steering worm: pressing on shaft

F

fordman

Senior Member
1940:
I am in the process of pressing a new worm onto the steering shaft and it stopped one-quarter inch short of being fully installed. The press is hydraulic. the shaft bowed and has been straightened.

After the above problem, I put a quarter inch steel rod threaded on both ends inside the steering shaft and tightened the nuts on both ends in hopes it would pull the worm on the last one-quarter inch; it stripped the threads on the rod.

one possibility is to press the worm off and start all over with more/better grease job.

I have hesitated to torch the worm for enlarging the diameter.

suggestions?

thank you,

fordman
 
The last time I did this I used large lathe to hold the steering shaft and used the tailstock to push the worm gear into place.
 
I have done several of these recently. I heat the worm in my gas grille (BBQ) to approx 600 deg and put the end of the shaft in ice water. I bought an extra wide, two piece 3/4" shaft collar like this...

http://www.mcmaster.com/#shaft-collars/=bqk1xc

to support the shaft close to the worm. This helps to keep from bending the shaft.

I would press it off, check to make sure there are no burrs in the keyway and press on again. It's that last 1/4" that really locks it on.

Neal
 
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I have put several on by using a axle knocker nut on the threads, welding glove to hold the shaft and hitting the knocker with a hammer, like putting the handle back in a hammer. It does work, takes a little work.
 
NealinCA said:
I have done several of these recently. I heat the worm in my gas grille (BBQ) to approx 600 deg and put the end of the shaft in ice water. I bought an extra wide, two piece 3/4" shaft collar like this...

http://www.mcmaster.com/#shaft-collars/=bqk1xc

to support the shaft close to the worm. This helps to keep from bending the shaft.

I would press it off, check to make sure there are no burrs in the keyway and press on again. It's that last 1/4" that really locks it on.

Neal
Click to expand...

I think there was a thread on this forum talking about this problem. Someone said boiling the worm in oil and cooling the shaft was the trick.

I guess the BBQ grill (or the kitchen oven) or perhaps a propane torch with a broad flame could do the trick.
 
when heating stay away from flames as "carbonizing" can result, actually changes the chemical make-up of the part, I have used an electric hot plate and the heated oil with good results, press off and start over
 
The first time I tried pressing a worm gear on a steering shaft, I got the worm almost all the way on and then bowed the shaft. After doing that I began heating the worm to 500-600* F in an oven and chilling the shaft in a freezer. I also spray the end of the shaft with a dry silicon lube. I made a support tube from a section of steel pipe that had an ID that was close to the OD of the shaft and a length that would stop the worm in the correct location on the shaft. This method works well for me. Although it would be interesting to try Neal's locking collar method.
 
Just went through this. I tried the heating and cooling idea but it did not work. I also came 1/4" short. Took it to a machine shop with a 20 Ton press. Came out perfectly. Plus I had him hone the new bushings at the same time. Best $60 I ever spent.
 
John Mc said:
Just went through this. I tried the heating and cooling idea but it did not work. I also came 1/4" short. Took it to a machine shop with a 20 Ton press. Came out perfectly. Plus I had him hone the new bushings at the same time. Best $60 I ever spent.
Click to expand...

How do they hold the shaft when pressing?
 
Properly holding the steering shaft to prevent bowing and/or bending is the key to success here. Some bowing can be corrected but if you bend it, your probably finished. I'm also wondering how John Mc's machine shop held/supported the shaft. I would like to try Neal's locking collar idea but I'm wondering if a collar like that could do the job at room temp without the heating, cooling, and lube application??
 
