Need to make bolts--What type of steel?

[Tozguy]

Could you start with a bigger version of an existing bolt and machine it down to what you need? Might save some time.

I have done this many times with different grades of bolts with great results. There is a local machinery supply that has a huge selection of fasteners and I can get any grade of steel bolt that is called for.

Needs both a special head and odd thread pitch (1/2-12). It is for an antique engine before the 13 thread standard.

What is special about the head?
Thread pitch would not be a problem if the bolt is long enough to cut the threads off and use the unthreaded portion.

 

[gasengin]

What is special about the head?
Thread pitch would not be a problem if the bolt is long enough to cut the threads off and use the unthreaded portion.

The head needs to match the rest of the bolts on the engine. The bolts have a taller head than modern bolts and a rounded top.

Are these head bolts for a hit and miss engine? I agree the ETD150 is best.
Cheers
Martin

Yes, it is for a hit and miss engine

Thanks for the information, I will have to decide which of the two to use. I doubt the original bolts were even equivalent to grade 5 bolts.

 

[tq60]

Grade 2 maybe...

Get some cheap as you can get hex stock same size as nut if hex, 0.775 across flats or whatever the head is.

Practice on this making the head, then you have options...

Cut down to make bolt.

Drill and tap head thread pitch standard to make it a nut.

Purchase suitable 1/2 bolts long enough to have non threaded area to length needed as well as practice material if needed.

You will screw the threaded part into your made nut and weld over the top then machine it to clean up top after finished.

Thread the straight shaft to needed pitch and fit.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Illinoyance]

If it is for a hit or miss engine I seriously doubt that high strength bolts were used. That means you could make the bolt out of almost any kind of steel. If possible buy a piece of hex stock to eliminate the meed to mill the hex.

 

[hman]

Needs both a special head and odd thread pitch (1/2-12). It is for an antique engine before the 13 thread standard.

½-12 ain't just for breakfast any more!

It's still in use, at least in China. I've run into this thread pattern on recent hardware twice in the last year. The first was the caster stems on a store fixture I was repairing for a friend. More recently, the motor mount (belt tightening) studs on my new PM835S mill. I've been thinking of replacing the fixed speed motor with a 3 phase and VFD. I'll probably end making entirely new tighteners based on ½-13 thread.

I've also been giving semi-serious thought to purchasing a ½-12 tap and die ... wondering if the cost would be worthwhile. Here's what I've found, for your dining and dancing pleasure:
McMaster wants $68.81 for the die, $38.62 for the plug tap:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Amazon has a rethreading die for $11.91

Amazon.com

... and a tap-and-die set for $9.70 (probably good for one or two holes in soft materials?)

Amazon.com: 1/2-12 Hss Tap And Die, UNC Machine Thread Tap And UNC Round Thread Die Right Hand : Industrial & Scientific

Buy 1/2-12 Hss Tap And Die, UNC Machine Thread Tap And UNC Round Thread Die Right Hand: Threading Taps - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Victor has a tap for $14.20

1/2-11 Special Pitch Tap, High Speed Steel

1/2-11 Special Pitch Tap, High Speed Steel

www.victornet.com

MSC wants $44.43 for such a tap

https://www.mscdirect.com/product/details/65680365

 

[Illinoyance]

Avoid the uxcell tools at Amazon. Most are junk. Victor Machinery and Travers tool are good sources for non standard taps and dies. Avoid re-threading dies.

 

[Downunder Bob]

Needs both a special head and odd thread pitch (1/2-12). It is for an antique engine before the 13 thread standard.

!/2" 12 thread sounds like BSW. depends on where you are a specialist fatener supplies should be able to get in grade 5 and 8 with hex heads or as socket head cap screws.

 

[Cooter Brown]

Needs both a special head and odd thread pitch (1/2-12). It is for an antique engine before the 13 thread standard.

Was it made in china? The number 13 is a deathly unlucky number in china that scares everyone so much that they wont cut 13 TPI so lots of tools from china have 1/2-12 or 1/2-14 screws...... I have a china bench grinder I lost a nut to and its 1/2-14.....lol

 

[MrWhoopee]

Remember that BSW (Whitworth) is a 55 ° thread, not 60 ° .

 

[Downunder Bob]

Remember that BSW (Whitworth) is a 55 ° thread, not 60 ° .

Yes so it is, however in actual practice it makes very little difference, I have found in most cases commercial grade BSW and UNC will fit each other with of course the exception of 1/2" High precision bolts and nuts can be a little tight.

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.