Last night I cut down my 1938 torque tube. Installed the grease cup and put the two piece collar on the bell end of the tube. Bolted it up to the rear end and that's where I'm at. So how do I go about making a driveshaft for this thing? I am absolutely clueless and in my opinion the Bishop/Tardel book kind of glosses over this section.
I use the 32 style 4 cylinder tubular shaft and adapt the 6 spline coupler into the end. If it is a ten spline rear the coupler can be turned down and inserted directly into the tube. 6 spline are too small and need an intermediate adaptor - easily made if you have a lathe. I believe a 10 spline to 6 spline adaptor can be used, but I never had one of those. Mart.
My favorites are the '46 to '48 solid shafts. They are easy to cut to lenght. Turn the cut end to a press fit in the coupler, which is turned internally to fit on the shaft, (remove the slines in the shaft end half), and weld it solid. I've never had a balance problem or broke one. I usually use the later torque tube so I have the extra bearing but some friends have done them without the center bearing with no problems. Any competent machine shop can do the machine work to remove the slug on the end of the earlier shaft just like you were doing an open drive shaft. The toughest ones to shorten are the tapered '36 style. Have fun!
Let me see if I got this? I was going to use the 1938 drive shaft. I leave one end splined to fit in the U-joint at the transmission. I then cut down the other end and have the O.D. turned down to slip into the adapter on the rear axle and weld it solid? The torque tube is 52" long. I wasn't planning on using a center bearing. In fact I cut out that area when I shortened it. Think I'll have any problems if the drive shaft is unsupported?
The solid shaft from a model A or a 48-48 style will work. If using a model A you will cut off the tapered pinion end and use the 6 spline end to the universal. If using a later style you will cut off whatever end has the worst splines. Having said that here's how I do it. Step #1- Take the smooth non splined side of the driveshaft and clean it up really well. Avoid grinding on it as you want it to be round as possible. Sandpaper or emery work well here. Take the coupler for whatever rear end you have (6 or 10 spline) and install it on the rear. Now take your measuring device and measure from the front side how far the pinion sticks in there. Write this down! Take the coupler to a competent machine shop or friend with your driveshaft and the cleaned up end. Tell whomever is doing this you want a couple thousanths press fit. Hand them the coupler and the measurement you wrote down and have the splines turned out of the inside, it's soft steel and machines nicely. Also have them face the front of the smooth end of the coupler. Go home and re-install the coupler on the rear placing the pin in the holes, do not peen it over yet. Step#2- Install the torque tube on the banjo housing so the tube is not over the coupler. This is done by moving the left side of the torque tube to the right side of the mounting face. It'll make sense when you lat it on the floor if it doesn't now. Then take a square and measure from the face of the torque tube bell to the couplers inside at where the pinion is. You are getting an overall length from the pinion to the torque tube bell. Write this down. MEasure three times cut once is really important here. Step#3- Take your overall measurement and subtract 1/8". This is really improtant and allows a little wiggle room, all the Ford shafts I have removed all sat 1/8" inside the bell face so I go with that. Cut the driveshaft to that length. Install coupler on the pinion if for some reason you have taken it off and make sure the pin is in it to hold it for endo. Don't peen the pin yet it just is there to hold the correct length. Heat the coupler and install the driveshaft it should go in with a dead blow at this point. Install the torque tube making sure the driveshaft is inside the bell face by 1/8+/-. Step#4- Remove pinion If you can weld proficiently weld the bejeesus out of the coupler and the open pin holes on the solid shaft side, not the pinion side ( I know this is common sense, but). If you can't weld then back to the machine shop or buddies house. Make sure somebody who is competent does this. Because if it comes loose it really sucks and is alot of work to redo. Install driveshaft, peen the pin on the pinion, install torque tube, bearing, thrust washer, speedo gear and snap ring, then slide the whole mess onto the trans. Step#5- find a cold beer and relax. Good Luck, Tim Just read about the missing center bearing, never had any problems without one. You'll be just fine.
I cut the torque tube at the front and back to keep the center bearing, (that i do in house) And I have a top notch local machine shop respline my shafts. But there are many ways to do it.
