source of steel to mill block for RT?

Well, I have another challenge, and I need some help.

The missing block that I am making is the one on the left hand, and as it happens, it is a left handed thread. The thread is M8 x 1.25 LEFT. What would you guys recommend? Trying to create the bolt from scratch in my lathe, or try to find a M8x1.25 Left Hand Die to make the bolt?

Ideas, suggestions?

Will
 
wquiles said:
Well, I have another challenge, and I need some help.

The missing block that I am making is the one on the left hand, and as it happens, it is a left handed thread. The thread is M8 x 1.25 LEFT. What would you guys recommend? Trying to create the bolt from scratch in my lathe, or try to find a M8x1.25 Left Hand Die to make the bolt?

Ideas, suggestions?

Will
Click to expand...

Do you want to track down a left handed die and buy it to make this one bolt? Will you find another job for the die if you buy it? I've read the post you made where you made your own threading tool, since you know how to make a threading tool know how to use it, the obvious answer would be for you to make your own bolt assuming your lathe will do left handed threads. You could use use a right hand threaded bolt of a larger size, with the head you want and turn it down to size then thread it with the left handed you need. Does this sound feasable / sensible to you?
 
Having a lathe means you can do things like this. Are the other bolts socket head? If so then just get one with a matching head but longer, and thread it on the shank as required. Then part it off to make the length you want.
 
Well, you guys convinced me - I will turn my own bolts. There is always a first time for everything, right?

Besides using a larger bolt to start with, what other materials do you guys normally use for making your own bolts?

Will
 
Well my only tip is if you use the modified flank in feed ( where you set your compound at 29° ) make sure it really is 29°.

Your lathe and others will have it wrong if you use the engraved scale as in your pic. A quick check is that the side of the compound must be parallel with one of the sides of the insert or single point 60° tool.

Get this wrong and you have very odd looking threads. Its caught us all out at one time or another.


 
Anglepoise said:
Well my only tip is if you use the modified flank in feed ( where you set your compound at 29° ) make sure it really is 29°.

Your lathe and others will have it wrong if you use the engraved scale as in your pic. A quick check is that the side of the compound must be parallel with one of the sides of the insert or single point 60° tool.

Get this wrong and you have very odd looking threads. Its caught us all out at one time or another.
Click to expand...

I think Will's compound might be welded in the position it's in. :crackup: Just teas'in Will (inside joke).
 
wquiles said:
Well, you guys convinced me - I will turn my own bolts. There is always a first time for everything, right?

Besides using a larger bolt to start with, what other materials do you guys normally use for making your own bolts?

Will
Click to expand...
"Larger bolt" is subjective. You just need enough material to work with.

A hex head bolt can be made but there are many different dimensions and forms that need to be held within tolerance. If you do not have one get a Machinery's Handbook. A socket head cap screw would be very hard to make. Bolts are often heat treated also, not just simply machined out of a block of metal.
 
Anglepoise said:
Well my only tip is if you use the modified flank in feed ( where you set your compound at 29° ) make sure it really is 29°.

Your lathe and others will have it wrong if you use the engraved scale as in your pic. A quick check is that the side of the compound must be parallel with one of the sides of the insert or single point 60° tool.

Get this wrong and you have very odd looking threads. Its caught us all out at one time or another.
Click to expand...
Thanks for the tip David 😉


Mirage_Man said:
I think Will's compound might be welded in the position it's in. :crackup: Just teas'in Will (inside joke).
Click to expand...
Well, I think that this time, I will "have" to use the 29Deg position. You know it was going to happen sooner or later :naughty:


Torque1st said:
"Larger bolt" is subjective. You just need enough material to work with.

A hex head bolt can be made but there are many different dimensions and forms that need to be held within tolerance. If you do not have one get a Machinery's Handbook. A socket head cap screw would be very hard to make. Bolts are often heat treated also, not just simply machined out of a block of metal.
Click to expand...
I got some bolts at the local Home Depot today, and I just tried cutting them (after cutting the head off), and I think it will work OK for this application. I also changed the external gears to go form my normal 20TPI to Metric 1.25, so maybe tomorrow I can give this a shot 😉

Will
 
Last edited:
what other materials do you guys normally use for making your own bolts?
Click to expand...
Probably the #1 choice is 4140 Prehard, which is regular 4140 that's been heated, oil quenched & tempered to Rockwell 28-32. That makes it as hard as a typical Grade 5 bolt, but still easy to turn, thread, & mill the flats on. This is a tougher material, and you'll want to run no faster than about 100 sfpm with carbide tooling, or half that with HSS tools.

