I haven't heard of anyone actually doing this, but I have a number of rear axles that are plenty good except the keyway is worn. I am thinking about cutting a new keyway on the other side of the taper. My guess is the reduced strength from taking away stock at the taper shouldn't be a problem, but as I say, I've never heard anyone try this. Anyone have some input?
Just thinking...Why not weld up the old key way then recut it. I weld up all kinds of parts and rework them.
Richard, at least one keyway on a rear axle shaft in my grandfather's 27 coupe was worn when my father and I restored it back in the sixties. We had a local machinist do exactly what you described. That was about 45 years ago and its still going without failure. Of course the engine is stock and I don't do any 'burn outs'.
PS, I would be afraid of heat from welding, affecting the metal unless tempered or cooled correctly.
Yeah, I think Fred's got the right idea. The thing your going to want to be aware of is to be sure to use the correct wire or rod when you weld it and be aware of the changes in micro-structure that occur when you apply heat to metal. Properly done the axles could be as strong as when new. Good luck.
Geez Terry, you beat me to the punch.
What about machining the keyway oversized and using a stepped key? Just wondering. Dave
If the key way is wallowed out the taper is also worn.
All good ideas. I hadn't considered stepped keys, I may give them a try. I see Mc Master-Carr carries them. I may try it out on a junk axle first to see how it goes. Certainly sounds like a great way to save a bunch of axles I have laying around.
Lets see 100 year old metallurgy hardened by wear and stress. Now you want to either remove more metal 180 degrees apart, or weld up the offending key way and then machine it to fit the key?
For the cost of new axles, why not do the safe and right thing and just replace them. The time and cost to effect at best minimal repair will far be outdistanced by the cost of new axles.
Lets look down the road after your welded and machined axle breaks and the damage caused by your rear axle housing as it grinds along the pavement, not to mention the damage the wheel will cause to your fender and body work.
This type of repair is marginal at best not to mention the wear of the taper and the condition of the 100 year old threads.
Be safe not sorry new axles period.
Everyone has different ideas re old parts. Some will replace everything they can with the new, thinking new is better. Some will replace nothing at all and use what's there, worn or not, keeping everything original. For me, its not the $, I can certainly afford new axles, but I enjoy tinkering with original parts and salvaging them best I can. Of course safety is an issue, but I don't believe using a stepped key will weaken the axle in any meaningful way. See above post from Terry.
I am surprised at your remarks, Brass car guy. Aren't you the one who collects unrestored cars and advertised for old parts to add to your purchases?
Back in the sixties, everyone used original axles in rear ends. The only axles I ever heard fail were repops made a few years ago.
I agree, new axles are the best solution, but in the 60's, when I needed new axles for the coupe, as I remember, they weren't available. In the 70's when I needed a pair for a 13 wide track touring, I'm positive they weren't available.
I would absolutely not use an axle with a second keyway.
On a 1915 Buick, where new axles, or even good used ones, are less of an option, I have widened the keyways and used stepped keys, as others have suggested. I would however suggest that you only widen the keyway as much as is needed to true it up. I would then take the purchased stepped key and narrow it to suit the recut keyway. The idea being to remove as little stock as possible from the axle.
Richard, you are quite correct, back in the 60's which was some 50 years ago, now add that to the nearly 50 years from your build date and you get approx. 100 year old metal with antiquated metallurgy, not to mention antiquated hyatt bearings.
Now the problem I have with the old axles is the hyatt axle bearing running directly on the shaft. This causes the metal to brinell and get brittle and that is usually where the axle begins to fracture. If memory serves me correctly the model t axles break just at the outer end of the hyatt bearing.
