I realize this SHOULD be straightforward, but asking for anyones first-hand experience, and if there were any issues. I have a pair of finned buick drums and hubs (but I don't physically have them here yet, so I cant look at the hubs) as well as 29Rats adaptors, the game plan is to mate these with a pair of square-backs and '39/'40 backing plates and put these on the front of a O/T circa 1966 T-bucket I am gathering parts for. The thing is, I want to run vintage tork-thrust look-a-likes on it, and I am having a TOUGH time finding vintage 5 on 5" 15x6 2" bs five spokes. I'm thinking if I can re-drill them to 5 on 4 3/4" I can find wheels all day long. Anybody done this? Any comments?
Shouldn't be a problem as long as you have the equipment to do it with. You will either need a milling machine or a drill jig to drill the hubs. Then use the hubs to drill through the drums. The hubs will have to be counterbored for the heads of the studs on the back side so that they seat correctly.
You don't really need a jig, you just have to do your layout properly, and do your set-up properly when you bolt them down to the drill press table. I know how to do it, what I am more looking for is someone whos done it, if the shape of the back-side of the buick hub is going to cause any problems re: drilling an extra set of holes between the existing holes. My fault, I should have been more specific. So anyone done this? I tried to google search Buick hubs for a photo of the backside, came up empty. I guess I can just wait until I get all that stuff shipped, but if I run across a real nice pair of wheels before that happens, I'd like to feel I can pull the trigger without having problems down the road. Maybe I will just try harder to find some pics. Anybody got a pic of the backside of the Buick hub?
I redrilled my buick drums/hubs using the that simple jig rottenleonard sells. Nope, you certainly dont need one but it saved me a lot of time and i was on a mission when i built my car I went from 5x5 to 5x4.5 so i could run the 15x4 mag 5 spokes i had on my coupe. It worked perfectly and there is NO balance issues. I dont remember any issues with the stud fitment or anything like that, but i do think i may have tacked them to the hub once i pressed them in just because im strange like that. I cant 100% remember but i also vaguely remember that some of the buick hubs have a different "web" on the backside which could create an issue with the studs fitting flat. Mine didnt, but i'm thinking if they did one could chuck them up in a lathe and true the surface without compromising the integrity. Again i'd have to pull one of my wheels to get a refresher....but i know mine worked with a smaller pattern and i didnt machine anything. Incedently, i also used 29rats adapters too. Tony
Bingo, that's what I was wondering about. As far needing a jig, I'll quickly run through how you do the layout. You want your first hole to be (or pretty damn close) centered between the existing stud holes on the 5" bolt circle, 5 bolts on a 5" circle is pretty easy, so you blue the face of the spindle and scribe a 4.75 circle. Now get out your reading glasses, you are going to need them. Set your dividers to .5" and scribe an arc from the center of two bolt holes so the arcs intersect in the center. Take a ruler, lay it just off to the side of the intersection of the two arcs, and center punch a mark on the 4.75" circle you just scribed so that mark falls dead center between the two .5 arcs you just marked on the 5" bolt circle. This is the center of your first hole. Re-set your dividers to .95, and scribe another arc. Now do the same on the other side of your initial center punch mark. center punch those two marks, and repeat. You don't just keep going in the same direction, because any error will become cumulative. Now that you have your five marks punched, go back and scribe marks in the other direction if you have been careful, the arcs should all intersect the punch marks you've just made. Now you mount it on your drill press table, snug, but not tight and put a wiggler in the chuck. Align carefully so that a wiggler runs on your punch mark without wobbling. Tighten it down, double check with the wiggler, take it out, and drill your pilot hole. Then drill it to size. Repeat, until all five holes are drilled, viola. Now you just use the drilled hub as a template to drill the drum from the backside, and Bobs yer uncle. Hope you can make sense of all that, I'd draw a picture but with MY artistic skills, it probably wouldn't help.
