Lengthen a pto shaft

[Soundguy]

Farm.. I'm not talking about buying a new tube and welding it into a yoke.. I'm talking about taking a ..say.. 3" piece o f the tube, and welding it on to the end of the existing tube.. in order to make it a tad longer.. which it sounds like what was being sugested...

That would be like cutting an inch off a 4" bolt, and then welding it on to another 4" bolt to make a 5" bolt.. and then thinking it would be just as strong.. vs just buying the correct size bolt..

Soundguy

That shiney new factory made PTO shaft you can walk into most any farm supply store and buy was welded by SOMEONE. No reason to believe a good welder couldn't re-work an old one. Agri-Supply, Shoup, Valu-Bilt, and a host of other "mail order houses" sell the telescoping tubing stock to make those shafts.

Now.... Unless I was dead certain of my welding skills, I'd be a little gun shy of attemting this. Building your own PTO shaft obviously isn't for everyone. In the end, I doubt that it's feasable to build one cheaper than a good factory made one can be bought for.

Just because you want to know what time it is, you don't have to build your own clock.

 

[Farmwithjunk]

Farm.. I'm not talking about buying a new tube and welding it into a yoke.. I'm talking about taking a ..say.. 3" piece o f the tube, and welding it on to the end of the existing tube.. in order to make it a tad longer.. which it sounds like what was being sugested...

That would be like cutting an inch off a 4" bolt, and then welding it on to another 4" bolt to make a 5" bolt.. and then thinking it would be just as strong.. vs just buying the correct size bolt..

Soundguy

I'm not talking about scabbing a shaft together either. That's why I referred to building a new one. And I see very little sense in doing that unless the shaft is something you just can't buy pre-made. I like doing things myself when I can, but why re-invent the wheel?

 

[gemini5362]

Farm I am not trying to be obstinate and I really am asking this as a question. If you get a short piece of tubing for lets say 10.00 and you cut off the end of the driveshaft where it connects to the tractor. You put in the correct length of tubeing. and weld it all back together. That would seem to me like you were getting a working driveshaft for 10.00 versus paying 80.00 to 100.00 for a new one. If your welding skills were not as good as you think they are and the weld broke basically you would have the driveshaft come loose and spin till the implement stopped. But I have had that happen when I broke shear pin bolts that hold the driveshaft to my brush hog. Do you think doing the above would be a safety issue ? Even if the worst case scenario happened and your welds broke.

 

[Farmwithjunk]

Farm I am not trying to be obstinate and I really am asking this as a question. If you get a short piece of tubing for lets say 10.00 and you cut off the end of the driveshaft where it connects to the tractor. You put in the correct length of tubeing. and weld it all back together. That would seem to me like you were getting a working driveshaft for 10.00 versus paying 80.00 to 100.00 for a new one. If your welding skills were not as good as you think they are and the weld broke basically you would have the driveshaft come loose and spin till the implement stopped. But I have had that happen when I broke shear pin bolts that hold the driveshaft to my brush hog. Do you think doing the above would be a safety issue ? Even if the worst case scenario happened and your welds broke.

Think about it. A shearbolt shears, and the yoke spins on the input shaft.

A weld breaks in the middle of a PTO shaft and it starts flailing around right behind the operators back.

Not the same thing.

The emergency room co-pay and deductable on my insurance would eat up that $70 to $90 savings post haste. Yeah, it's a saftey issue for the most part.

And we're not even considering the down time. There's a price with that too. Band aid fixes almost always come back to haunt us.

 

[gemini5362]

I understand what you are saying. The thing that confuses me is that I have had a driveshaft come loose from the tractor when a shear bolt broke and I was going over a hill the driveshaft did do some banging around some. But I dont really think of that coming up to hit the driver. If they make the weld where the coupling goes to the tractor then if it breaks the tractor would not be driving the driveshaft and so the only rotation on the driveshaft would be while the brushhog is coasting down, which I admit will take a coulple of minutes. It also sounds like to this poster 80 to 100 dollars is a big deal. Me personally I could take an 80.00 hit with no problem. If my wife and I go out to a decent restraunt and she has wine with her meal we can spend that much. But if I was in the same predicament I would do the fix partially for the thrill of doing it myself. It seems to me like the smartest safe inexpensive way to fix it would be to get the extender someone posted. The next option might be to go to a place that makes driveshafts and point out the he does not need to have it balanced and see what they would charge to use his ends and just weld a new tube in. And please dont take offense at my questions. I know there are a lot of people on here that have forgotten more about tractors than I will ever know. It is just that from where I am reading this and I am relatively inexperienced I see a lot of posts that overwhelmingly say buy the new driveshaft. I am wondering what I am missing since I think that 1. It is not that hard a weld to do. 2. If the driveshaft broke the three point hitch on the tractor would keep it in an arc that is relatively a minor circle so it cant go flying off to the side of the brushhog.