As I do own original unrestored cars I take precautions. I have axles industrial xrayed including spindles. While getting my 1909 Stoddard Dayton up and running I had the spindles xrayed and found the spindle shaft christalized nearly 3/4th thru, just waiting for me to hit a pot hole or curb at speed and break the spindle off dropping the car down and crushing the aluminum pan at the very least. If the metal shows any sign of fatigue we make new parts as we did making both new spindles for the Stoddard
I always error on the side of caution, having been collecting and driving brass era cars for nearly 60 years, I have either expierenced or seen most every sort of mechanical issue possible and try to avoid as many as possible
There's a time to keep it original and a time to make it safe and reliable, I take safe and reliable every time. My life my family and my cars are near and dear to me. When we tour I prefer to drive back rather than on the trouble trailer.
I don't see a problem with a stepped keyway at all. The keyways in the axles that need attention are already buggered up at the keyway and have run that way, no doubt, for years without breaking. Truing up a buggered keyway to accept a tiny bit larger key at the axle will require removal of so little stock, its just not realistic to think that the process will weaken the axle any further. Now if anyone is concerned about brittleness, etc, then I suggest never use an old axle. They are all close to 100 years old and all suffer the ills some are warning against. I have to be honest, some of this sounds like Chicken Little to me. The only posts here where someone has actually tried what I suggest is Terry's and Jerry's and their experience is positive.
Would a set screw on top of the new key help? It could be under the hub cap and no one but you would ever know.Bud.
I don't follow you Ken, please explain.
Richard, if the keyway is damaged what do you think the taper is going to be like? The keyway is spread open because the car was driven with the hub loose on the axle and so the taper is going to be worn too.
Well that's a good point, Stephen. However, I can't agree that in all cases the taper would be worn unusable. I suppose one could check it out by bluing the axle and checking the fit in a hub known to be good. One thing that I do when checking the axles for wear is to see if the taper is bent. In many cases they are and that's the end of the story for me.
The other question that comes to my mind from reading your post is what extent wear on the taper is of practical importance. A better way of asking the question is how much wear is tolerated before the axle/wheel fit becomes an issue. I don't know the answer to that, do you?
To take the risk of running the original axles is an individual choice. I suggest careful inspection of the bearing diameters to assure minimal wear. I would also suspect the taper on any axles that have a wallowed out key way. Checking the form could be done as a functional check using a known good taper and possibly looking at the profile in a 30" optical comparator or at least setting it up on a sine bar. There's no way to inspect for embrittlement with the use of some type nondestructive testing. Given an opportunity I'd find somebody that could perform magnetic particle inspection to look for stringers, checking or cracks. You're still not going to be able to look at microstructure without destroying the part. So in the final analysis it comes down to choice. There are a lot of 100 year old axles out there still holding up quite well. But they're very capable of breaking and causing a lot of expense. Now would anyone be interested in discussing spindles. Personally, I'm running used axles on my '22 because they showed very minimal wear on the bearing surfaces. Then on the Sedan I turned around and bought new axles.
An easy way to check for excessive taper is to mount a hub, either wood or wire on the axle. If the brake drum hits the brake shoe and extends excessively past the backing plate; you can bet the taper is worn excessively.
Shims are made to compensate for worn taper. If the taper in the hub is wallowed out slightly so the hub doesn't fit right to the axle, then it can be ground to fit much better with some valve grinding paste and elbow grease.
Older post with some info on taper dimensions.
For me, fitting a new axle in rebuilding the rear end is std. practice. IMHO replace the old axle with a new one, inexpensive in the overall redo of the rear end restored to good specs.
Ford axles removed by me always have one or more problems, usually too much wear at the bearing surfaces, busted, or mushroomed threads at the axle nut, and worn down keyways always come with axle tapers that are shot.
The important thing to inspect for with a spread keyway is the possibility of cracks. I have seen several axles that have developed cracks radiating out from the corners of the keyway, at the large end of the taper. These axles are not rebuildable by any means.
To respond to other's concerns about worn tapers. Yes, a spread keyway is probably also associated with wear in the taper. The taper will also be distorted adjacent to the spread keyway. It's just a matter of judging the degree of wear and the need to dress down any raised material adjacent to the taper. Obviously, not every axle would be rebuildable by this method, just in cases where all other factors are acceptable.
even a new axle should be lapped in for a better fit. charley