Stud torgue lightly?

Reviewing engine building sites reveals basic advice to only tighten studs to seat fully by finger torque only so ask does this also apply to our engines? I use red loctite on studs but prior have used pilers to snug studs down and wonder if I'm misguided on that?

In theory, a properly designed stud installation will have a tighter interference fit for the threads on the end that goes in the threaded hole, and a looser fit on the threads that take the nut. If all the threads are clean, that helps keep the stud in place when removing the nut. The trouble with bikes is that the nut frequently gets locked on the stud with corrosion, and then the stud comes out when trying to remove the nut. Also, with studs in aluminum castings, the fit loosens up after the stud is removed and replaced a couple times. Loctite or other adhesive bonding when installing the stud helps a lot, but the stud will still sometimes come out with the nut if there is corrosion. In a lot of industrial applications the use of an adhesive bond on the stud is normal practice.

I'm not so sure about the finger tight part. If you have the tighter fit for studs that aren't intended to be removed often, you can't screw in the studs without a wrench or stud tool unless you have pretty incredible finger strength. The usual warning from the stud manufacturers is to not over-tighten the studs against the bottom of the threaded hole, because that pre-loads the threads, defeating some of the holding force when the nuts are torqued. I'm not sure how significant that is in most of our applications. I think most of the stud failures in our Commandos are a result of over-tightening by owners, maybe compounded by the designers' choice of fine threads to hold the studs in aluminum castings.

Ken

OK that agrees with what we all mostly do but Ugh also implies you do not know either so will have to ping some other non Norton experts to get all the factors that might apply to us. Not completely an academic question though as I had studs twist out with nut on cylinder, head and cover fasteners on Commando and lawnmower but got away long term with just leaving nut fixed to screw back in - but- you have alerted me that that would tend to put too much torque on Alu threads as stud turns not just nut. I stumbled across this finger tight only statements > looking up the torque vs stretch references we bickered on recently. Still just because I got away with twisting studs by nut to full torque back in does not mean I have not messed with next owners frustration level of my non expert mechanic mischief. Unless some thread damage its only first 2-3 end thread that carry 90+% of clamp force so hope to avoid that. Catch 22 is if stud not tight enough then backs out but if too loose beats snot out of thread, ugh. Sometimes I feel like just welding engine together and may actually do that at some point.

If the stud becomes tight in the thread, the tightness should be at the bottom of the tapped hole and away from the outer surface that the hole is tapped into.
The shank of the stud should never be forced against the surface and causing any distortion. That could cause cracking at the surface, or surface distortion.

Screwed in lightly with BLUE Loctite is usually fine. Red Loctite is way over-kill and likely to create more problems if you ever have to dismantle it.

Where practicable (into aluminium) I chamfer the lip to reduce mounding, helicoil the hole to increase strength, locktite the stud in to improve retention, nip them up with vise grips on the waist for tightness and (depending on the application i.e. footpeg mount studs) apply anti-seize to the nut threads for corrosion resistance.
Ta.

Ah so Needing good point about "mounding" which I've seen in many places besides Nortons. I've followed all the above methods of stud installs, including chambering both the tapped hole as well as one side of a nut's hole - not knowing which was better - as all of em held within my ability to tell. Found these two short video that explain more on stud install priniciples.
https://www.youtube.com/watch?v=3EQcsP2PUXQ
https://www.youtube.com/watch?v=Lk7H3TIZSNM

and form this offical ARP site: http://arp-bolts.com/p/FAQ.php
Do the head studs only go in hand, or finger tight?
Yes, cylinder head studs are installed only hand tight. Other than the use of an allen wrench on the hex broached into the end of the stud (to ease installation, not to apply torque), use no tools to seat them in the block. However, it is extremely important to ensure that the studs are fully bottomed out in the hole in the block and not hung up on damaged or corroded threads in the block preventing the stud from being fully seated. This is often indicated when the stud threads extend past the deck surface.

Ah hobot
My example was for through-holes like footpeg mounts or primary case mount holes (front and upper) in LH crank case.
UNC studs threads fix 'permanently' into the aluminium so the nuts can be torqued onto UNF threads repeatedly.
I dislike torquing UNC setscrews into aluminium repeatedly (torque control is better for UNF).
I particularly liked the ball in the blind hole in one of the video links you posted.
Ta.

I've always tightened them in tight, using double nuts so I can tighten with a spanner (wrench to you non English speakers) and a drop of stud lock as well.

My thinking being they need to be in tight for the threads to 'function' correctly, but also, I want them staying put when I remove the nuts off of them at any point afterwards.

Well the main point of using studs they say is so only the nut turns to releive torque twist on stud but if we don't tighten pretty good &/or glue our Norton studs in they tend to act like twist bolts with nut as the head, ugh. I'm been able to remove red loctited studs in alu out with heat and double nuts so studs being mostly permanent that's what I try to use for glue and maybe it helps fill in thread gaps so spreads loads among all the threads better.

Hi,

I always tighten studs with a spanner (usíng double nut) but with very low torque and loctite.

Ralf