Drive Hub

etat · December 24, 2003, 11:54:46 PM

Well, if it were mine I would weld all the way around. I've made more than a few axels, both with hollow pipe, and solid shafts. The stainless steel rods make me nervous, so does the look of the weld. Before I say anything else it would be in your best intrest to get a guard on this outfit. Might, or might not save getting seriously injured or maimed. When welding a shaft to a hub, I make the first weld with a 6011 rod, welder set on ac, then let it cool back down and grind the tacks smooth and make sure all the slag is removed. Then for strength I switch to a 7018 rod, welder set on dc. and alternate welding from one side to the other. run the bead 1'4 of the way on one side, and then 1/4 of the way on the opposing side. If it is properly tacked together it won't pull from the heat. Let it cool back down, remove all slag, and and then connect the welds, again you well be welding on opposing sides. It is better to have a professional making welds such as this. If you are worried that the heat from the welding has affected the integerity of the shaft you can go another step and retemper it. This would involve heating the WHOLE thing, up to red heat. All bearings and seals would have to be removed. Then you want it to cool back down. SLOWELY. The slower the better. The best way to accomplish this is to bury it in oil dry and let it cool down overnight. This isn't always necessary, but it is the best method. I once welded a truck axel back together after it broke, and it lasted as long as the truck. One ton truck Ford, dual wheels. -Ground the ends where it broke to a point. Tacked it together. Chipped and let it cool down naturally. Don't use water. SLOWLY, worked my way around building up the weld, chipping slag, and grinding. Once the weld was built up all the way around, and all the way through, heated and tempered, as said. Heating and cooling fast makes metal hard, but brittle. Heating and cooling slow, not near as hard, but strong. A whole different thing, but another example on tempering. You would want a knife, or an ax, to have a really hard edge that will hold that edge. But you want the body of the ax to be STRONG, and not brittle. There a number of ways to acomplish this. Here is one. The ax, or knife would have to be off the handle. Heat the ax to red hot, or non magnetic. Dip the edge of the red hot ax, use tongs, in the oil. Gonna be a lot of smoke. Do not dip more than an inch of the ax in the oil. Try to have everything arranged so you can leave it like this. Make sure your'e outside. Have a pretty good sized pan or bucket for the oil or it will catch on fire. The edge will cool fast enough so the temper will be hard. The body of the ax will cool slowly, and thus be tough. This will also work for chisels and many other tools. You want a chisel edge to be hard. But you want the part you hit with the hammer soft enough that it won't shatter when you hit it. Sorry for ramblin and getting WAY off topic.

T_in_SC · December 25, 2003, 06:04:40 AM

Hmmmmm, Thanks for the headsup guys. One reason the welds appear so ragged, other than my inexperience, is that I spot welded first on one side then the other until I got all the way around. I was thinking the size of the shaft would make up for any weakness.

Fla._Deadheader · December 25, 2003, 07:02:58 AM

I'm glad "D" and AD posted about the welding. I know they are offering experience and I was very concerned also.
There is a LOT of forces happening with the trailer wheels-tires.
Since there is not a lot of extra spacer protruding from the hub, Possibly having a longer spacer made at a machine shop as an extension, would relieve some of the stress around the original weld. Grind the weld down and install the extension from the other end of the shaft. Weld the extensions together and maybe put a hard bolt through the shaft and extension, close to the bearing, to help take the strain off the weld on the end of the shaft. A keyway would have been nice, but, I KNOW how difficult they are to cut, by hand.
Glad ya took the advice in stride. Guys here only want to see things done safely. I posted to a new member once, and he took it badly. :

SOOOOO, how does it work, overall??? Where's the BIG pictures??? ??? ;D ;D ;D

woodhaven · December 25, 2003, 07:27:44 AM

cktate,
I have used your method of tempering for years and it has always worked well for me. My question is:
Do you know a way to test for the Rockwell Hardness C scale ?
I have to take the item to the closest Tool & Die shop now. It would be nice to be able to check it here at home without a million dollar machine.

etat · December 25, 2003, 08:42:27 AM

woodhaven I do not have a home brewed test for hardness that is completely accurate per the Rockwell scale. More of an by the ear type thing. I usually do my test with a file or chisel. The harder it is, the less the file will scratch it. You can test a chisel on the side of the anvil. If it will cut into the anvil without dulling the point it is considered just about right. If a file will not cut into it at all it is harder. If you were fabricating say a die for a machine for a customer you would absolutely want to have it tested accurately, too hard and it will fail, too soft and it will fail. Sorry I can't be more help there.

etat · December 25, 2003, 01:49:23 PM

Think I ought to add when tempering some of the newer alloys don't act right. Some of these alloys are air hardening and require no quenching at all. If you do quench them they're libal to shatter. I know very little about these alloys, and when building something try to stay away from them. If welding or repairing cast iron, or many other structural metals the piece needs to be preheated before welding, and allowed to cool very, very slowly. Or it'll be prone to crack just beside the weld. A piece such as rebar, as an example, is really no good for forging, or using when building something other than using in concrete because of the varietys and types of junk metal that may be used it.

T_in_SC · December 25, 2003, 03:28:16 PM

FLA_Deadheader,

Here is the big picture. It seems to work well overall. Of course I've never run another mill so I don't have anything to compare it to. I think I will eventually upgrade from the homemade quides like you mentioned in a recent thread. I also plan to build a guard around the drive belt and add front covers and maybe back covers to the blade guard.

Fla._Deadheader · December 25, 2003, 04:20:08 PM

Looks good "T". Covers will make it very safe. What length logs, 10' ???

woodhaven · December 25, 2003, 04:31:25 PM

cktate,
I know exactly what you are saying. A lot of this imported steel is just junk. I think some of it is melted down stuff from Mars. I hate it when you spend a lot of time cutting out a part just right and then find out it won't weld or braze without a lot of encouragement.

etat · December 25, 2003, 05:19:45 PM

Wait a minute! I want to get back to the subject at hand. Specifically, I'd like to hear more details about the plans for your sawmill T_in_SC. I'd heard you could build your own using hubs and tires and such but that looks really good!

woodhaven · December 26, 2003, 02:48:49 AM

Oooop's Sorry, I was drifting away. AGAIN

dan-l-b · December 26, 2003, 05:23:32 AM

That is a good looking setup you got there T. If that was your first cant sawn, you went at it whole hog, 8) 8) Congratts

T_in_SC · December 26, 2003, 04:24:29 PM

Thanks fellas;

Fla_DH
As it stands it will cut up to 12' x 30". I may extend it later.

cktate
I bought the plans from William Rake. He has built many of these and sold plans to lot of others that have built them. The mills sold by Turner Sawmills are nearly identical. Mr. Rake is also very helpful when you email him with questions. Here is his website.
http://pennswoods.net/~zigbug/