I have had a couple rings made to make the Buick drum register on my rear axle (or front hub) and then simply slotted the 5 on 5 pattern 1/8" with a large round file toward the hub and the drum slides right on. Being center registered it can't go anywhere.
Took a couple of a pictures to help with your question. Most of the Buick hubs I have come across look like this on the inside. Could be other versions as mentioned above. There are a couple of variations in snouts as pictured. I didn't have a loose hub with the other version; so I showed both kinds with drums mounted. I know my kid has had to turn a couple down to fit the center hole in some steel wheels.
You know, when I look at this pic, the thought crosses my mind that Buick may have used the same hub casting for 4.75 bc applications, and drilled it on the other pads. Those pads where the rivets go make a guy wonder... Maybe time to cross-reference some GM bearing PN's...
I got two pair of finned drums drilled to 5 on 4.5. One pair was NOS and didn't have any holes yet and my spare used set had holes already. Here is what we ran into the lug holes on the drilled set were not concentric to the locator hole in the center of the drum (but they were concentric with the drum). We set up our rotary table of the existing lug holes. The NOS drums the locator was not concentric with the drum so we adjusted it by opening it up about .003 and indexed off of the locator hole. On yours since you are using the stock hubs you are going to need to decide how they were indexed and index them the same as original. No hill for a stepper. other then that turn and mark them to be sure that you miss all the existing holes you should be fine.
I checked, no dice, all the 4.75 bolt circle vehicles had a different bearing number. Its no big deal drilling it, just thought it would be kind of cool if I had stumbled across a bolt-in solution, of course you would still have to drill the drums anyway.
Excellent point Benno, and when I talked about the layout, I never mentioned what I would index the scribed 4.75 line from, but yes, I would want to index it off the center of the hub.
That would be deal if the setup is hub-centric. There should be enough play in the shoes to be a little off but I would be interested in knowing of the hub and the actually braking face of the drum are concentric. Maybe it is just a quirk that I have.
At some point you gotta realize too that we are dealing with "Detroit" tolerances, which are closer to carpentry than they are to a real machine shop... When the drums are turned, they are usually positioning the drum off the hub register, so theoretically, the braking surface should be at least somewhat concentric with the hub register on the drum.
don't drill yet. Take another look for some 5x5 wheels. There are usually plenty when I need a set of 5x4.75 wheels!
Yep just a quirk on my part I think. I had to straighten an S-10 frame back in the early '90s and there was not a tolerance according to the GM book that was less than +/- .125. I tried to get it closer than that because I was going to be driving it. hey you mentioned a cam shaft for 327 on another thread did you see my response? I was wondering if I was correct in my assessment of the cam shaft.
On the camshaft, yes, my pn was out of date, I since added a current pn for that cam and a link to it at Jegs. I sometimes still throw around pn's from my days as a partsman because I have them in my head, I tend to forget that was like 30 yrs ago.
.125, man that's pretty close! I remember measuring the wheelbase on a friends '67 Camaro in the seventies, it was out 5/8" from one side to the other! And that car had never been hit.
I found it on Summit 99 bucks. Cheap other then changing out to roller rockers. LOL Lift looks easy to deal with too. Do you recall the LSA on that cam? Well those 1/8s add up from one end of the car to the other. LOL it is surprising how far out of whack a chassis can be and still be drivable. We owned a '63 Impala more door that had been in a ditch once that had enough spacers in one A arm that it needed longer studs ( I have no clue where they came from). It would go down the road as straight as a string. Good drivetrain, it went into a '62 Belair post car that we found for 30 dollars. But I'll bet we drove that heap for at least a month while we were deciding what to stick the engine and tranny in.
Not all of them look like that. I have a pair that have smooth backs (un-machined). I re-drilled them myself for 5-on 4-1/2", using a drill jig from @rottenleonard, and then hit them with a piloted spot facer to make a flat for the stud shoulder to sit against. I suspect the smooth ones were later ones, as I have seen smooth ones on 90-fin drums, too.