Frank Wilkie Posted October 31, 2021 Share Posted October 31, 2021 What type of steel was used to making rear-end gears for the 1934 Buick? Temper, heat treat requirement? Any info ? I'm considering making my own for a different gear ratio.. Link to comment Share on other sites More sharing options...
edinmass Posted October 31, 2021 Share Posted October 31, 2021 (edited) It’s fifty times more complicated than you can comprehend........pay an experienced shop to do the work. Yes, we have made and manufactured similar items in the past. Testing to destruction, heat treating, ........the issues are endless. Edited October 31, 2021 by edinmass (see edit history) 3 3 Link to comment Share on other sites More sharing options...
joe_padavano Posted October 31, 2021 Share Posted October 31, 2021 Start here. Link to comment Share on other sites More sharing options...
Oregon Desert model 45 Posted October 31, 2021 Share Posted October 31, 2021 Many years ago I worked at a big shop that machined bevel gears using old fashioned gear hobbing machines. Nowdays most of this equipment has gone to CNC, but If you start calling used machinery dealers its possible you might even find old manual machines that date back to the 30's or 40's. Unless you can pick up a machine at scrap metal prices with the correct cutters, you are not going to equip you own shop and produce these gears for less than the cost of having them made by a shop that specializes in machining and heat treating these gears. There are multiple videos on youtube showing both old and new machines cutting gears. 1 Link to comment Share on other sites More sharing options...
trini Posted October 31, 2021 Share Posted October 31, 2021 There are numerous machine shops that specialise in gear cutting. It is a highly skilled area. It may be better to get some one to do it. From what I know the machinist used a special steel ( soft ) enough to work but can be hardened as required for its use. The British used a system called sintered for their bicycle bearing components. Over hardening can pose a bigger problem. Most moving parts are surface hardened ( bearing ) edinmass is right. Leave it to the experts. Link to comment Share on other sites More sharing options...
1937hd45 Posted October 31, 2021 Share Posted October 31, 2021 How many people would notice a 9 inch Ford rear under there? Link to comment Share on other sites More sharing options...
Bloo Posted October 31, 2021 Share Posted October 31, 2021 Its not practical on this car. Link to comment Share on other sites More sharing options...
joe_padavano Posted October 31, 2021 Share Posted October 31, 2021 7 hours ago, Bloo said: Its not practical on this car. People have been converting torque tube drivelines to open for decades. It isn't rocket science. No, it is not a bolt in swap. Obviously if the OP wants to be optically correct, custom machined gears are the only answer. If that is not a concern, then a more modern axle and a driveline conversion are probably less expensive in the long run. Link to comment Share on other sites More sharing options...
edinmass Posted October 31, 2021 Share Posted October 31, 2021 (edited) 3 hours ago, joe_padavano said: People have been converting torque tube drivelines to open for decades. It isn't rocket science. No, it is not a bolt in swap. Obviously if the OP wants to be optically correct, custom machined gears are the only answer. If that is not a concern, then a more modern axle and a driveline conversion are probably less expensive in the long run. Why bother........if you want stock, keep it stock and make a gear set. Want a hot rod? Then build one. It's a slippery slope.........a properly sorted Buick is a great driver......toss in a gear splitter.......and its fine for 99 percent of situations. Running an early Buick too fast isn't a good idea. The bakes, suspension, and steering are not designed for 80 mph. It's why many of us own several old cars.......different cars for different applications..........trying to make ANY car do what is wasn't designed for is a bad idea. Driving it in it's sweet spot is where it is at on all pre war cars.......a high speed rear or gear splitter is fine if your only trying to bump up the sweet spot 5-7 mph. After that.......you should buy a different platform. Edited October 31, 2021 by edinmass (see edit history) 6 Link to comment Share on other sites More sharing options...
JV Puleo Posted October 31, 2021 Share Posted October 31, 2021 I tried looking this up in the SAE Handbook, but while the qualities of the various steels are distinguished, it doesn't tell us which ones were intended for each purpose. That said, the real issue here is that it is two beveled gears. With a car this late, it might even be a spiral bevel gear. Never having taken one apart, I simply don't know. In any case, these are difficult gears to cut because the tooth profile tapers inward towards the middle. The only way it can be done on a conventional horizontal mill with a dividing head requires that each tooth be hand filed to get the taper - something that is unlikely to give you the precision you'd want. They can be cut with specialized gear cutting machines. This is how they were originally made. These go back to before the automobile so they have been available for this type of work from the beginning. Brown & Sharpe made them, as did Gleason. If you could find one of those machines you'd have a fighting chance of making them but it they would still require heat treating etc... At one point I bid on a gear making machine with a huge amount of attendant tooling. I was the high bidder at $150...but the seller, wisely, withdrew it. I had thought to set this up as a side-line business - making rear end sets for antique cars and, had my bid been accepted I may have but without that specialized equipment it would not be practical. Link to comment Share on other sites More sharing options...
