[MoonBat]

I'm building a '31 Ford hot rod (see Sluggo the '31 Ford in projects / builds). I am using a short section of 3/4-36 spline shaft to connect the rack & pinion steering to the steering shaft (Borgeson 3/4xDD). The U-joint I bought is 3/4-36 on one end and 3/4 DD on the other. The splined end fits- the DD end just wont. Did I buy a cheap joint (it was almost $30.00) or does it just need a little "persuasion" (e.g. hammer or bench grinder) ? There surely can't be two kinds of DD shaft.
Thanks in advance,
Buzz (MoonBat)

 

[johnsongrass1]

Might be off size.
Is the shaft .750 DOM? If not DOM, some hand work will be needed to make it fit. File, flap disk, emery, die grinder, burr, whatever you got.
$30 is cheap....you can still make it work with hand fitting. Welding the shaft and joint together is your best best once it gets fitted.

 

[MoonBat]

Might be off size.
Is the shaft .750 DOM? If not DOM, some hand work will be needed to make it fit. File, flap disk, emery, die grinder, burr, whatever you got.
$30 is cheap....you can still make it work with hand fitting. Welding the shaft and joint together is your best best once it gets fitted.

Johnson,
I'm not familiar with the DOM term. Can you give me a little more info ? I appreciate your response. I was being sarcastic when I said that there couldn't possiblt be TWO double D's. Who knew ?
Buzz (MoonBat)

 

[johnsongrass1]

DOM....Drawn over Mandrel tubing like that used in chassis fabrication for example. It's has a consistent ID and OD. all the steering joint's I've messed with assume sizing based on the tubing being exactly .750od.
Pipe OD is ID nominal so if it were used and not DOM tubing, you may have to hand fit by sanding the OD to fit.
Sarcasm......I need a sarcasm button on this keyboard.
I suppose it's possible the DD flats are very parallel.

 

[MoonBat]

DOM....Drawn over Mandrel tubing like that used in chassis fabrication for example. It's has a consistent ID and OD. all the steering joint's I've messed with assume sizing based on the tubing being exactly .750od.
Pipe OD is ID nominal so if it were used and not DOM tubing, you may have to hand fit by sanding the OD to fit.
Sarcasm......I need a sarcasm button on this keyboard.
I suppose it's possible the DD flats are very parallel.

Thanks,
Buzz

 

[39 master]

The quality U-joints run anywhere from $85 to $115. The double D shaft is either steel or stainless and both are solid. You should need at least two U-joints, one at the rack and the other at the steering column. I say at least two if you are lucky enough to clear the exhaust (which is usually not the case). When three are required a Heims joint is required to support the shaft somewhere in the middle. The cheaper U-joints have bushing where the others have needle bearings and will last much longer and are more robust for street use. Be sure to clock them correctly and no more than 30 degrees.

 

[MoonBat]

The quality U-joints run anywhere from $85 to $115. The double D shaft is either steel or stainless and both are solid. You should need at least two U-joints, one at the rack and the other at the steering column. I say at least two if you are lucky enough to clear the exhaust (which is usually not the case). When three are required a Heims joint is required to support the shaft somewhere in the middle. The cheaper U-joints have bushing where the others have needle bearings and will last much longer and are more robust for street use. Be sure to clock them correctly and no more than 30 degrees.

Thanks,
Buzz

 

[cerial]

Throw the u joint in your freezer overnight, heat up the shaft, pull the u joint out of the fridge and press it in by hand(with gloves on) being careful not to drop/angle any needles. If it will not go in you have the wrong size.

 

[MoonBat]

Throw the u joint in your freezer overnight, heat up the shaft, pull the u joint out of the fridge and press it in by hand(with gloves on) being careful not to drop/angle any needles. If it will not go in you have the wrong size.

Cerial,
Thanks for the comment. Since the shaft is too large for the U-joint, II think I'll try heating the joint and cooling the shaft instead. Interesting idea,
Buzz

 

[57Nomad]

Measure with a verniers, across the inside flats and over the shaft flats. There is generally .0005” to .001” difference. The resulting clearance allows fit. But if the shaft is bigger you need to file both sides of flats fairly evenly to allow tight fit. Also the shaft measured s/b .0005”/.001” smaller than the round portion of the hole. Sand down shaft chucked in drill with sand paper to also allow a tight fit. If too long for drill a wiz wheel going round and round shaft will do the same but take a bit longer. Generally only one feature (round or flats) causes interference, not both.

Generally the difference is only a .001” or so. Mill stock is quality controlled fairly tight.

