Lengthen a pto shaft

[Soundguy]

In my limited experience at welding.. it's that statement 'stronger than parent metal / breaks somewhere else/' that becomes a problem.. and if not welde dperfectly.. you see breaks right after the bead where the strength changes.

Soundguy

 

[Farmwithjunk]

In my limited experience at welding.. it's that statement 'stronger than parent metal / breaks somewhere else/' that becomes a problem.. and if not welde dperfectly.. you see breaks right after the bead where the strength changes.

Soundguy

110% correct. Also, a shipyard building carriers for the USN would no doubt have at their disposal, any and all resources, equipment, technicians, welders, and conditions to weld PERFECTLY. Average Joe, even with a reasonabley equipped home shop won't have what Newport News ship yard does.

The entire issue is spending hours using a many bucks worth of equipment to fix something that doesn't cost that much anyway. And when you're done, there's still that chance your repair is less than it should be.

 

[Slamfire]

I remember an inspector tellin' me that one weld on a hydro electric plant penstock failed inspection over 12 times. He was gettin' worried about havin' to replace the whole section of pipe.

 

[gemini5362]

ok guys as this thread goes on my memory is starting to work better. I interviewd a lot of years ago with a company that did pipe welding. They wanted someone that could work on the electronics of an automated pipe welder. Now if my memory is correct that welder was a ring with three electrodes that fit on the end of a pipe. The pipe was ground to a 45 degree angle. they fitted another pipe next to it with a 45 degree angle then the ring spun through a 120 degree circle so that the three welds made a pass all the way around the pipe. Now if i am looking at it correctly that was a butt weld. These were 80 feet of 12 inch pipe which was welded together then lowered to the ocean floor. Now if they can butt weld something together that has that kind of weight and has to sit on the ocean floor would that not work for a driveshaft ? They did not have tons of equipment and they were welding on a barge a long ways out in the ocean with all the salt spray etc.

 

[Soundguy]

Driveline injuries can and do happen often.. I imagine a cob-job patched up welded up driveline would just be an agravating factor.... That is to say.. a good condition driveline can be dangerous enough by itself ( with poor operator technique ).. the repaired / patched one just adds another variable to the list of failure modes that can happen.. thus making it a potentially more dangerous situation, vs a new driveline.. etc.

Go into a welding shop with a cracked brake drum or disc and ask for it to be welded up and turned down so you can hurry up and get back out on the highway... Or ask them to braze up a cracked brake line... See how many licensed and insured shops step up and say they will do the repair.

Some items you just don't repair.. you replace.. it's a safety issue, and a liability issue.. some more than others.. etc.

Soundguy

 

[TractorTodd]

There is something missing here. Did anyone mention SAFETY SHIELD? Does the driveline in question currently have a SAFETY SHIELD? If so will it fit the driveline after it is lengthened?

 

[gemini5362]

That is a good point about the safety shield although I am not sure what that is.

 

[Soundguy]

He is either refering to the plastic ;sheath; around the driveline.. or a mounted / flip down metal shield / shroud, covering the pto stub area on the tractor.

And let me add.. IMHO...a missing plastic sheath would be the absolute -LEAST- of my worries if i had a driveline that was scabbed and welded up... That little plastic shield will do nill when/if that driveline detonated under hi load at full rated pto rpm...

Soundguy

 

[Slamfire]

A shield only keep you from puttin' your fingers or other appendages into the driveline and havin' them ripped off. If the line broke in the middle some place it is conceivable that one part could hit the operator. Since I put an extention on the tractor's pto shaft the original shield still fits.

 

[gemini5362]

soundguy I wished I could say that english was a second language so that my ramblings could be accounted for. I try not to lie though so it is not a second language. What I was trying to say was that I get your message about why one should only use a store bought driveline versus one that had been modified at home. Hopefully that is a bit clearer.

I have given several examples of how strong welded metal can be. You have a different opinion obviously. I myself have broken a pin that holds my driveline to the power take off ( no it was not a manufactured pin it was a store bought one ) the driveline came off the brushhog I pushed in on the clutch and killed the engine nothing broke bent or becamse a missile. Your idea of a store bought driveline is a good one. I reccomend everyone to use one. I personally will use my manufactured one because I dont see it as being a danger. While we are on a safety kick here do you reccomend everyone that drives a tractor has a cab. with safety glass in the back window. The brushhog could hit something and send it flying. You might hit a yellow jacket nest while brushhoging and be killed from the stings. A huge rattle snake my strike high enough to hit your foot when you almost run over it.

 

[Soundguy]

I'm surprised that your connection at the mower did not incorporate a retainer ring to keep the yoke in place whent he pin sheared...

Soundguy

 

[gemini5362]

I dont know it is an old mower that I bought years ago that still works. The yoke fits on the shaft of the gearbox and has a spot for a pin to slide down through an aligned hole with the shaft

 

[Soundguy]

Most smooth shaft gearboxes on mowers have the shear pin hole, and then have a machined groove, or some other sort of 'keeper' to prevent the yoke from sliding off the gearbox input shaft when the shear bolt goes.

My KK mower has a c-clip in the groove... it prevents the shaft from sliding off. I've seen other methods like a bolt mounted in the end of the shaft so that the head protrudes out over one edge.. or has a large washer on it to capture the yoke.. etc.

Check yours out... This is a safety feature... Nobody wants their rotary mower drive shaft to fly off the gearbox just because the shear bolt broke...

Soundguy

 

[gemini5362]

Soundguy I will look and see before I hook up my mower again. If I dont see it I will try and take a picture to post and maybe you can tell me where it goes. I bought my mower 18 years ago and it was well used then. So I dont know how modern it is going to be concerning safety

I do however have a question and it is just an off the wall question please feel free to tell me how stupid an idea this is. Why could you not put a coil spring in the telescoping part of the driveshaft so that it pushes the ends of the driveshaft apart. That way if you had a pin to shear or something like that your driveshaft would not come off when you got it at an angle that the driveshaft would normally telescope ?

 

[Soundguy]

I guess you could.. however.. the range of motion that spring would have to run would have to be about half the length of the shaft.. my bet is you would not get enough tension on the shaft to keep it extended when it was at a 'long' length.. or if you could manage to get the tension.. then when you tried to remove the shaft.. the spring would be fighting you, making it darn near impossible to remove the pto shaft from your tractor... Besides.. no need to.. the circlip and other keeper ideas i mentioned have been used for -years-.. 18ys is plenty modern enough to have that. I used to mow with a ford 951 mower.. my neighbor bought it new in 1984.. still had the sales reciept in his manual when i went over and sharpened his blades for him... That mower is uh.. going on 23ys old.. and has the circlip feature i spoke of, same as my 7yr old KK mower.

No need to over tic the plumbing with fance springs and stuff when simple keepers using set screws, bolts and washers and c/e clips do the job just fine, and are way cheaper and easier..

Soundguy

 

[gemini5362]

Soundguy as I have been talking about in another post I am building a 4 car garage onto my house. For some reason which I dont know but am thankful for I have been blessed with beautiful december weather. It has been in the 60s and 70s with sunny weather most of the last two weeks. It rained yesterday but was sunny again today. I am making the most of the weather towards my construction work. When I get a chance I will post a picture of my mower and you can show me where that clip goes. As far as springs goes I was thinking of an old motorcycle front end that I have it has variable rate springs in the forks that would be close to the correct length