Bhigdog Posted October 31, 2021 Share Posted October 31, 2021 And then there is the required heat treatment or nitriding, grinding including cylindrical and all the attendant metrology equipment required. Can you do it? Whatever was once made by the hand of man can again be made by the hand of man. Should you do it? If your pockets are deep enough and you want a very challenging project, sure. Why not. BTW, A XRF hand held spectrometer can tell you the approximate alloy of steel in your old gears. You can likely find an equivalent alloy................Bob Link to comment Share on other sites More sharing options...
F&J Posted October 31, 2021 Share Posted October 31, 2021 Most people with a 1934 era car don't expect to go 80 on the highway, they just want to be able to keep up with traffic speed on a secondary State or County road without the motor screaming. Even more so now with texters on your tail. That is why I never see stock prewars driving around here anymore. That being a 34 Buick means closed drive and "maybe" there could be a slightly newer torque tube Buick rear end that would work, but now you'd be dealing with converting that newer rear end to the 34 mechanical cable operated brakes (even if you find a way to make the newer Buick closed rear end bolt up to the 34 torque tube pieces). Nothing is easy. Also, a 34 Buick transmission will have First and Reverse gear ratios "geared up" much higher to work well with the stock 1934 upper 4:00's rear end ratio, compared to the 1st/rev ratios inside a 1940s-50s transmission. So if you get a newer rear end with a ratio of 3:50 or lower number, you have to ride the clutch a lot in first or reverse to get the car to start to move. It will be too fast in reverse, too. I put a 3:80 gear in my 1932 Nash to replace the 4:73, and I can really feel that 1st and reverse are now just a bit too geared up. It's OK on flat ground to get it moving, ... a 4:10 would have been better to get it moving, but maybe that 4:10 would still be screaming the motor at 55 mph. Lots to think about when swapping ratios. Link to comment Share on other sites More sharing options...
F&J Posted October 31, 2021 Share Posted October 31, 2021 Another thing that I forgot to say about putting too much of gear ratio change in the rear end,... you end up with running out of torque and road speed on a hill that you used to be able to pull on 3rd gear, and now you are forced to shift to second gear (and you will be screaming the engine in the gutter or breakdown lane). Choose wisely on the new ratio. Link to comment Share on other sites More sharing options...
trini Posted October 31, 2021 Share Posted October 31, 2021 The engineers worked out the numbers to make the car safe for driving given the road conditions and traffic at the rime. The only thing I would recomend changing is to update the drive shaft to an open one. My 1928 Dodge Brothers has an open drive line. The diff is the size of a 5 ton truck. Link to comment Share on other sites More sharing options...
Ronnie Posted October 31, 2021 Share Posted October 31, 2021 Maybe an easy option would be to put much taller wheels and/or tires on it if they are available. That would have the same effect on the overall gear ratio to bri9ng the RPM down as changing the differential gears for a lot less money and a lot less headaches. 1 Link to comment Share on other sites More sharing options...
joe_padavano Posted October 31, 2021 Share Posted October 31, 2021 1 hour ago, Ronnie said: Maybe an easy option would be to put much taller wheels and/or tires on it if they are available. That would have the same effect on the overall gear ratio to bri9ng the RPM down as changing the differential gears for a lot less money and a lot less headaches. Depending on the Series of 1934 Buick, the stock tires are already in the 30-31 inch diameter range. You'll be hard pressed to find something taller, and the equivalent reduction in gear ratio is only the ratio of the diameters so you'd have to go a LOT taller to make an appreciable difference. Assuming you could find a 33 inch tall tire, and assuming it fits, that's only a 6.5% change in effective final drive ratio. Link to comment Share on other sites More sharing options...
Buick35 Posted October 31, 2021 Share Posted October 31, 2021 18 hours ago, Frank Wilkie said: What type of steel was used to making rear-end gears for the 1934 Buick? Temper, heat treat requirement? Any info ? I'm considering making my own for a different gear ratio.. About 15 or 20 years ago a man in Cocoa,Florida named Joe Krepps( I think he might of passed,not sure) was having gear sets made for I think 50 series Buicks for 35s.I have a 35 40 series and would be interested in different gears.It's a 4:33 now. I know you can still get an overdrive from Glen in Ohio but I'm not sure if I want to go that route. Please keep me informed how you make out. If you make a set for a 40 series let me know. Greg Link to comment Share on other sites More sharing options...
tcslr Posted November 7, 2021 Share Posted November 7, 2021 To answer the alloy question, contact a local NDE shop - and have them use their PDM ( X-ray) gun to determine what the original alloy is. It’ll give several options. Then get them to do some local hardness measurement on the existing gears. Knowing the alloy, you will cross reference that with metallurgical reference ( or better yet, contact a local engineering college that has a metallurgical department) and get suggestions on how to harden. It may be nitriding, tempering, etc. how that method is determined is you provide them the alloy and hardness field data. final hardening step will occur after final machining. I’d be surprised if AACA library has documentation on alloys and hardness. It’s always easiest to reverse from original. Link to comment Share on other sites More sharing options...
bryankazmer Posted November 7, 2021 Share Posted November 7, 2021 some scrap yards also have hand-held XRF guns - if properly calibrated they are very easy to use. clean the target area to bare metal Link to comment Share on other sites More sharing options...
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