View Full Version : How I repaired threads w/pics

Ohio Farmer
05-03-2008, 08:19 PM
Hello all:
I am relatively new to this forum and thought while I had the time today to contribute a little I would.
While planting corn a few days ago the ball joint that steers my tractor had unscrewed itself from the steer cylinder because I didn't have the check nut tight enough. In the process as the last several threads neared their end it ripped itself out as I turned a corner. I didn't have the time to spend on the lathe at that time so I purchased a new one and thought I would repair this one for a spare when I had time especially when I seen the cost of the new one...103 bucks !:eek:
This is for the folks who may not know how to do this task. This is assuming that you already know how to chase threads from scratch. I also used an aloris type tool holder but can also be done with the lantern type. I was taught from my Step-dad several years ago. He is a retired life-long machinist who has forgot more than I will ever know. The first step to repairing any damaged thread is of course to know the thread pitch and to chuck it up in the lathe. In order to do this for a balljoint I had to use a 4 jaw chuck and indicate it straight. This was a little tough to do because I was dealing with several planes. In order to use an indicator on the exposed threads I had to set the lathe to 14 tpi and engage the half nuts and then set an indicator on the crown of the threads ( good ones). By placing the headstock in neutral I was able to turn the head by hand and the indicator stayed on the crown of the threads as I turned to indicate zero. All of this wouldn't have had to be done if the piece was straight but is a good scenario for the parts that can't be chucked in a 3 jaw or where you have nothing but threads to indicate on.
Now that I have the part indicated straight and true I am ready to set up for chasing the threads. Install your typical 60 deg.cutting tool into the holder and at this time just leave it loose. Make sure your lathe is ready to cut the proper thread ( 14 tpi in this case) and go ahead and engage the half nuts.Cutter is not ready to cut at this time ! At this time we wanna take all the slack out of the machine ie: leadscrew, slop anywhere else there may be some. You can do this by turning the head by hand or slowly engaging the machine with it running. Once the slack is out go ahead and position the crossfeed ( tool) close to where it needs to be...set zero on the cross however you do it with your lathe. Compound should already be at 29 deg. Now bring the toolbit which is still loose in your holder to fit in one of the threads in the damaged part. The part is acting as your fishtail setup tool that you normally use to set up with. Of course the center hight should be set as well. With tool bit in threads lock it down now ! Disengage half nuts and back out the crossslide. You are know ready to proceed with cleaning up the threads. If you have it all setup right your lathe will follow the existing threads perfectly removing any damaged material. The threads will never be as good as they once were but usuable ! I'm not much of a writer so I hope this makes sense. If ya have questions ask away I will do my best to answer. I grabbed a few pics of the project.

Ball joint in dicated in the 4 jaw

A lousy pic of the damaged threads

Threads repaired...sorry the pics arn't very good

05-03-2008, 09:40 PM
Thanks for sharing the blow by blow fix. I will file that away.
The pics really help and the writing is fine. Good one.


05-03-2008, 09:45 PM
Nice save !

Of course now that you have a spare, that assures that you will never have need for it :D

05-03-2008, 09:47 PM
Great explanation and pictures...thanks!

I'll file that one away for whenever I actually learn to cut threads on my lathe and need to fix 'em later.;)

Mark Hockett
05-03-2008, 10:38 PM
Another way to fix that part is with a thread file. Here is a description,

BTW what kind of tractor is that off of?

05-04-2008, 03:10 AM
That was good use of a day when the fields are to wet to plant , good job and description.

05-04-2008, 03:41 AM
I'm glad to see you're not a member of the "throwaway"society.
Many people would have simply biffed it in the trash,and a perfectly usable item would have gone to waste.
Great job on the thread,and there's nothing wrong with your pics or writing either.Give that man a cigar!:D.

Ohio Farmer
05-04-2008, 09:01 AM
Ken...your right, I will never need it now that it's fixed and ready to go on the shelf, especially since I tightened the jamb nut on the new one..lol.

Dickey...you wanna learn? I'll teach ya how ..right here. Not that hard !You and many others will benefit.

Mark..The file would definatly work even in the field had I of had one. The tractor is a 2390 case. Bout a 165 hp tractor. It used to be a short wheelbase tractor and I flipped the front axle around and made it a long wheelbase looking for a smoother ride. Thats when the jam nut got left loose ! This tractor came both long and short WB. It did help the rough ride somewhat. 23 deg firestone radial tires on the rear with 12 lbs of air helped more than anything !

Mark Hockett
05-04-2008, 03:09 PM
Ohio Farmer,

I thought the tie rod end looked familiar. I have a Case 480CK that I have completely rebuilt from one end to the other. I could have bought a new tractor for what it cost me to rebuild this one but I had fun doing it. I bought the tractor with a cracked engine block so I got a new block and rebuilt the engine, new radiator, I went through the transmission and installed a new ring and pinion because of a broken gear, clutch, replaced all the brake parts, replaced every hydraulic valve and rebuilt every hydraulic cylinder, replaced both steering cylinders and rebuilt the steering control, new steering wheel, all new wheel bearings, drag link and tie rod ends, added fuel level and oil pressure gages from a 580CK, complete new wiring harness, starter and generator, new paint and decals and a bunch of other stuff.
I have owned this tractor for 8 years and had to split it three times. The last time was to replace the clutch because the pressure plate let go. I am getting fairly quick at splitting it, I had the clutch done in three and a half hours and that included turning the flywheel on my brake lathe.
I have restored two of these, the other one was a 530CK. which needed nearly as much stuff. I sold the 530 right after it was done, the guy who bought it knew the work I put into it and wanted it bad and was willing to pay for it.

Ohio Farmer
05-04-2008, 05:59 PM
Way to go on the rebuild Mark. I know what ya mean on getting speedy with the repairs...lol. I had that 2390 split in half twice after I bought it to replace the power shift clutches and then helped my brother-in-law split his 2590. He thought I was an allstar mechanic..lol. By the time we got to his tractor I think I could have done it blindfolded....Randy

05-04-2008, 08:31 PM
Thanks for a great explanation!

Have seen a triangular repair threads gizmo that I have not tested @ Home Depot (may also be available at Sears). Essentially tighten it onto the damaged threads & twist it. One size fits all. No idea of the range of threads or if it is metric & inch. ~$20 (Cdn). Simple if it works.

05-04-2008, 08:48 PM
Ahh, you mean one of these? This one came from Fastenal. It works OK to clean up minor boogered up threads but probably wouldn't fix a ripped off part like Mr. Farmer had.


05-05-2008, 05:08 PM
Great Job happy to see you came out with a good working part in the end which is always the main thing, writing and pics where great I also am new to this site and would like to see more step by step procedures and different types of setup. Although I do disagree that The threads will never be as good as they once were. With a little filler metal and proper machine settings anything can be as good as it once was, but that part has to be worth your time.