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DMedal

tiller shafts (again) - machinist question

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DMedal
I blew the bearings on my tiller (36") this spring and when I couldn't get the shaft off I came here for advice. It hasn't had the pin in that shaft since I bought it, just the two keys. I've spent two months soaking it in PB-Blaster (and others), have heated it glowing hot a couple of times (nice smoke!!) and have had a puller on it most of that time. I've also beat on it many many times with a 5lb hammer. After a month it moved maybe 1/16" but nothing since. Along the way the tube has bent (puller off center, I think) and the plate you bolt the tines to has quite a bow in it from the puller (no biggie) and now the plate is starting to tear loose from the shaft. This is over two months now. It ain't coming, guys. My next plan is to just cut it off and fab a new shaft. (cutting parallel to the keyways) doesn't look like a problem except for the keyways. My local machine shop doesn't have a clue how to cut the slots inside the tube. Hmmm. I walked out discouraged, then thought: would it work to cut a slot clean through the tube and weld another tube over the outside? the down side is I'm thinking this would be deeper than the original keyways. or, pray tell, is the shaft still available? rest of the tiller seems ok. -Don

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Burntime
I don't know if it is true but a guy that rebuilds pumps told me to drill it and put a grease serk in it. Apparently you can get something like 2000psi or better out of a hand held grease gun and it may blow it loose. Not sure but it would be a cheap practice run for 4 grease zerks. Good luck Don.

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DMedal
you'd have to cap the end of the tube, and the holes but that might work. 2000 psi would be less than what I'm putting on their now. My puller is a 7 ton and it is maxed out. That said, I'd try anything at this point.

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Burntime
Sorry, I had the wrong name. I dunno, may help lube it to break it free. If nothing else it will get grease in every nook and cranny and may be enough to get it sliding to break the friction. Like I said I have never tried it but it makes sense... Good luck.

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StanD
Don,t know if it will work on this but heat red hot & apply jar wax. It will draw in. May need to repeat several times. Works great on exhaust manifold bolts & nuts. Certainly worth a try. Good luck. StanD

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steve-wis
I would try heating it almost red hot, then quenching it with water. The shock might break it loose. How long is the tube that needs the keyway? And what size bore and key? There is always a way to get it done. I am a machinist, do farmer repairs alot. Show a pic or give specs, maybe can advise better. Steve

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DMedal
I wish I could post a picture of the tube off the shaft, Steve. And I'd love to know how far the tube overlaps the shaft. The best I can do is post some pics from the IPL. (not as good as UCD's, I know) I've never seen one apart and at this rate I'm not going to. These show one end of the shaft and the opposite tube, but you get the idea. There are two keyways 180 degrees apart.




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Vassal
I have the same problem with the shafts on mine, but the bearings are still ok. I gave up after the first can of PB. I think I will leave the pins out and use it that way whenever I need it, hoping maybe it will come lose on it's own some day. Please follow up if you find a way to get them free or if you have luck getting machining done. Good Luck!

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sammiefish
maybe this pic will help... you see the puller i used in the pic you also see the length of the shaft even with the long reach of the puller i had to insert a bar into the tube hole to get a better reach.... I had help with the torch while i torqued the puller it was slow going ... probably an hour each side from now on i think ill pull the tubes yearly...
[img]http://www.simpletractors.com/club2/attach/sammiefish/IMG_1358.JPG[/img]

[img]http://www.simpletractors.com/club2/attach/sammiefish/IMG_1359.JPG[/img]
If I were going to cut something I would cut the tube at the point where the keys go... the only thing you'll damage is the key.. then get back to pulling.... and replace the tube... And when you do get 'er done (and you will) if you have the config of the bearings like I did... modify so the nuts are on the outside of the case...
[img]http://www.simpletractors.com/club2/attach/sammiefish/AC%20and%20Tiller%20006.jpg[/img]

