How can I get precise measurements for my new drive shaft?

[robroy]

Good morning!

In order to ensure a "dead nuts" job on my new drive shaft (in their own words), the shop has asked me to supply them with some measurements. Here's what they're looking for:

1. The distance between the flats on the T18 yoke to the center of the mounting holes for the center bearing.
2. The distance between the center of the mounting holes for the bearing to the flats on the Dana 60 yoke.
3. The distance between the flats on the T18 yoke to the flats on the Dana 60 yoke.

The third measurement is there to serve as a check to make sure my other measurements make sense.

And by "the flats," I mean the machined surface furthest away from the splines (the surface that the U bolts [or the straps] go on to).

I began taking these measurements in my imagination with these results:

1. The tape measure I was using got all floppy and kept giving me different readings.
2. The angles between the bearing mounting holes and the yoke flats worked out so that I had to hold the measuring tape nearby and "guess" based on eyeballing it.
3. An orange hornet landed on some grease on my shirt.

I'm sure there must be an easier and more precise way to measure the distances I'm looking for. Perhaps using some modern device with a laser? Carpenters must run in to this same problem all the time.

The drive shaft guy mentioned that since the center bearing stands in a piece of rubber, there will be a little flex there which will soak up slight inaccuracies. But naturally I'd rather it be "dead nuts."

How do I get precise (within around 1/16") measurements of this distances?

Thank you!
Robroy

[bntyhntr00]

1. get a second pair of hands
if that is not possible
2. If you can physically touch each area that you need to measure between.
Get some string with no elasticity in it. tie a knot at the end of it. hold the knot onto one area and extend it to the other area mark the string at the second area and measure between the two. For the angle take the same string and attatch to the first area extend to the second and tie off taught as close to where you need it to be as possible. Hold an angle gauge up to the line and you can manipulate the string into the exact position that it needs to be to ensure an accurate measurement.

[fordman]

what is wrong with your old shaft?

[convincor]

http://www.dennysdriveshaft.com/how_to_ ... quickchart

[Happy_Camper]

I have to follow Fordman's lead here. Can the driveshaft shop duplicate the length of the stock shaft? Did you add something that would change the stock dimensions?
Otherwise two people is definitely the best way.
You know the kid who keeps trying to get you to subscribe to the newspaper, so he can go on a world tour?... time to make him a deal.

[robroy]

Hi BntyHntr00, Fordman, Scott, and Convincor, thanks for replying!

Get some string with no elasticity in it.

Perhaps an electrical extension cord?

tie a knot at the end of it. hold the knot onto one area and extend it to the other area mark the string at the second area and measure between the two.

That's a good idea!

For the angle take the same string and attatch to the first area extend to the second and tie off taught as close to where you need it to be as possible. Hold an angle gauge up to the line and you can manipulate the string into the exact position that it needs to be to ensure an accurate measurement.

It seems that I may not need to take it to that level. Perhaps because of the design of this shaft, the driveshaft guy asked for the measurement to be between the yokes and the center of the holes that the center bearing retainer mounts to. Since that will undoubtedly be a little different than the measurement from the yoke flats to the center bearing itself, I may ask the guy again when I see him in the morning.

what is wrong with your old shaft?

I initially removed it because it was so easy to access with the transmission out, and I wanted to make sure it was balanced. Then the drive shaft shop got it and told me that the center bearing had worn a groove in the shaft so serious that it wasn't repairable, and that they'd have to re-do part of the shaft to get a good bearing fit again.

Meanwhile, I heard from Dustin and others that the stock drive shaft wasn't really up to the engine I'm installing, and that I should think about having something stronger made. The drive shaft shop also had that opinion, so I went ahead with it.

The new shaft is made of steel that's about 80 thousandths thick (the factory tubing is around 50 thousandths), and the section between the center bearing and the rear end yoke is the same diameter as the front section (the factory tubing on the rear second was a lot smaller). Also, the U joints are being upgraded from 1310's to one 1330 Special (at the transmission) and two 1350s.

On top of all that, since I've installed polyurethane engine mounts made by John at AutoFab, and since the engine is different from the one it had before, it's possible that the differences could add up enough to make the stock shaft a poor fit. This way I'll know the fit is ideal.

http://www.dennysdriveshaft.com/how_to_ ... quickchart

Convincor, thank you! I'll read that in detail. I like the ready made diagrams they have for printing out and filling in. That will save me the bother of having to draw one myself and make it easier to talk to the drive shaft guy!

I have to follow Fordman's lead here. Can the driveshaft shop duplicate the length of the stock shaft? Did you add something that would change the stock dimensions?

Hey Scott! The shop could duplicate the length of the stock shaft, but in their opinion, there are too many changes going in to the truck to do that safely. The engine mounts, engine, and yokes are all different from what the factory used.

Otherwise two people is definitely the best way. You know the kid who keeps trying to get you to subscribe to the newspaper, so he can go on a world tour?... time to make him a deal.

Good idea!

Thanks again for all the great answers to my question! I'll keep ya'll updated with the method I use and how well it works.

Robroy

[thebannister8]

does the orange hornet have different powers than the green hornet

i'd use string...wrap it any ol' way to get it to run across the center of the hole and down to the other end....then mark the string with a marker..or tape... at your measuring points....then measure the string

[robroy]

Hey TheBannister8! Thanks for replying. Yes the powers are very different! I was stung a couple of times by a hornet that grew in Hugh's yard nearby my truck already. The sting made my hand swell up like a balloon!

The string method sounds doable. My only concern will be finding string that doesn't stretch at all.

Hugh (my father) also had a good idea; he suggested using a section of "all thread" threaded rod, then putting some nuts on it. Then I can hold that up under the truck and just turn the nuts until they're in the right spots to measure in between. At least with that approach I wouldn't have to worry about stretching, not to mention having it perfectly straight (since it's a metal rod)! And there's already some "all thread" somewhere in the garage.

Thanks again!
Robroy

[Alvin in AZ]

Hugh also had a good idea; he suggested using a section of "all thread"...
Robroy

While reading your first post, I though of just making it out of wood. LOL :)
Or my new better idea... :) (?)
Two wood dowels and tape them together and un-tape them and tape them together again
until you feel like it is right on the money, then measure it careful-like and write it down. :)

I picture 3/8" or 1/2" dowels with one end of one "ball shaped" to easily fit the curved surface.
Swap ends and start over on the other longer-one after having practiced up messing with the
"easier" one. ;)

One man operation.

-------------------------------------

Cool thread, Robroy, as usual! :)

I'm going to be in your shoes someday.
I want to fix up a '91 Bronco and turn it into a 2wd with a wide ratio 5 speed ZF.
...351W with a 4" stroker crank with -no- "racing mods", just a "300-I6 with 8 cylinders".
Dragged home a '90 F250 with a granny-geared ZF last Thursday. :)

Alvin in AZ