 pre hard  turn ground and polished.I have never broken one that I've made for any of my pulling tractors.It it expensive but worth it.I think the last I bought was a little over a dollar an inch for 1" dia. I did make an axle one for a simplicity puller out of Stanless Steel I don't remember the alloy but I had over $250 in the material.It was 2 1/2 dia.

[Factory Dog 44]

Thanks Chuck,

 

     I was able to do a little research on some of the various alloy steel mentioned earlier in the post and concluded that any of the metals mentioned earlier, except 1018, is probably equal or greater than what was originally used on my 18 Automatic.  However, as mentioned in 23 Automatic's post, the characteristics of 4140 and 4340 steel makes them a better choice for this particular application.  I plan on using the 4140 steel because of its availability and the supplier I am looking at provides exactly what you had recommended, pre-hardened, TG&P.  I think I spent over 3 hours last night looking at web sights and thumbing through various metalworking and metallurgy books trying to figure out what would be the best steel to use.  But that is part of the fun!

    As for the bearings, I may have to eat crow.  I went onto Motion Industries web page and did a little reading on the various types of needle bearings and the verdict is still out on this matter.  I have some more research to do.  I would prefer to replace all the bearings just because that is how I am, but I won't replace them with a lower quality set.  Again, I want to thank everyone for your input, it has been really helpful!!!

[mey030 9]

Just two cents worth. My father was a dealer from 62-75 on the d series when you installed a three point for rear mower, tiller, backhoe you pulled the hubs, seals and drove in a composit sleeve type bushing and then reassembled seals and hubs. In fact I saw the install tool in my shop a week or so ago.

["D"- Man 827]

Factory, did you have any progress report on the 18 Automatic axles that you need to have machined?

[Factory Dog 44]

     Thanks for asking, but I have not made very much progress yet.  With the weather warming up a bit, I have had several other outside projects pop up that has taken precedence over my girl.  I have been stopping after work a couple nights a week to apprentice with my machinist friend who is going to show me how to spline the shafts.  He has also been very busy fabricating a 1920 something Harley Davidson out of nothing more than an engine and a transmission from some other vintage year.  Almost all the parts have been fabricated in his shop.  It has been fun watching it grow each week.  Our plan is for me to order the shafts this week, and we will cut them the week after next.  I will give an update when we get them done.  I have been able to locate all the bearings except the one 8049.  My brother-in-law is stopping at Motion Industries tomorrow to order the others and see what they can find for the 8049.  The 1526 1-1/8" axle bearings I ordered through Toro were caged needle bearings, while the ones in my transaxle were full complement.  Does anyone know why wheel horse switched to the more expensive caged bearings?  That is all I have for now, thanks again for everyone's input!!!

[Factory Dog 44]

     Just thought I would give an update.  I have gotten the 4140 steel bar stock in for the axles, but have not made any progress on getting them machined yet.  We do not have the correct cutter on hand so I will need to order one.  Determining what I need may be the hardest step.  I have been doing a lot of studying of splines and gears on the internet and have come to the conclusion that machinists are much more educated than myself.  Learning is very interesting in that the more I learn, the more I realize how little I actually know.  I would just ask my trainer, but he was busy and then I got sick for a couple of weeks.  Anyway, I came up with a pitch diameter of 1.0625" which would give me a diametrical pitch of 16.  Since there are 17 splines I think the tool # would be a 6.  I also believe they are involute splines, but am not 100% certain of this either.  I have not had any success at determining the pressure angle, even after several hours of reading articles and blogs.  I am off this week and hopefully can get moving again on this project.  Any insight or corrections are more than welcome.  Thanks!