Studs vs bolts?? Pros? Cons?

[ebinmaine 63,327]

There are certain places on our tractors and other machinery that I find a stud with nut is easier to install than a bolt. 

 

A couple examples:

Wheel to hub. Many of us are well aware of this conversion. 

 

What about for attaching transmission to frame?

Would there be a negative effect of using studs screwed into the transmission case so the frame is easier to line up?

 

[ri702bill 7,382]

Transmission - maybe. Four studs, or setscrews, of the same length would be a bear (pun intended) to re-install onto a fully dressed frame.

Perhaps only one or two....? Also, a commom Machine Building trick is to NOT use two studs of the same length. One slightly longer to pilot into the first hole, makes the lineup easier for the second..  I use a pair of short, 1-1/2" long 3/8-16 pieces of threaded rod screwed into the Unidrive to replace the two bottom bolts FOR REASSEMBLY. Mate it up, put in the top 2 bolts, remove the studs, install the lower bolts. I recall it is not too easy do do this on the uppers with the clutch rod in the way...

I am Old School on the hubs - I altered a pair of old Chevy rear axle lug studs (7/16-20 thd) for removing and installing rear wheel & tires.....

[ri702bill 7,382]

Another possible place may be at the carbureator to engine - helpful to hold the gasket in place....

[ebinmaine 63,327]

29 minutes ago, ri702bill said:

 replace the two bottom bolts FOR REASSEMBLY. Mate it up, put in the top 2 bolts, remove the studs, install the lower bolts. I recall it is not too easy do do this on the uppers with the clutch rod in the way...

 

 

 

Good information on the clutch rod.

This is kind of the line of thinking I was after but is there an actual specific reason why I would need to remove the two bottom studs instead of just installing nuts?

[ri702bill 7,382]

Actually, no - but that leaves 2 posibilities on each to vibrate loose....... bolts leave only one. 

 

So you plan on playing "Musical Unidrives"???   

[ebinmaine 63,327]

3 minutes ago, ri702bill said:

Actually, no - but that leaves 2 posibilities on each to vibrate loose....... bolts leave only one. 

 

So you plan on playing "Musical Unidrives"???   

I could use lock washers or Loctite. 

 

The question arises because we're swapping frames on the C121 Automatic for my parents. 

Frame to transmission isn't too bad but there'll be a lot of other things in place. Not just bare frame. 

[ri702bill 7,382]

Original fasteners were Grade 5 - setscrews usually are, threaded rod is NOT.

[ebinmaine 63,327]

I switched over to using grade 8 for almost all of our fasteners a few years ago. Likely I'll just take a couple of those bolts and cut the heads off to use as studs.

[kpinnc 10,864]

1 hour ago, ebinmaine said:

switched over to using grade 8 for almost all of our fasteners a few years ago. Likely I'll just take a couple of those bolts and cut the heads off to use as studs.

 

I can certainly see the benefit. Use thread locker just in case.

 

Or... Use long setscrews so they can be torqued when needed. 

 

Edited March 20 by kpinnc

[squonk 39,011]

You want to make it strong? Switch to fine thread. My Power King is all fine thread except for the std. Kohler bolts. You need power tools or your wrenching on it all day.

[ri702bill 7,382]

2 hours ago, squonk said:

Switch to fine thread

I respectfully disagree in this situation.

Two reasons:

Unless you use dis-similar threads on the studs, you normally do not use fine threads in cast iron or aluminum. Seen carburetor to intake studs like that back in the '70's. Coarse threads into the intake, fine threads to attach the carb..... Retapping the Unidrive to fine threads - not a great idea... 

 

[squonk 39,011]

Never said to do it. Just commenting on the strength of fine thread. Maybe misunderstood what I was driving at

Edited March 20 by squonk

[ebinmaine 63,327]

2 hours ago, squonk said:

need power tools

I've been using my power drivers for years. 

 

BBT still uses cave dweller tools like 🔧🔧 and ratchets. 

[ri702bill 7,382]

Because they work when the lights go out and you can't run a compressor or charge batteries.  OLD SCHOOL.

[squonk 39,011]

Changing the hyd. belt on my PK requires removing the engine. I had to take some bolts out  that only a ratcheting wrench could get to. Had to keep taking coffee breaks! 

[8ntruck 6,419]

Fine threads are more resistant to loosening under vibration due to the lower angle of the thread.  They are also a bit stronger due to the larger root diameter of the thread.

 

I've had to change to fine threads to hold details in a few of the dies I was working with because the coarse thread bolts would loose torque, then fail.  The 4000 ton press didn't care about the broken bolt piece in the die and went over anyhow - resulting with damaged die details, scrap parts, damage to the following dies, etc.  Sometimes had to redesign the troubled details to get more load bearing area.

[pfrederi 17,170]

My 1953 M-37  has nothing but fine threads Uncle wanted strength.   There are some engine bolts (Dodge) that are coarse>

[Lee1977 6,259]

On 3/20/2024 at 4:34 AM, ebinmaine said:

There are certain places on our tractors and other machinery that I find a stud with nut is easier to install than a bolt. 

 

A couple examples:

Wheel to hub. Many of us are well aware of this conversion. 

 

What about for attaching transmission to frame?

Would there be a negative effect of using studs screwed into the transmission case so the frame is easier to line up?

 

Trina does all the heavy lifting, disassembly, painting and assembly. You trying to lighting her work load?

[ebinmaine 63,327]

1 minute ago, Lee1977 said:

Trina does all the heavy lifting, disassembly, painting and assembly. You trying to lighting her work load?

 

Absolutely. Why not?