 

[BTDT]

Something I have seen done (on trailer axles) is to sleeve the weld with a larger piece of pipe and weld it in place. That way you have 3 welds, one for the repair/splice, then slip pipe over that and weld each end. Probably not needed, but an option.

 

[Soundguy]

I'm not talking about scabbing a shaft together either. That's why I referred to building a new one. And I see very little sense in doing that unless the shaft is something you just can't buy pre-made. I like doing things myself when I can, but why re-invent the wheel?

( I thought we were on the same page.. but wasn't 100% sure.. sorry for the misunderstanding. )

Agreed. The scabbing or patching a shaft with a piece in the middle or an end is just asking for trouble in most cases. My life ain't worth 80$.. my implement probably costs sufficiently more, and doesn't need to have a welded up shaft .. break, then beat up my implement either.

Soundguy

 

[Soundguy]

Farm I am not trying to be obstinate and I really am asking this as a question. If you get a short piece of tubing for lets say 10.00 and you cut off the end of the driveshaft where it connects to the tractor. You put in the correct length of tubeing. and weld it all back together. That would seem to me like you were getting a working driveshaft for 10.00 versus paying 80.00 to 100.00 for a new one. If your welding skills were not as good as you think they are and the weld broke basically you would have the driveshaft come loose and spin till the implement stopped. But I have had that happen when I broke shear pin bolts that hold the driveshaft to my brush hog. Do you think doing the above would be a safety issue ? Even if the worst case scenario happened and your welds broke.

So what happens when that weld breaks and you have this piece of tubing spinning wildly around the back of your tractor.. beating up the lift arms, and the implement? I got some implements worth 3000$ and up.. I sure don't need a 10$ patched pto shaft beating the cr@p out of them cause i was too cheap to buy a real pto shaft.. or at least just replace the hole tube from the yoke up.. vs welding in an extension..

Soundguy

 

[Soundguy]

treusing the old yokes and just adding a new correct piece of pipe/tube is fine.. the danger comes in with the scab patch in the middle. Sure.. the loose end -propably- won't flail.. but if it does... you may be in for injury or equipment damage. it may be one of those issues where you really can't afford the initial repair.. but if it goes fubar.. you -deffinately- can't afford the repair caused by the previous failed repair.. etc.

For instance..not a long stretch here... if a failed goober'd up drive shaft took out the front double headed or tripple headed gearbox on my 10' or 15' mower.. id be almost half way into the purchase price of the 10' mower to fix it.. and I don't even want to think about the jd batwing mower repair price... I'd be sick that a cheap-skate repair cost me all that.. if the worst scenerio did happen..

Soundguy

I understand what you are saying. The thing that confuses me is that I have had a driveshaft come loose from the tractor when a shear bolt broke and I was going over a hill the driveshaft did do some banging around some. But I dont really think of that coming up to hit the driver. If they make the weld where the coupling goes to the tractor then if it breaks the tractor would not be driving the driveshaft and so the only rotation on the driveshaft would be while the brushhog is coasting down, which I admit will take a coulple of minutes. It also sounds like to this poster 80 to 100 dollars is a big deal. Me personally I could take an 80.00 hit with no problem. If my wife and I go out to a decent restraunt and she has wine with her meal we can spend that much. But if I was in the same predicament I would do the fix partially for the thrill of doing it myself. It seems to me like the smartest safe inexpensive way to fix it would be to get the extender someone posted. The next option might be to go to a place that makes driveshafts and point out the he does not need to have it balanced and see what they would charge to use his ends and just weld a new tube in. And please dont take offense at my questions. I know there are a lot of people on here that have forgotten more about tractors than I will ever know. It is just that from where I am reading this and I am relatively inexperienced I see a lot of posts that overwhelmingly say buy the new driveshaft. I am wondering what I am missing since I think that 1. It is not that hard a weld to do. 2. If the driveshaft broke the three point hitch on the tractor would keep it in an arc that is relatively a minor circle so it cant go flying off to the side of the brushhog.

