# Need to make bolts--What type of steel?



## gasengin (Sep 17, 2020)

I am needing at make some special bolts for a project.  I would like them to be at least equivalent to grade 5 bolts.  What type of steel would give me that strength and still be able cut nice smooth threads in it?


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## gradient (Sep 17, 2020)

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


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## silverhawk (Sep 17, 2020)

It actually depends on the bolt. Different bolts of different hardness for different applications. Are you needing a grade 2/5/8? (Lots of other options here, just need to know what you want. )

joe


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## MrWhoopee (Sep 17, 2020)

Stressproof for medium strength or ETD-150 for high strength. Both offer excellent machinability and are available on eBay.


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## gasengin (Sep 17, 2020)

gradient said:


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



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


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## Mitch Alsup (Sep 17, 2020)

MrWhoopee said:


> Stressproof for medium strength or ETD-150 for high strength. Both offer excellent machinability and are available on eBay.



I was going to volunteer 4140 but when I looked up ETD-150 I find it is a near 4140 steel that has been drawn at elevated temperatures--which makes it more suitable for tensile applications.

{Learn something new every day.}


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## dirty tools (Sep 17, 2020)

Contact 
smokestack.com


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## MrWhoopee (Sep 17, 2020)

Mitch Alsup said:


> I was going to volunteer 4140 but when I looked up ETD-150 I find it is a near 4140 steel that has been drawn at elevated temperatures--which makes it more suitable for tensile applications.
> 
> {Learn something new every day.}



At Rc 32 min and 150k tensile, it is roughly equivalent to 4140 quenched and tempered, but it has sulfur, tellurium or selenium added for improved machinability. I'm surprised more people aren't familiar with it.


			http://www.niagaralasalle.com/pdf/etd150casestudies.pdf


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## Martin W (Sep 18, 2020)

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


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## fixit (Sep 18, 2020)

gradient said:


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



Store bought common bolts are crap to machine, just my opinion


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## Tozguy (Sep 18, 2020)

gradient said:


> 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. 



gasengin said:


> 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.


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## gasengin (Sep 18, 2020)

Tozguy said:


> 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.



Martin W said:


> 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.


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## tq60 (Sep 18, 2020)

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


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## Illinoyance (Sep 18, 2020)

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.


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## hman (Sep 18, 2020)

gasengin said:


> 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 Plug Tap, High Speed Steel
					

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



					www.victornet.com
				



MSC wants $44.43 for such a tap


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


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## Illinoyance (Sep 18, 2020)

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.


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## Downunder Bob (Sep 19, 2020)

gasengin said:


> 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.


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## Cooter Brown (Sep 19, 2020)

gasengin said:


> 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


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## MrWhoopee (Sep 19, 2020)

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


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## Downunder Bob (Sep 21, 2020)

MrWhoopee said:


> 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.


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## Lo-Fi (Sep 21, 2020)

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!


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## MrWhoopee (Sep 21, 2020)

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.



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.


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## Tozguy (Sep 21, 2020)

Unless its a Morgan or Lotus or Bugeye Sprite


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## MrWhoopee (Sep 21, 2020)

Tozguy said:


> Unless its a Morgan or Lotus or Bugeye Sprite


And you don't have to rely on it to get to work.


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## Tozguy (Sep 21, 2020)

My Bugeye Sprite was way more reliable than my Chevy Astro.


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## gasengin (Sep 21, 2020)

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.


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## MrWhoopee (Sep 21, 2020)

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.



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.


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## Downunder Bob (Sep 22, 2020)

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.



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.


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