 

[MoonBat]

Cerial,
Thanks for the comment. Since the shaft is too large for the U-joint, II think I'll try heating the joint and cooling the shaft instead. Interesting idea,
Buzz

Measure with a verniers, across the inside flats and over the shaft flats. There is generally .0005” to .001” difference. The resulting clearance allows fit. But if the shaft is bigger you need to file both sides of flats fairly evenly to allow tight fit. Also the shaft measured s/b .0005”/.001” smaller than the round portion of the hole. Sand down shaft chucked in drill with sand paper to also allow a tight fit. If too long for drill a wiz wheel going round and round shaft will do the same but take a bit longer. Generally only one feature (round or flats) causes interference, not both.

Generally the difference is only a .001” or so. Mill stock is quality controlled fairly tight.

Nomad,
Thanks for your comment. I've ordered a steel (no plating) U-joint to see if that makes a difference. If I can avoid grinding/ / filing I will sleep better. BTW I love your car. My after-school job in HS was delivering prescriptions for a pharmacist who let me drive his Nomad. My classmates were green with envy. I think he just didn't want to have his scrips delivered by my scroungy '31 Ford hot rod.
Best wishes,
Buzz

 

[enjenjo]

There surely can't be two kinds of DD shaft

Actually there can be. It may be a metric U joint and an Imperial shaft. 19mm vs .750" there is about .05mm difference.

 

[MoonBat]

Measure with a verniers, across the inside flats and over the shaft flats. There is generally .0005” to .001” difference. The resulting clearance allows fit. But if the shaft is bigger you need to file both sides of flats fairly evenly to allow tight fit. Also the shaft measured s/b .0005”/.001” smaller than the round portion of the hole. Sand down shaft chucked in drill with sand paper to also allow a tight fit. If too long for drill a wiz wheel going round and round shaft will do the same but take a bit longer. Generally only one feature (round or flats) causes interference, not both.

Generally the difference is only a .001” or so. Mill stock is quality controlled fairly tight.

Thanks for nyour help.
Buzz

 

[MoonBat]

DOM....Drawn over Mandrel tubing like that used in chassis fabrication for example. It's has a consistent ID and OD. all the steering joint's I've messed with assume sizing based on the tubing being exactly .750od.
Pipe OD is ID nominal so if it were used and not DOM tubing, you may have to hand fit by sanding the OD to fit.
Sarcasm......I need a sarcasm button on this keyboard.
I suppose it's possible the DD flats are very parallel.

Thanks for your help.
Buzz

 

[MoonBat]

Thanks everybody. I just got off the phone. I finally reached someone at Borgeson. I gave him the full sad story. He told me that the "inexpensive" ($30 or so )U-joints are from off-shore countries that have different specs. He assured me that (USA made) Borgeson needle-bearing U-joints will fit my Borgeson 3/4 DD shaft. I have ordered two stainless U-joints (at $91 per). They are said to be in stock so I should see them shortly. I'll let you all know,
I appreciate all your comments.
Buzz (MoonBat)

 

[57Nomad]

You will be very pleased with Borgeson 3/4 DD shaft stainless U-joints. They are all I use. I have found them from other sources on line for under $40. But that is water over the falls.

This one is with aftermarket power steering on ‘68 Corvette. You can see joint under the power brake booster. I only needed one to replace the typical rag joint. Typical applications they are in pairs.

 

[MoonBat]

You will be very pleased with Borgeson 3/4 DD shaft stainless U-joints. They are all I use. I have found them from other sources on line for under $40. But that is water over the falls.
View attachment 527332
This one is with aftermarket power steering on ‘68 Corvette. You can see joint under the power brake booster. I only needed one to replace the typical rag joint. Typical applications they are in pairs.

You will be very pleased with Borgeson 3/4 DD shaft stainless U-joints. They are all I use. I have found them from other sources on line for under $40. But that is water over the falls.
View attachment 527332
This one is with aftermarket power steering on ‘68 Corvette. You can see joint under the power brake booster. I only needed one to replace the typical rag joint. Typical applications they are in pairs.

Nomad,
Thanks for your reply.
Buzz (MoonBat)

 

[MoonBat]

Oh Frabjous day ! Callooh ! Callay !
(The Jabberwocky. Lewis Carroll).
My two Borgeson (made in the USA) U-joints hav arrived. They are beautiful and (best of all) they FIT my Borgeson 3/4 DD shaft perfectly. Thet are more expensive but have needle bearings and are said to last 10 times as long.
I can't vouch for this but I am told that there are (at least) THREE 3/4 DD sizes- Europe / United Kingdom, Far East (China et al) and North America (USA). After my (frustrating) experience, I say "USA, all the way."