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Hex for bolts

Started by kvt85, Nov 15, 2024, 06:00 PM

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kvt85

Ok,  what would be the best Hex for a bolt.   Have an antique engine,   and have to make a new bolt to hold the cyl/head on.   The head and cyl are all one piece of cast.   One of the bolts that I took out is bad and I will have to replace it.  Then went to looking and most of the 7/8 inch hex that I find is 12L14,  but what would people recommend for for bolts this size.   It is a 4HP, single cyl,  Do not know what the cyl pressure will be,  Have to replace the rings and stuff on it.   Was using oil,  etc.   But what do you expect on a 100 year work engine.   
Your suggestions will be greatly appreciated so I do not go buy the wrong hex.   Ken

34_40

I'm sitting here trying to remember which engine(s) had 1 piece head/cylinder..  :smiley_rolling:   I've got a Fairbanks Morse model ZZ 2 hp hopper cooled.  It's throttle governed, not hit / miss.  Anyway, like most very early motors - they are low compression,  like 6:1 ,  so a high tensile fastener won't be required.  I believe most all of the ones in my motor are maybe gr5.   

4GSR

Ken,

Let me check my stock here. I may have a piece here that would be much better than 12L14.  What thread by length is the bolt? May have something here that will work, too.
Ken

kvt85

Sorry  have been off the net for a few days.  I will check on the length.   It is prob three in inches head and all.  Will check tonight.

kvt85

Quote from: 34_40 on Nov 15, 2024, 08:21 PMI'm sitting here trying to remember which engine(s) had 1 piece head/cylinder..  :smiley_rolling:   I've got a Fairbanks Morse model ZZ 2 hp hopper cooled.  It's throttle governed, not hit / miss.  Anyway, like most very early motors - they are low compression,  like 6:1 ,  so a high tensile fastener won't be required.  I believe most all of the ones in my motor are maybe gr5.   
Mine this one is a Throttle gov,   It is a Cushman 4hp Binder,   I also have a 3HP Fairbans Morse, Nelson Brothers 1 3/4 hp,  Sattley  1 1/2 Hp,  and a maytag 72,  At this time.

34_40

Sweet collection.  :smiley_frog:  I have this F-M and "most" of an IH , I thinks it's 1 1/2 or 2 hp.  I had this F-M driving a power hacksaw when we'd go to a show.  I didn't keep the saw on this recent move so it just sits in the garage at the moment.  Not sure what I will do with it.

chips and more

Is it going to be restored to show condition? Is it a special size bolt that cannot be store bought?

4GSR

KVT, I checked the material I have on hand, it checks around 80 HB. Dead soft! So it's 12L14.
I tried.

I think it was mentioned, On McMaster-Carr website, you can purchase heavy hex bolts that for a 7/8 hex, the threaded part would be 1/2-13 UNC. You may already know this.

Ken
Ken

4GSR

Wow! I had no idea that stuff was that expensive.
Ken

4GSR

Here's a listing for heavy hex bolts from McM-C.
Ken

kvt85

here is the shot of the bolt.   2Inch total length.   7/8 head 5/8 shaft 11 threads.   But the head is about twice the height of the a normal head.   

kvt85

Quote from: chips and more on Nov 18, 2024, 02:58 PMIs it going to be restored to show condition? Is it a special size bolt that cannot be store bought?
No will not be a full restore,  It will be in shows so I will want it to look correct,  Most of the big bolts and nuts seem not to be normal sizes,  Like the nut on the crank is also an odd size and 6tpi,   And all the main bolts have double hieight head.

4GSR

You going to have to get a piece of 4140 round bar and turn it down and thread. Then put in the mill and cut a hex on it. Might as well make a full set to replace them all, however many that would be.
Ken

chips and more

If you had a means to test its hardness? I'll bet it's like 1018 steel or something like that and partially forged giving it a little extra strength with machined threads. Looks easy enough to make. Maybe from the 4100 HT series if you had toughness concerns?