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DMedal
Thanks, Chris! This club is great for people helping people. In my case the bearing lost its balls so there's a great deal of slop, EXCEPT in the tube to shaft portion. I have no idea how many years it had no pin but those keys are sure in there solid. Your puller is exactly what I have. If you crank it down real hard you can pull the flange right off. But it isn't that much fun, so I'm not recommending it. I am sure I've got 30+ man hours on this one side, one hour would be SO easy! I was kind of figuring to cut it 90 degrees off from the keys and maybe to wind up with something that could be welded back together, maybe that's silly. Steve, this gives you a fairly good look at the parts. My shaft is already in tough shape (bent a bit, pulled one of the flanges off). I could fabricate one without too much trouble except for those key slots on the inside. My question was whether the keyways could be fabbed by having a notch cut all the way through the tube and putting a collar over the outside of the tube at that point. I'm not sure how they machined the slots on the inside but it seems to take special equipment. I realize standard keys wouldn't stay put this way but I think making a key is the least of my problems. -Don

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sammiefish
Id still say cut where the keys are, that should give you enough flex to get the tube off, do your bearing job then weld the cuts you made in the tube... :) but as you said... if your shaft is bent... (id be surprised... that shaft is big) then maybe the fab is the way to go... keep us posted!

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steve-wis
The tube can be made, but it won't be cheap in a job shop. It would take making a broach guide with a locating key opposite the broach bar to hold the two keys 180 deg. apart. The other way would be to cut the keys on a slotting attachment or a shaper. The slotting attachment is slow, as is the shaper, and most shops don't even have a shaper any more. Are the tube assemblies available yet? Might be cheaper to buy a new one. One other thought on getting it off is to get your puller pulling on the flange down close to the tube where it will be stronger. Maybe a couple of steel bars across the back side with the puller pulling on the bars? Keep us posted. Steve

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stevenj
Here's a thought on a different technique to pull the tube off the shaft. Find a bolt that will fit down the ID of the tube. Then weld a nut onto the end of the tube opposite the two keyway grooves. Thread the bolt into the nut and against the shaft. As you tighten the bolt, preferably with a large impact wrench, the tube should pull off the shaft. You might want to drop a section of round stock down the tube first so you don't mar the end of the shaft from contact with the bolt end. If the bolt doesn't pull the tube off right away, apply torque to the bolt, then strike the head with a large hammer several times. Alternate between tightening the bolt and striking the head of the bolt with the hammer and it should pull off. Once it is off, grind off the welds attaching the nut and reassemble. I'm not positive as to the relative position of the end of the shaft and the end of the tube, but you get the idea.

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Burntime
Steven, that is a great idea! The longer I own a welder the more everything looks like bar stock!:D Kinda like if a man only owns a hammer everything looks like a nail! There are some great ideas on this forum!

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Dark
Broaching tools are the only way to make Internal Keyways effectivly
quote:
http://zytools.en.alibaba.com/product/50358270-50078013/Keyway_Broach.html

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country
Depending upon how long the tube is, a machine shop with a wire EDM could also cut the keyway in a new tube. I had this problem on the Mang tiller I'm rebuilding in show and tell. The keys are the most sacraficial part, so I drilled them out knowing I'll replace them. Couldn't get the entire key out, but I was hoping it would give some relief.

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jlasater
I used StevenJ's method a couple years ago (welded large nuts on the end of the tubes and a piece of all-thread with a nut on the end) as a large puller. Worked great. Slather those keys and the shaft end with antiseize before reassembling.

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toad270
Try a different machine shop we cut internal keyways all the time either with a broach or a slotter attachment on a Bridgeport mill. The grease would work but it would have to be welded shut on the other end.

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jlasater
Found a picture from the removal operation. I left the nuts welded on afterwards. No real reason to take them off.
[img]http://images.ttyr2.com/albums/Tractors/P1010007.JPG[/img]

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M_DAngelo

Good morning All,

I used to repair Mang Jr. tillers 40 years ago for a local Taylor Rental. I convinced a friend of mine to buy one of them when they were selling them off. I now borrowed it from him and wanted to do some repairs on it. At that time, I kept track of every part number for seals and bearings for these tillers in my documentation library at Taylor Rental. Do you have the bearing and seal part numbers for any of the shafts in the Mang Jr tiller? 

Thank you,

Mike

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