Ba studs

Hi All,

This thread (no pun intended) started off a thought process as to the advantage of studs vs studding. I understood that studs were used to allow different threads to be used, e.g. in a cast iron or aluminium casting a coarse thread would be used, while for the fixing nut a relatively fine thread would be used - e.g BSW at casting end and BSF for the clamping nut.

The theory, as I was led to believe, is that the coarse thread was less liable to be pulled out of the weaker or brittle material while the finer thread of the nut allowed a greater clamping force for a given torque.

Hence the use of studs in models with the same thread both ends has no significant advantage, not even an aesthetic one as they cannot be seen. If aesthetics is important on early historic models surely it is more important to use square nuts as would be originally used. Strength of the stud would not be a factor as there must be extra redundant threads below the fixing nuts.

Can anyone explain what other advantage there is that I may have missed?

Best Regards

Terry

Edited By Terryd on 27/10/2012 12:04:14

One reason for using proper studs if that the end can be threaded to a set length so that when you screw it into the hole it will protrude by a known amount regardless of how many turns the tap had threading the hole. This helps ensure that when everything is assembled you end up with the right amount of stud above the nut, especially on parts with lots of studs that may come in & out several times.

Also having a plain centre section allows you to grip the stud without crushing the creasts of the thread.

The cost of studding can soon mount up, eg 8BA costs around £5.50 a foot but a similar length of rod cost say 50p

If the original engine had square nuts then I would make square ones to screw onto a proper stud, this is a pic of the fixings for a hit & miss all made including the ones with square heads on teh set screws, no hex sockets here.

J

Thanks Jason,

Those are good enough reasons for me, Studs it is.

Best regards

Terry

Copper plated plain welding rods are just the right size for 10BA studs and nice and soft so they don't ruin your dies. You can even gently run a 10BA die down a long (well lubricated) length of it under power without trouble.

Neil

One thing with studs, the plain unthreaded part is the full diameter, this may or may not be an advantage, other than that, all thread/studding is usually OK, unless as Terry says there is two different threads. On some special studs, the plain part is actually reduced in diameter, sometimes on a long one there is a short section at half way of full diameter. Ian S C