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doctor demo
07-10-2010, 02:55 PM
Our telescopic forklift at work desperately needed the steering arm bushings replaced. Going down the road the wheels wobbled like they were on a clown car.Friday I decided it was time to make it happen.
So I pressed out the clevis pins and out of four steering arms I only found a partial bushing in one arm. I guess the factory figures that they don't need grease because there is no way to grease them.
It is a hardened pin, and a hardened steel bushing , the pin is a press fit in the clevis and the bushing is supposed to be a press fit in the arm.
After cleaning up the pins I decided they were good enough to go back in, but the arms had an oblong oversize hole.
I grabbed a piece of 3/4''scrap plate and drilled 17/32'' holes in the same pattern as the king pin retaining bolts.
Shimming the plate perpendicular to the pin bore I had a nice platform for a magnetic base drill to sit on.
http://i522.photobucket.com/albums/w348/doctordemo/th_latestPictures251.jpg (http://s522.photobucket.com/albums/w348/doctordemo/?action=view&current=latestPictures251.jpg)
I ground a 5/16'' carbide bit to use a a boring bar bit and put it in a fly cutter and then put the fly cutter in the drill.
http://i522.photobucket.com/albums/w348/doctordemo/th_latestPictures250.jpg (http://s522.photobucket.com/albums/w348/doctordemo/?action=view&current=latestPictures250.jpg)
The drill's rpm was a little fast, imo but after getting the cutter adjusted to the worst hole. The bit lasted the entire job and all four holes were within a thou.
http://i522.photobucket.com/albums/w348/doctordemo/th_latestPictures252.jpg (http://s522.photobucket.com/albums/w348/doctordemo/?action=view&current=latestPictures252.jpg)
I didn't get any pics of the bushings, the camera batteries died. It was straight forward though, I grabbed a hunk of 2''hot rolled and chucked it up in the Axleson and turned it down to 1.600''X6''long popped in a 1/2''drill and drilled to depth followed by an 1-1/8''drill. I took the piece out of the lathe and cut four pieces off in the saw to just over 1-1/4''long. Then I put them in the chi com lathe and with a boring bar, bored them to fit the pins with a 2-3 thou. clearance.I finished them to length with a facing cut on each end and tapped them into the four arms, slid the clevis links into place and pressed the pins back in.


Steve

Black_Moons
07-10-2010, 03:34 PM
Nice job. your proceedure even looks a little more professional then 'tack weld bearings, bore, smash it off with a big hammer and grind off the tacks'

motorworks
07-10-2010, 05:02 PM
Nice job.
:)

tmc_31
07-10-2010, 06:30 PM
Way to go DD,

I have one of those mag drills, a Champion, that has been a fine addition to my shop. I can see several uses for your method.

Thanks for sharing

Tim

doctor demo
07-11-2010, 02:10 PM
Thanks for the kind words. I wasn't absolutely sure that the mag base would stay put with the interrupted cut and hand feeding. I tightened up the gib screws and took it slow. An outboard bearing bolted on the bottom would have made things more rigid, but then I would have had to make a boring bar and spend more time on tooling and less time boring.

Steve

Peter.
07-11-2010, 03:14 PM
Nice work!


Are you going to add any grease-points?

doctor demo
07-11-2010, 04:41 PM
Nice work!
Are you going to add any grease-points?

Thanks.
I did consider it briefly but it seemed like more work than it would be worth.
The original bushings lasted eight years grease less, so if these last half that long I'll be happy. I'll keep an eye on the wear and if it starts getting bad I'll make some new bushings before the arms have to be re bored. If they go eight years it will be someone else's problem cause I'm shooting for retirement in seven or less.

Steve

Ian B
07-12-2010, 04:42 AM
Steve,

Nice job!

The original was hardened steel pin in hardened steel bushing. You now have a softer bushing. I can see why you didn't go the hardening route (bush size change, bore refinishing hassles etc), but would using bronze for the bushes have been an option? I ask, because I have a similar job to do on an excavator.

That remind sme, when I was living in Cairo, I bought some cast & machined bronze rod from a foundry in Alexandria. They had 2 types - "normal", and "hard". The hard stuff really is hard - unless tools are razor sharp, they just skid over the surface. The guy selling it had no idea of what was in there - does a bronze this hard sound familiar?

Wish I'd have bought a load of it...

Thanks,

Ian

japcas
07-12-2010, 08:55 AM
That remind sme, when I was living in Cairo, I bought some cast & machined bronze rod from a foundry in Alexandria. They had 2 types - "normal", and "hard". The hard stuff really is hard - unless tools are razor sharp, they just skid over the surface. The guy selling it had no idea of what was in there - does a bronze this hard sound familiar?

The hard stuff was probably an aluminum bronze, and it is hard. It does cut fair but a file just seems to want to skid over it. You can tell a big difference between it and regular bearing bronze. You really have to put some pressure on it to get a burr off. Here is a link describing the a couple of different types of bronze.
http://www.metalexpress.net/cgi-bin/index.pl?mod=catalog&ac=acDisCatList&material=Bronze&sid=0bfb0cda91d590712c5ba460ef9fa199

doctor demo
07-12-2010, 09:26 PM
Steve,
The original was hardened steel pin in hardened steel bushing. You now have a softer bushing. I can see why you didn't go the hardening route (bush size change, bore refinishing hassles etc), but would using bronze for the bushes have been an option? I ask, because I have a similar job to do on an excavator.
Ian

Bronze, Brass and even aluminum crossed My mind. It isn't a high speed or high load application and if the bushing failed completely it wouldn't be a safety issue either. What it really came down to is what piece of what material laying around the shop was the closest size to what I needed.

As far as Your excavator job, are they boom or bucket or under carriage ?
I have some hard steel bushings in two or three different sizes, how many-how big are You looking for?


Steve

ahidley
07-15-2010, 10:37 PM
Why not weld up the oval hole and bore that to original size and put in a new factory bushing?

doctor demo
07-16-2010, 01:07 AM
Why not weld up the oval hole and bore that to original size and put in a new factory bushing?
Three main reasons I didn't do that were time, available boring equipment and expense. Start to finish I had a day tied up in the project with no cost for material or a rental boring bar, if I would have welded the arms I would have had to pay for and wait for the bushings to see what size to bore to and there would be no way to bore to original specs with a mag base drill and a fly cutter.

Steve

ahidley
07-16-2010, 10:39 PM
ok, points taken