Need to make bolts--What type of steel?

In my experience in restoring old machinery I've not found high tensile fasteners anywhere. Granted, I work on Steam engines! Most of what they're made if isn't even classed as steel in modern terminology, having had some parts metallurgically analysed. Depending how old your engine is you may well be in a similar situation.

With respect to that: be careful putting a high strength fastener where there previously wasn't one. Sometimes a lack of give in a fastener can spell disaster for whatever ancient casting it's clamping or threaded into. It depends exactly what you're doing, though.

Love to see what you're working on!
 
Downunder Bob said:
We fouind this out years ago when Australia was still very much BSW and we were working on imported (USA) vehicles. UNC nuts and bolts were hard to find, except as geniune spare parts which we could not afford.
I have lso used my 60 deg threading tool frfequently to cut BSW threads with no ill effect.
Click to expand...

Ah yes! I learned a number of things like this working on my first car, a '51 Riley DHC. I forgot most of them after parting with my second, and last, English car, a '59 MGA. The most important lesson I learned was never buy an English car.
 
Thanks for all the help. Oddly enough, I do have a set of taps (taper, plug and bottoming) and a die for 1/2-12. 1/2-12 was once not an uncommon pitch before thread pitch was standardized. I have ran into it before. It is not BSW.

My main question was around what kind of steel threads nicely. The different properties of steels is one area I don't know much about. I am wanting something that will form nice threads. I have threaded unknown steel in the past that more tore threads and the threads were very rough. I don't want to repeat that experience.

I do have a mill, so making the flats is not a problem other than it is one more step to do.
 
gasengin said:
My main question was around what kind of steel threads nicely. The different properties of steels is one area I don't know much about. I am wanting something that will form nice threads. I have threaded unknown steel in the past that more tore threads and the threads were very rough. I don't want to repeat that experience.
Click to expand...

Both of my earlier recommendations provide very good to excellent machinability, with Stressproof being the better of the two. For the very best in machinability, 12L14 is as good as it gets. It has a tensile strength of 60ksi, Stressproof is 115ksi and ETD150 is 150ksi.
 
gasengin said:
Thanks for all the help. Oddly enough, I do have a set of taps (taper, plug and bottoming) and a die for 1/2-12. 1/2-12 was once not an uncommon pitch before thread pitch was standardized. I have ran into it before. It is not BSW.

My main question was around what kind of steel threads nicely. The different properties of steels is one area I don't know much about. I am wanting something that will form nice threads. I have threaded unknown steel in the past that more tore threads and the threads were very rough. I don't want to repeat that experience.

I do have a mill, so making the flats is not a problem other than it is one more step to do.
Click to expand...

You say its 1/2"12 but not BSW. 1/2"BSW is 12TPI so by what measure is it not BSW. At that size can you actually measure the difference between 55 and 60 deg. Especially if it's worn.

What make of engine is and where were they originally made.
 
You must log in or register to reply here.
Back
Top