 

[Farmwithjunk]

One idea that seems to be escaping all of us with the talk of piecing together a broken PTO shaft..... This is a telescoping shaft. Welding either the inside OR the outside portion would likely cause them to "not telescope". The inside shaft COULD be welded and ground to shape where it would fit inside the outer half-shaft. But it would need to be absolutely PERFECT in order to slide freely. The outside portion could be welded....on the outside...... but what happens if just a tad bit of slag finds its way to the interior of that shaft. The inner shaft wouldn't go in all the way.

And besides guys, it's more involved than just that $10 piece of metal. You have welding supplies, grinder disc's, electric for the welder and grinder, and whatever your time is worth to you. All to POSSIBLY save about $75 bucks?????

About 25 years ago, I was on a tractor pulling a silage chopper when something hung in it. The PTO shaft twisted in 2 pieces. The PTO speed was 540 RPM. My heart rate went to 1000 RPM. Trust me on this one, you DON'T want a PTO shaft snapping in two, just inches from your back.

 

[gemini5362]

Ok I understand your viewpoints. And I am sure you are very correct. I would definetly reccomend that anyone reading this thread take the advice of the other posters because they have a wealth of experience to deal from. And I will freely admit I use my tractor as a very cool play toy. I will also admit that at this point in the discussion I am probably just being obstinate. I do however just for the sake of arguement and not as a reccomendation, Think that welding in a piece of tubeing is not a lot different than taking a new tube and welding on ends. People I have talked to that know a lot about welding have told me that if you prepare it properly and get good penetration that a piece that is welded is as strong or stronger than the original. ( These guys used to weld lift hooks on steel ladles that when full weighed about 100 tons ) The few driveshafts that I have been associated with the male portion of the telescoping tube was a lot shorter than the outer female tube. If you cut the tube at one end then the chances of the male part getting to a point where it would not slide should be fairly slender. But let me reemphasize that I agree with the other posters totally and 80.00 is not much to be safe. I am just making conversational arguements here.

 

[Soundguy]

Hmm.. Most driveshafts I see that telescope are equal lengths...both sides.

With a piece of tube welde dinto the yoke.. you have 1 failure area. With a piece welded int he middle, you have 3 failure areas. And while the weld itself may well be stronger than the parent metal.. Ill wager that when you put the hp and shok to it, the place it breaks will be just past the weld where the 'weaker' metal meets the stronger metal.

If you are patching a driveline.. do a whole side... the scab is just a nightmare waiting to happen in all but the most sever situations, or in extreme emergencies.. etc.

Soundguy

 

[Farmwithjunk]

Ok I understand your viewpoints. And I am sure you are very correct. I would definetly reccomend that anyone reading this thread take the advice of the other posters because they have a wealth of experience to deal from. And I will freely admit I use my tractor as a very cool play toy. I will also admit that at this point in the discussion I am probably just being obstinate. I do however just for the sake of arguement and not as a reccomendation, Think that welding in a piece of tubeing is not a lot different than taking a new tube and welding on ends. People I have talked to that know a lot about welding have told me that if you prepare it properly and get good penetration that a piece that is welded is as strong or stronger than the original. ( These guys used to weld lift hooks on steel ladles that when full weighed about 100 tons ) The few driveshafts that I have been associated with the male portion of the telescoping tube was a lot shorter than the outer female tube. If you cut the tube at one end then the chances of the male part getting to a point where it would not slide should be fairly slender. But let me reemphasize that I agree with the other posters totally and 80.00 is not much to be safe. I am just making conversational arguements here.

When it comes to being obstinate, I take a back seat to no one. I guess my pont is this. If you have all the equipment to do the job RIGHT, and have the ability to do it RIGHT, and STILL want to take the time, you can take a wild chance on a patched pto shaft ....or....spend maybe $100. You don't have the equipment and/or ability, you can spend a bunch to have a welding shop take a crack at it. Did I mention $100 already?

