Studding in blind holes

[SignalFailure]

Is using studs and nuts in blind holes considered good or bad engineering practice if there's no possibility of a through-hole? Would a screw/bolt be better or does it depend on the load?

TIA

Paul

 

[MachineTom]

All studs I've ever seen are in blind holes that why they are used in the first place. Is that what you looking for?

I do know of a large stationary steam engine where the flywheel halfs are bolted to the hub with studs that are thur. about 5" D and 6' long. Thats the only case I can think of a stud used in a thur hole.

 

[SignalFailure]

Thanks MachineTom. For some reason I've got a nagging thought that studs&nuts are better than screws but only in some circumstances....

 

[DickDastardly40]

Paul,

Further to Tom's answer you can screw bolts or cap head screws (don't know why they're called screws not bolts) into blind holes you just need to be sure they don't bottom out as you won't get whatever your bolting down tight.

Al

 

[Lew Hartswick]

Paul,

(don't know why they're called screws not bolts)
Al

According to the "bible" ( Machinerys handbook) A SCREW is a device which is installed
by turning the head. A BOLT is installed in a hole and is tightened by turning the NUT
on the other end. [partially simplified]
The go on and on covering machine, wood, selfthreading, etc screws.
SO! I detest it when people refer to LAG SCREWS as bolts, there isn't any nut involved.
...lew...

 

[Mainer]

When I was debating the bolts/studs question for my "Unicorn" model, I opted to use bolts on all the through holes and studs and nuts on all the blind holes. The result "looks right," at least to me. Though I'm not sure, I think that was traditional practice.

These days I think bolts are being used in places where formerly studs might have been the choice. Maybe it's because bolts are easier to make now than they used to be???

Studs have a locating value as well, that bolts don't have. You can drop the mating part onto the studs and it will stay where it's supposed to be, instead of having to hold the part in place while you try to get a bolt started.

 

[Foozer]

Studs also have a better torque holding (lack of proper term) ability than bolts in blind holes. Torquing a bolt by the head imparts some twist as well as stretch and too easy becomes "Its getting looser - SNAP"
With a stud torque is applied via the nut as it should be avoiding the twist.

Broke enough bolts, really prefer studs when possible.

Robert

 

[Metal Butcher]

Is using studs and nuts in blind holes considered good or bad engineering practice if there's no possibility of a through-hole? Would a screw/bolt be better or does it depend on the load?

TIA

Paul

Whether or not you use/have a threaded through hole has no bearing on a decision to use studs with nuts, or bolts. As far as load goes, the correct amount of thread depth for the material the bolt or stud goes into is the only thing (standard engineering practice) you need to be concerned about.

If the use of studs and nuts is called upon for cosmetic reasons, then by all means go that route. Its takes more time to cut a stud, thread both ends accurately, install it at the appropriate height, and the add the nut. With a bolt, you just add the bolt.

On the small stuff that I build I tighten small bolts very lightly. If you have concerns about stripping out threads, then a small inexpensive inch/pound torque wrench would solve the issue, along with the use of the chart I'm posting a link to.

http://www.thelenchannel.com/1torque.php


-MB

 

[Jasonb]

For models of older engines then studs look right as its what would have been used originally on the majority of blind holes. If you do go with studs then make proper ones with a thread cut either end of a length of bar, don't be tempted to use studding (allthread) as it does not fit the clearance holes as well.

There is a risk when using bolts/screws into blind holes that they may bind onto a too short tapped hole and you may think they are tight when infact the head may not be bearing on the work.

Jason

 

[t_ottoboni]

As far as i know, studs are used when the threaded part is made of a brittle material, such as cast iron, and the frequent removal and installing of a screw would damage the thread. So a stud is used to reduce the possibility of damage in case of frequent disassembly.

 

[Mainer]

There is a risk when using bolts/screws into blind holes that they may bind onto a too short tapped hole and you may think they are tight when in fact the head may not be bearing on the work.

Jason


Good point, Jason. That may be a major reason why studs were (and are) used in blind holes. It may have been especially true in "the old days."

 

[SignalFailure]

An excellent set of replies, excuse me for not replying to them all! All the info I need is in there so thanks all

Paul

 

[Maryak]

When a bolt is tightened the bolt is subject to twist and stretch. If done correctly when a nut is tensioned on a stud the stud is only subjected to stretch. On HP steam systems we used studs and nuts and the correct tension was determined by the stud elongation.

Hope this helps.

Best Regards
Bob

 

[bob ward]

I tend to be a stud and nut person where possible. My main reason is that a stripped stud can readily be replaced, but a stripped thread in a blind hole presents more serious problems.

 

[Marinesteam]

Hey all,

Studs are appropriately used where:

- The cost of replacing or repairing a damaged thread is high. example: A casting or other complex/ expensive part

- Assembly is made easier by being able to use the stud to "hang" or locate a part on before bolting up.

- Multiple parts are bolted up using the same fastener(s)

- The size of the part being bolted on necessitates the use of an overly long bolt.

Steam engine valve covers are a good example of all of these

There may be some others as well.

Ken