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54 chevy kingpin boss help please

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54chevkiwi
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54 chevy kingpin boss help please

Post by 54chevkiwi »

Hey guys,
So i have a 54 chevy with a 4” drop axle made of 2” OD 1/4” wall DOM tube..
I had this made before becoming a machinist and having the ability to make it myself..
Its a little lacklustre, they migged the snot out of it, then got ray charles to grind the top and bottom of each boss with a flap wheel.... it aint good, a circle is more square than these things.
So, im going to cut off and redo each kingpin boss....
This leads me to a few questions if someone doesnt mind helping....

The kingpins are .867 diameter, from memory i THINK a sliding fit is .001-.0018, i dont have a .868 reamer at work but have a .8685 one so ill run that through the boss..

The boss length needs to be the opening in the spindle measurement plus the thickness of the bearing..
What clearance should i give it so the spindle and bearing fit on the boss, without needing to be shimmed and without slop..?

Since its all brand new, do i still NEED to give it enough clearance to shim the top and make it tight..? Or are shims only needed to take up the slop from in service wear over time...
Since the design uses a set screw to jam the kingpin to the back of the boss, its going to see saw on that over time and give it an hourglass shape necessitating the shimmimg...the above question refers to whether shim stock will give it a more hard wearing surface than the mild steel kinpin boss from the outset....
im probably over thinking that ..

Spindles are speedway ones already bushed and honed for the kingpins ready to install.

Thanks, i appreciate it.
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modok
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Re: 54 chevy kingpin boss help please

Post by modok »

The best way is hone the axle bore for the tightest fit possible.
Ream or bore to within maybe .002- .005" short of size and hone from there.
You can even use a slight press fit, the main thing being that the kingpin can be pressed through without scraping it up.
Should be hardened. I worked with some a few weeks ago that were dented up, but so soft I just files the dents right off. Not great.
54chevkiwi
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Re: 54 chevy kingpin boss help please

Post by 54chevkiwi »

Perfect!
Thanks for your reply
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Re: 54 chevy kingpin boss help please

Post by PackardV8 »

It's a PITA to hone axle and kingpin parts on the Sunnen Rod Shop, but that's how we do them. The real PITA is trying to measure the ID to hold the fit you want.
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54chevkiwi
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Re: 54 chevy kingpin boss help please

Post by 54chevkiwi »

Yea we have a sunnen hone at work so thats nice..

I was scoping it out today..
Itll be a ball-ache with the leverage.. but if thats how its done then thats how its done..

I think i can do most of the work on the mill, that way ill have less honing to do..
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Re: 54 chevy kingpin boss help please

Post by 54chevkiwi »

I was trying to think today how i could make it easier like, make the bosses on the lathe within a thou of the pin going, weld them on the axle then dust them with the hone to get em round again..

Welding slugs on the axle, Fixturing it in the mill and doing most of the hole work there etc..
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Re: 54 chevy kingpin boss help please

Post by modok »

A little exercise is good for you. :P
If I had to do them more often I'd like to get an adapter to use the Rod honing mandrels in the ck-10.
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Re: 54 chevy kingpin boss help please

Post by Truckedup »

I did dozens of kingpins on small and large trucks..it was typical to install a oversize pin if the axle hole got worn. Did this with an adjustable reamer turned by hand, no pilot used, axles were forged steel. The hole was reamed slightly undersized for a light press fit..
The spindle end play was shimmied for zero clearance with a very slight drag , roller element bearing on the bottom.
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
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Re: 54 chevy kingpin boss help please

Post by Ks Fats »

Trucked, here's how I do my vintage dirt stuff:
a. Hone axle for palm press fit at room temp
b. Use two 5/16-18 brass set screws on opposing sides of the king pin boss (one high, one low).
c. bearing on bottom as usual
d. Shims on top of boss to give .005
This holds up well in the grit and repeated washings these go through. On my personal car I use stacked Torrington bearings on the bottom and top of the boss but it comes apart for cleaning often( no power steering, easier to turn).
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Re: 54 chevy kingpin boss help please

Post by 54chevkiwi »

This is all good stuff!

My rear axles will arrive tomorrow, once i have that in ill pull the front axle and post pics of what the axle guy left me with, itll be better with the visual of what im dealing with.
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Re: 54 chevy kingpin boss help please

Post by 54chevkiwi »

So i pulled the axle and this is what ive got, i wrote the dimensions on the paper in the pics..
Thats the boss height and the top and bottom of each hole..
Kingpin is .867
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54chevkiwi
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Re: 54 chevy kingpin boss help please

Post by 54chevkiwi »

These are pics of the top and bottom of the bosses where ray charles got a little too saucy with a flap wheel..
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Re: 54 chevy kingpin boss help please

Post by 54chevkiwi »

The hamb had all sorts of tips on tightening the bosses from heat/weld beads ground down after to shrink it, a 304stainless insert, heating and peining the boss and re-reaming....

So far i think my best course of action is try locate a set of .015 oversize pins and ream out the both bosses to them.. im not quite comfortable with a .010 oversize pin, maybe if i could shrink the bosses first..

I need to investigate if the bushings for the oversize pins need the spindles reamed to press them in... or if the OD is the same as on the standard set just the ID is bigger..
I suspect honing .015” out of the current bushes may be too much?

As for the top and bottom of the bosses, theyre .020 too short as in i need .020 of shims in there... maybe i can tig them a little and re mill flat.. maybe with the boss reamed to the right size and thd pin tight n square there may be enough square surface there to support the bearing and shims.

All in all not as bad as what i thought i was going to face
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Re: 54 chevy kingpin boss help please

Post by Dan Timberlake »

So are you now planning to leave the axle together and NOT cut off the sorry ends and weld on new ones?

Before I finalized that re-use decision I'd dye pen or wet mag particle the welds and everything else.
Then I'd check that the bores' camber angles were acceptably satisfactorily equal on both ends, and parallel when viewed from the end.

What is the donor king pin and spindle source? '37-'48 Ford-style ? Some Chevy truck?
Some applications have oversize king pin kits from NAPA and MOOG.
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