I also kept the center bearing. I think it is important for vibration. i also had a local machine shop cut and respline the shaft. Everything just like Henry made it only shorter. Walter
MY machine guy thought leaving the bearing out was OK, I took out about 18 3/4", tested to 70 mph and smooth and I don't do over 50 so OK for me. Said it before, but important if you haven't noticed... There is a drain back hole for the gear lube coming through the pinion bearing to run back into the center section, a passage in the bottom of the flange allows that. Need to keep that right in relation to the speedometer turtle. As I cut out the bearing and wishbone mount, scribe a straight line through the cut out zone to match up later.
$100.00 bucks last one I had done, also tell your dad Doug from kansas city said Hi, It's been awhile since I seen him.
Thanks Doug. I will let him know you said hi. Thats a lot cheaper than the $300 cut to fit driveshafts that speedway and Dick Spadaro sell.
I always use a holesaw and cut a slight fishmouth onto the end of the coupler where its welded to the driveshaft... so your weld isn't in a circle... othewise my way is the same... bore out the splines till its a press fit on a cleaned up driveshaft... good luck Zach
I have a question for the re-splining guys. The driveshaft diameter is reduced slightly in between the splinrd areas and the bearing area. If you cut and respline, the diameter must be down a bit. Is this an issue? Or do they build it up a bit with weld first? Just curious. Mart.
Just my 2 cents after doing a few of these.The original bearing for the solid driveshafts can be a problem.They are encased in rubber and after soaking in oil for 60 or 70 years the rubber is compromised . They are real difficult to replace if you can even find a new replacement.The worn out bearing can allow the center of a solid driveshaft to "whip". I actually have a factory ford 6 spline coupler that had all the splines worn out of it from a whipping driveshaft.If you saw it you would think that someone bored out the center.Anyway,if you can find a 33/34 tubular driveshaft,you just cut off the 10 spline end(pinion end) and buy a 6/10 coupler.They are available from all the early ford places.Turn down the 10 spline end so it is a tight press fit into the tubular driveshaft( i leave it a few thousands oversize and put it in the freezer overnight. When i install it into the tube,i heat the tube a bit and drive in the frozen adapter before it heats up.Kind of like installing the pinion bearing and race in a banjo rear) Of course you have to do the math so it ends up the correct length according to your application.It should be trued up in a lathe and checked for runout before welding.If you can't do this operation any machine shop that does driveshafts should be able to.This method eliminates the whipping problem and the bearing problem and you don't need to get anything splined,which can also cause problems.Some solid driveshafts are a uniform diameter the entire length but most have a reduced diameter just after the splined section as mentioned in the above post.Also,the factory splines are cut with a rotary cutter which leaves a radiused edge in the inside corners of the grooves.If the machinist that is doing the splines does not have a rotary cutter he will use an endmill which will leave a square edge on the inside of those grooves.The square edge is much more prone to developing a stress fracture and the possibility of the spline failing.Maybe not an issue on a mild street flathead but could be a problem behind a more potent mill. the 33/34 driveshafts are not that hard to find and the adapter's are about $70.00 Hope this helps,Bob
Mitchell Overdrive people resplined a shaft for me... They set up to do it from time to time , so, if you're in the wrong part of their cycle, you have to be patient... When I did my first A-V8 drive shaft, I used a sawzall to cut the weld from a pre 1939 shaft, bought a 6 to 12 spline adapter from Mac's... Sent them to a drive line specialist... They supplied the tube... They welded. might have balanced... Under $100, cheap!! I got to measure, be carefull... Some one with post above has good plan... Karl
I wish I had taken a few pics.. Here's how I did it: I cut the shaft from the axle end by the same amount I took out of the torque tube (figured that out by mocking up the frame, f1 crossmember, firewall location etc). Then took the now short cut off piece with the axle splines and placed it splined end to the cutoff end, cradled and clamped them into angle iron to keep them straight. Tacked the ends together on the tops of the splines (not in the valley) and used a cutoff wheel to cut grooves into the plain end using the splines on the cutoff peice as a quide for spacing and depth of the 6 cuts, and then cut the tack welds. ( Figured the splines i cut into the bar end would not be perfect, but would allow me to slide the coupler back on and the rough cut splines could still add some stength) Once the cuts were made, just a few minutes for each, I slid the coupler on the newly cut "splines" and welded it solid. Then it was just a matter of putting the shaft back on the axle and setting the pin.
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