Not worth the hassle. Not worth the risk.

 

[Fredex]

I do however just for the sake of arguement and not as a reccomendation, Think that welding in a piece of tubeing is not a lot different than taking a new tube and welding on ends.

Hi again, Gemini. For the sake of further description and understanding. Replacing the tube at the yoke is not quite the same as extending the existing tube. When the old tube is extended you butt-weld 2 pieces of tubing together. That's a rather thin weld. If the inner portion of the drive shaft doesn't extend past the weld into the old section, then that thin weld must transmit the entire torque load. At the yoke the tube is inserted a short distance into a square hole in the yoke. When you replace the entire section at the yoke you cut the angle-weld at the yoke and pull out the entire old section including that short section inside the yoke. Then slide in the new, longer section and re-weld to the yoke. Most of the torque is transmitted through the square tube fitted into the square hole of the yoke; the weld mostly just holds it in place.
Fred

 

[bx23barry]

All I can say is I have welded up driveshafts with 2-3 batterys, jumper cables, some stick rods and a few pairs of sunglasses in the middle of nowhere on jeeps and never had one come apart before it got home. Having it out on the bench in the shop is a piece of cake.

 

[Slamfire]

Got an extension, and it works pretty good, although there's a bit of slack in the overrunnin' clutch and that's magnified at the end of the extension. I was thinkin' of weldin' somethin' on the end of the shaft where it connects to the gearbox. Say a piece of barstock between the universal and the gearbox. What do you think. Oh the telescopin' shaft is triangular in shape there's no way to lengthen that!

 

[gemini5362]

Hi again, Gemini. For the sake of further description and understanding. Replacing the tube at the yoke is not quite the same as extending the existing tube. When the old tube is extended you butt-weld 2 pieces of tubing together. That's a rather thin weld. If the inner portion of the drive shaft doesn't extend past the weld into the old section, then that thin weld must transmit the entire torque load. At the yoke the tube is inserted a short distance into a square hole in the yoke. When you replace the entire section at the yoke you cut the angle-weld at the yoke and pull out the entire old section including that short section inside the yoke. Then slide in the new, longer section and re-weld to the yoke. Most of the torque is transmitted through the square tube fitted into the square hole of the yoke; the weld mostly just holds it in place.
Fred

Oh my god you are talking about putting a tube on the right way. I am not use to people doing that. I was talking about just cutting the tube off of the yoke then butt welding it to the tube. If you are talking about doing it right I would have to agree that would be much stronger.

once again just for the sake of arguement since I dont want to sit in the back. If you take the time to grind all the ends at a 45degree angle. then weld them up using multiple passes if necessary to the point where the weld is flush with the rest of the tube. And if you have someone that knows how to weld and get good penetration etc. I think you will break the u- joint long before you break that weld. I know fredex knows what he is talking about. I have as I posted before seen guys butt weld stuff onto various metal objects at the steel mill I worked on and let me tell you they ground it down to a 45 degree angle and then filled back in and for strength ran other beads over that. this stuff held things in the tons or 100 plus tons. I never saw a weld fail.

I had to weld a new piece in a driveshaft for my 3 ph post hole digger. I did it the way I described unfortuneatly I did not get a thick enough piece of tubing and I bent the tubeing but the weld did not break.

 

[gemini5362]

Slamfire is the slack going to really make a difference once you get the blade spinning it will keep on spinning it will it not ?

 

[Slamfire]

I hope not, it's just a little wobbly, maybe it'll be ok.

 

[gemini5362]

Every once in a while in an effort to improve myself I watch discovery channel. I just saw an episode called SUPER TOOLS it was about the specialty tools Newport News shipyard uses to build a nuclear aircraft carrier.
One of the things i noticed was that they mentioned when the shipyard puts a ship together it BUTT welds the plates together they interviewed the safety inspector the inspects welds. He said that when something was properly BUTT welded then the weld became stronger than the metal and if something was going to break it would break somewhere other than the weld.

If it is good enough to put Nuclear Aircraft Carriers together then BUTT welds should be able to hold my PTO driveshaft for my mower.