Choice #2 is 1144 Stressproof. Not as hard (unless you heat/oil quench/temper) but easier to work than 4140PH. Tensile & yield are almost as high as 4140PH.
 
I love to work with 4140 but then I made a lot of large plastic pipe extrusion dies from that material.:twothumbs

Will, why didn't you just buy bolts with the head you needed and just thread the shank? Even metric bolts do not have thread all the way to the head if you buy them long enough. They are harder to find tho. Even after many years we still do not have a decent selection of metric fasteners in the US. Hacking a complete bolt or screw out of a hunk of metal is fun but it is kind of a waste of time.
 
Torque1st said:
Will, why didn't you just buy bolts with the head you needed and just thread the shank?
Click to expand...
Because the so called bolt is not a "normal" bolt. Look at these pictures to see what I mean. In the first picture, right below the steel block, you can see the two part lever: bolt and extension, which is keep in place by a set screw on the flat side of the bolt:
dscf4815.jpg



Here in the second pic you get a closer look at the bolt part:
dscf4820.jpg



Plus part of this is the fun in trying to re-create something. Remember that for a newbie like me, these projects help me learn more :devil:

Will
 
Gees - doesn't need to be hex, a low stress situation (not holding a heck of a lot)

Remember the thread where we talked about "Buying a couple of sticks of steel of different sizes to keep around"? This is the time to grab a stick of "whatever" (Stressproof would be good, 4140 prehard better, but I'd bet that 12L14 would work fine for the amount of stress that bolt will be under) and hack away at it. If you mess up, all you'll have lost is a few cents in steel, and some time, but you'll have gained in knowledge
 
For those clamps any old steel will work. Just be able to adjust them with shims or with a locknut so that the handle operates over the proper range.
 
Torque1st said:
For those clamps any old steel will work. Just be able to adjust them with shims or with a lock nut so that the handle operates over the proper range.
Click to expand...

Or once the part is threaded put it in, torque it, and mark the location for the handle.
 
wquiles said:
Plus part of this is the fun in trying to re-create something. Remember that for a newbie like me, these projects help me learn more :devil:

Will
Click to expand...

This is why I was wondering what the best way would be to match the arc on the block. Not so we end up with a thing of beauty but to test our abilities of making the hardware do what we want it to!

This is a great learning project!
 
Just to play with, I turned down a 5/8" steel Grade 5 Hex bolt from Home Depot. I then tried to thread a smaller diameter section (0.313"), but like you guys warned me, it was not fun. I also tried with 5/8" drill rod - not fun either. It was still good practice doing left handed threading, so it was time well spent.


KC2IXE said:
Gees - doesn't need to be hex, a low stress situation (not holding a heck of a lot)

Remember the thread where we talked about "Buying a couple of sticks of steel of different sizes to keep around"? This is the time to grab a stick of "whatever" (Stressproof would be good, 4140 prehard better, but I'd bet that 12L14 would work fine for the amount of stress that bolt will be under) and hack away at it. If you mess up, all you'll have lost is a few cents in steel, and some time, but you'll have gained in knowledge
Click to expand...

Tomorrow I will visit Metals4U and try to buy some 1144 Stressproof stock to use for the actual bolts and handles, although I will likely also buy some more 12L14 to have around for similar projects 😉

Will
 
Last edited:
precisionworks said:
Murphy's Law, as applied to machined parts, clearly states that the handle will always end up in the wrong place😀

You may want to consider adding an adjustable handle to the bolt:

KHB-16_ImageC.jpg


http://www.reidsupply.com/GrpResults.aspx?PID=10021791&APID=10021791&AID=KHX-35&ST=&BI=
Click to expand...

Good idea, but I will be making my own, and using a set screw to keep it in place, just like the Yuasa original handles. I just wish I had a ball turning "adapter" for my lathe - or better yet, maybe I should try "making" one 😉

Will
 
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