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Discussion Topic:
hub key placement
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parrish |
10-14-2010 @ 9:03 AM
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Member
Posts: 349
Joined: Oct 2009
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When I removed my passenger hub, the key fell out. Upon inspection, it has one beveled end. I figured that must be up and point toward the threads to assist hub install...To verify, I removed the driver side and don't see the bevel. Darn. So anyway, what is correct placement of the key and how far in from the threads is the key placed? Thanks for the help!
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kubes40 |
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10-14-2010 @ 1:06 PM
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Senior
Posts: 3573
Joined: Oct 2009
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If you look closely at the axle, you'll notice the key slot is cut to an even depth from the outside (near threads) to very near the inside (closest to backing plate). At a point near the inside the slot curves up and outward of the axle. The radius'd part of the key goes DOWN and to the rear.
Hope this helps. If you would like a detailed photo, let me know.
Mike "Kube" Kubarth
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parrish |
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10-14-2010 @ 2:18 PM
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Member
Posts: 349
Joined: Oct 2009
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Thanks, Mike. I'll see if I can spot the radius you mention. That makes sense with what I can observe on the still intact driver side...
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TomO |
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10-15-2010 @ 7:11 AM
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Senior
Posts: 7384
Joined: Oct 2009
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If your key fell out, make sure that the key and keyway are not worn, The key should fit snugly in the keyway.
Tom
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supereal |
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10-15-2010 @ 8:36 AM
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Senior
Posts: 6819
Joined: Oct 2009
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Amen, Tom. If the keyway is damaged, the key will likely move out of place. To tighten it, place a large hammer under the axle and peen the edges of the keyway back into place until the key fits snugly. Be sure to carefully examine the ends of the keyway for cracks. Failure to fully clean the axle taper and hub, and/or to tighten the nut as far as you can, then skipping the retightening after a hundred miles or so can damage the keyway as the hub comes loose, leading to axle breakage and loss of control.
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oldford2 |
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10-15-2010 @ 9:04 AM
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Member
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Joined: Oct 2009
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Parrish,
Take it slow. Before you start beating on the keyway with a BFH, measure the existing key with a mic. Possibly the original key is long gone and someone replaced it with a piece of ordinary keystock. Maybe someone listening will give the exact size (.0000) and hardness.
John
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supereal |
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10-16-2010 @ 10:00 AM
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Senior
Posts: 6819
Joined: Oct 2009
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The same axle key was used from '28 thru '48. It is 2 55/64" in length. I wasn't advocating whanging away on the axle with a "BFH". The big hammer is to hold the axle if the keyway shows evidence of damage, usually a ridge of metal on each side of the groove, as the edges of the keyway are peened from above. Of course, the key, itself, should be examined for signs of shearing or other misshape. The key and the key way can be measured with a good digital caliper, but the real test is a snug fit. If you suspect the key is incorrect, replace it before you address the axle. They are less than two bucks.
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Stroker |
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10-16-2010 @ 2:13 PM
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Senior
Posts: 1460
Joined: Oct 2009
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As Super say's you want a "snug fit". No one wants to lose a wheel, and I have had that happen with dire consequences. A properly fitted taper, correctly sized key and proper torque will mean that if the axle ever fails, it will do so just inboard of the keyway, and then ONLY if you dump the clutch in low with a big, "hairy" engine. Usually, you will peel the teeth off of the transmission cluster BEFORE you can twist off one of Henry's axles. The only axles I have seen fail in the keyway area were due to badly worn hubs, loose key's or improper axle torque.
It used to be that you could go to your local parts store and buy "tapered axle shims". If you had a hub that didn't want to pull-up against the taper (would bottom the threads out first), you could wrap one of the shims over the end to take up the clearance. The point I'm trying to make is that if you have a good fit between the axle and the hub, and it is tight, the key really doesn't do anything. That tapered joint is stronger than the rest of the axle.
The early "roundy-round",dry-lakes and drag racers would actually lap the hub to the axle with valve grinding compound to enhance this critical fit before they would install the key and torque the axle nut. A properly installed hub and fitted key will always require a puller to separate,
and once separated, will require a drift punch to remove the key. Any slop in this joint, any you
are essentially driving the car off the keyway, which is a recipe for having the axle fail prematurely right at the inside corner of the keyway.
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parrish |
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10-16-2010 @ 7:50 PM
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Member
Posts: 349
Joined: Oct 2009
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Ok...2 questions. I will simply buy a new key, but should the key SLIDE into the keyway lengthwise or DROP into the keyway from above? And, what is correct method of torquing the axle nut? I do own an old spring type torque wrench, but is it more of an "armstrong" approach and then again after 100 miles or so?
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40 Coupe |
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10-17-2010 @ 7:39 AM
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Senior
Posts: 1799
Joined: Oct 2009
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the correct material for the key is common square stock. This is mild steel and not hardened. Do not use "key stock" the dimension for key stock is 0.253 and the key way is 0.250 It is very surprising how many of the old keys fall out but you can run into some that are very difficult to remove. For this reason and since your at the grinder making the key grind a slight taper on the front edge where the key and the bottom of the slot meet so a small wedge can be inserted to raise the key out of the slot.
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