I rebuild steering columns as a part time venture. I have several
columns that someone has used the BFH method of steering wheel
removal. The end result is that the 9/16 X18 threads are destroyed.
I'm considering methods of repair. One is to turn the threads off,
bore the shaft and turn a new section from a grade 5 bolt to fit in
the bored hole, crosspin with 1/8" rollpins and attatch with loctite.
I have not been able to find another way to restore the threads,
helicoils and the like just don't seem to be used for external
threads. Do any of you have a better way to do this repair that I am
missing? Other columns use 9/16" X 27 threads and no longer have the
nuts available to suit. Would like to use the same method to convert
them over to 9/16" X18 as well. Steering columns are too rare for
these cars, MGs, to just toss the damaged ones in the trash. TIA
Why not just turn the damaged threads down, and then turn a bushing of
the proper size that will slip over the end of the shaft. Braze the
bushing on and re-thread. There was an article in Home Shop Machinist a
while back about repairing bearing surfaces this same way.
According to Gerry :
[ ... ]
Are you sure that those are even standard Unified threads?
Given that they came from MGs (you didn't say which model), they could
be Whitworth (55 degree) thread form instead of the 60 degree which is
in US threads, Unified threads, and Metric ones.
Others have already posted good suggestions for ways to deal
with your problem itself, so I won't duplicate that.
Which MGs? I have owned and driven a couple of MGAs in my time.
The original 1500, and the last 1600 MK II -- that latter one with a MGB
1800 engine in its last years.
MGs are Bs No Whitworth threads after the TF's as far as I know.
Almost everything is good old UNF except a few items like carbs and
fittings. I had thought about turning a bushing to silversolder in
place but am a bit concerned with the strength of the solder when it
gets under shear forces when the nut is tightened. Welding up stuff in
the past I have found the new metal was harder than I wanted to use a
dienut on. Can't thread it in my lathe because most columns have a bit
of a bend and would make threading accuratly mighty hard. The 9/16 X
27 seems to be a bastard thread when it comes to finding nuts to fit
Thanks for the suggestions! One of the great thing about BBS is the
vast aray of solutions that members come up with
Depending on dimensions I suspect that the simplest method would be
to face off the threaded portion of the shaft and drill and tap for a
bolt. If I remember correctly the steering wheel fits on a spline so
the threaded portion serves only to keep the wheel from being pulled.
If the threaded portion is 9/16" then installing, say, a 3/8", grade 5
or better, bolt should be sufficient. You might need to make a new
washer to retain the wheel though as a standard 3/8" washer might not
have a large enough diameter.
Bruce in Bangkok
A serious "Silver Brase" on a 1/2 inch or so of length on the sleeve is
gonna be as strong (or stronger) than your threads... That's the way I'd
FWIW I'm an old Triumph man.. Had a '68 GT6 with O-Drive that I managed to
buy a tree with.... Found a '64 SpitFire with a tosted engine-tranny..
Lifted the Spitfire body and stuck it on the GT6 Frame... Just a little
torch work to fit the traction bars in the right place and and fab some
rear shock mounts... The damn thing would eat anything in it's class alive..
.. called it the "Spit-6".. :-) Uhh.. had to put a scoop on the hood to
clear the front of the motor.. looked AWESOME.. (and yeah I couldn't us the
hood from the GT6.. uh ..it was.. uh .. scrapiron where the tree bit it...
With a joint with lots of area like a coaxial bushing on a shaft, a
good silverbraze will be considerably stronger than a couple of
transverse rollpins. Later abuse would strip new threads before
the joint fails. Use something like Handy & Harmon Easy-flow 45.
Leave about .003" clearance so the stuff can wick in. If the joint is
clean, fluxed and then slowly and evenly heated, the alloy will wick
into the joint by capillary action and completely fill the void.
I wouldn't worry too much about scrapping MGB steering collumns. Have
a look on eBay UK to see just how little these cars sell for here.
It's heartbreaking sometimes.
far as the repair, any idea around making a new end shoud be good.
Just make sure you'be got enough contact area on the soldered joint. I
would also cross pin it. That way, in the unlikely event of the joint
failing, the pin will hold just letting the wheel become loose rather
than coming completely off!
Wrong filler and/or to much admixture. I use either 6013 or a nickle
filler with a low strength rating. You've got to turn down the old
threads so they don't mix with the weld. Let the end get hot while
you weld, don't quench. Use a small diameter filler and low currents
for the first pass.
possible. I straighten the shaft. Turn down the old threads. Weld up
to diameter. Single point turn new threads. Takes a little over an
hour but I like the result. You can't tell it's a repair job.
Here's a certainly overly-complicated possibilty off the top of my
You need to repair several of these steering column threads,
There are some threads left fairly undamaged further down the shaft,
You can obtain hardenable steel, and harden it,
You have, or can make, a whitworth (or whatever) tap to match the male
Then what may be worth a try is to make a thread cutting die which can
be "split" into two halves, assembled on the undamaged threads, then
"un-screwed" to recut (chase) the damaged threads.
I haven't done this, but it seems that if at least two or three
threads were left for the split die to chase from, this may renew the
threads good enough for the nut to do its job.
As far as making a thread cutting die goes, I read about (in HSM) a
very plausible method using drill rod, soft steel plugs pressed into
the holes that form the cutting "flutes"/chip clearance on the die,
then drill (probably for more than 75% thread depth) , tap with the
soft plugs in place, and harden. After hardening , according to the
HSM article, the soft steel plugs will fall out.
Not a worthwhile method if you're only fixing a few of these steering
columns, but this reverse thread chasing method might save you from
further disfiguring the original parts.
You would probably also get stuck with making the the funky british
tap in order to make the "split die".
A farmer's implementation of this idea would be to get a nut (that
needs to be hardenable after welding):
clamp a cheap,disposable (chinese) pair of vise grips onto the nut
weld the nut onto the vise grips
heat and quench, caseharden, or otherwise harden the nut
use a 3 inch "muffler cutter" abrasive disk to split the nut (cool
often in water)
grind cutting grooves into the nut halves using dremel or??
use your nifty new thread restoring vise grips in several passes to
reverse chase the threads.
Aren't there thread restoring tools that work on this same basic
That was my initial reaction, too, but the thread has likely been well
distorted by hammering on the end. Pitch will have been destroyed,
rendering the file useless. If not, they work great in the hands of
someone that is willing to spend the necessary time to remove unwanted
On Wed, 25 Apr 2007 07:03:41 GMT, with neither quill nor qualm,
"Harold and Susan Vordos" quickly quoth:
I've sawn nuts in half and clamped them in the vise around the
threaded shaft, then unscrewed the shaft from it, before.
I have had to use my long-pistoned CP air hammer with a drift punch to
release some steering wheels before, though. Loosen the nut and use it
as a guide to hold the punch in place, then pull vigorously with one
hand and a knee, then pop the CP trigger a few times. They come right
Grind the mushroomed OD to the max thread diameter first. It works if
you don't have too much distortion. I've had to do that to remove nuts
from time to time.
Some people and their BFHs, huh?
- Metaphors Be With You -
They are no longer common but there were adjustable two piece die sets that
could be opened and placed around the shaft. It might be worthwhile to try
splitting a regular die for this purpose.
On Sun, 29 Apr 2007 21:25:19 -0500, with neither quill nor qualm, "Don
Young" quickly quoth:
Yeah, I had one of those for axle shafts eons ago before someone stole
it. It was a hinged style with a wingnut on one side to adjust
tension. I think it went from 1/2" to 1-1/2". I had only used it once
before it walked off. It was older than I was and a gift, but I
still miss it.
- Metaphors Be With You -