Fordman,
I saw this process in one of Lorin Sorensens videos a long
time ago. As I recall the worm was warmed up in an induction coil,
we all have one of those of course, and slid on the shaft. The shaft
was fixtured and the sliding was done by a BIG press.
On the one I just did I used a small MAPP torch to warm up the
worm and supported the shaft in a piece of water pipe. I do admit that
I had to reheat the worm 3 times to finally get it home....I will admit too
that my 20 ton press was cryin' all the time.
When all was cooled down I carefully ran a sharp file across the
worm and miraculously it was still hard. At no time did I heat it the point
of even a straw color.
It only took about one six pack and 4 hours.
Charlie ny
 
I took a piece of aluminum plate, put it on cement floor using it as an anvil drove the shaft through the gear by hitting gear first... Let me know if you don't understand this... Worked great for me, and I've got the press... Karl
 
First off, if you have heated the parts and they show ANY color afterward, they are junk.
The collar method is the proper way to do it but the collar needs to be similar to a barrel vise used in gunsmithing to remove barrels from actions.
There are many anti-seize compounds on the market and one of these should be used.
 
final report on pressing the worm on the shaft: I took the option to go to a big "oil field machine shop" where they put it in a jumbo lathe and secured the shaft behind the keyway end. they pressed it on with the 'tail end'.

it did not go easy! very difficult to prevent the shaft from sliding.
very difficult, but it did go on.

thank you for the guidance,

fordman
 
Years ago I made some tooling from aluminum. First, took a 1" thick aluminum block and bored a 3/4" (shaft size) hole in it. This goes behind the worm gear and then use a BF Proto 2-jaw puller (secured in a vise) to pull on the block and push the shaft out of the worm. This does not stress the shaft so no problem with bowing or bending.

To install the worm, took another block of aluminum, bored a hole in it and used a die to cut threads, bored two holes for clamping bolts to pass thru, then
sawed the block in half at a right angle to the bolts, which saw cut caused the
bored/threaded hole to clamp tightly on the shaft. Then used the same BF
Proto puller (secured in a vise) to pull on the clamping block (same idea as the collar mentioned/shown by Chris) and push the worm back onto the shaft. Dressing the end of the shaft and worm ID a little to make it burr-free helps. Also use whatever lube you like to help the worm slide on smoothly. Again, no
stress on the shaft, so no problem with bowing or bending...

Note that the "previous design" Argentina-made 32-34 worms DID NOT want to go onto an original shaft correctly, were clocked incorrectly and were JUNK. The new-design 32-34 Argentina worms (and sector gears) seem to be good
in all respects, so far...

I don't post photos, but if anyone would like some, e-mail me earlyv8@aol.com

Like many things, there are different ways to accomplish this, but the important thing is to get the worm all the way onto the shaft without bending
the shaft or otherwise screwing things up. I do not like hammering on anything, especially the threaded end of the shaft; it is relatively weak and gets ruined easily. I do not like using heat because I am not smart enough to know when enough is enough or too much. Stuff in the freezer usually does not get cold enough or stay cold enough once removed. Maybe some liquid nitrogen would work??? :>) Bought my BF Proto back in 1972ish and it just keeps on working... looks like it will outlive me!!!
 
I did one by tack welding a pipe flange to the shaft and then pressing it on with a press. Took the flange off with the grinder when done.
 
Does anyone know for a True Fact how they did it on the assembly line? (with specifics such as temperatures, presses, fixtures, etc)

Not sure I agree on use of anti-seize when assembling, the whole point of the interference fit is to hold the gear without any slip or lash; it needs friction.

I also wonder if the surface finish on an old shaft is a big part of the problem?
 
Just done this job and opted for doing it cold and using plenty of force! I'm sure this is how they would have done it at the factory, they wouldn't want to have the inconvenience of a heating process on the assembly line if it could be avoided and in any case it would be so easy to ruin the heat treatment of the worm. I thought about slipping the shaft inside a heavy walled tube to prevent it bowing but in the end I TIG welded a collar on the shaft. Then it was a straightforward pressing job on a fly press, though it took quite a lot of force to seat it that last bit. Finally I turned off the collar and with some minor straightening the job was done.
 
i just did this job... pressed the worm gear off with a 20 ton press.. pressed right out...
tried heating the worm gear and installing with a hammer and sleeve... it took a long time and in the end ruined the worm gear(i had a feeling that this was not the way to execute the repair, but did it anyway). $75 later(new worm gear) and a two piece 3/4 collar , and a 20 ton press and she went on like butter on toast- no matter how much i think i know, or research i do it seems like i always have to learn the hard way!

now who knows how to remove the sector gear?????
 
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