# Precision Ground mild steel?



## Kevinb71 (Aug 1, 2012)

I am going to begin collecting materials for a GHT Pillar tool I want to make. The metal that the book I am following suggests is P.G.M.S. (precision ground mild steel). I do not find any listing for it that way. Would 12L14 make a good shaft for the pillar or how about stressproof, 4140 or 1045? All come ground. Is there another material that would be better. The steel alloys always confuse me yet! Can anyone recommend a rookie guide to using steels and other metals?


----------



## randyjaco (Aug 1, 2012)

What is a GHT Pillar tool?

Randy


----------



## November X-ray (Aug 1, 2012)

What this sounds like is TGP shafting (mild steel that has been turned, ground and polished) and assuming you need only round shapes this is readily available from suppliers like Speedy Metals, or Online Metals. I believe they may even carry some ground flats in mild steel.

Good Luck in your project!


----------



## Bill Gruby (Aug 1, 2012)

randyjaco said:


> What is a GHT Pillar tool?
> 
> Randy




George H Thompson Universal Pillar Tool.

http://www.amazon.com/Building-the-Universal-Pillar-Tool/dp/0852427859

Billy G" )


----------



## Kevinb71 (Aug 1, 2012)

Bill is right. I should probably have explained that. And Yes it is turned ground polished material, but of what alloy to use! So many alloys so little money. Think of this piece as the "column" for a drill press albeit a small one. Some stiffness of the shaft would be good. It's 15" long and will have a small drill head and other accessories of the top. You can use it for a tapping guide or rivet staking tool. Also for a guide when punching numbers into dials etc.


----------



## November X-ray (Aug 1, 2012)

Hey, I got a little drill press like that my Dad gave me about 20 years ago. He bought it at an estate sale for a few dollars and it did not have a motor. He siad he figured I could use it, now I just need to remember where I packed it away! Thanks for the link Bill!!!


----------



## Tom Griffin (Aug 1, 2012)

If you need it ground to fit a bearing, you'll need to buy shafting so the diameter is slightly under the nominal dimension. McMaster Carr sells some nice black oxide coated shafting that is plus .000" -minus .001". They sell stainless as well.

Tom


----------



## November X-ray (Aug 1, 2012)

Kevinb71 said:


> Bill is right. I should probably have explained that. And Yes it is turned ground polished material, but of what alloy to use! So many alloys so little money. Think of this piece as the "column" for a drill press albeit a small one. Some stiffness of the shaft would be good. It's 15" long and will have a small drill head and other accessories of the top. You can use it for a tapping guide or rivet staking tool. Also for a guide when punching numbers into dials etc.



Please do not take me as being obtuse, but the key word here is "mild steel". This is not an alloy in the traditional sense and as long as you are using steel, not aluminum, copper, pewter, etc. it should work fine. Although you could use stainless steel, or other steel alloys but it will get very expensive quickly!

Good Luck!


----------



## Kevinb71 (Aug 1, 2012)

NX

Speedy metals has several ??? of turned, ground, polished materials. 12L14, 4140, 1045 and stressproof. What is the proper term for these then if alloy is not right. As I said in the OP i get confused by the different metals. Was hoping to find the strengths and weaknesses of each of ??? metals listed. Hope I am not being too basic here. Thanks for the reply!


----------



## Tony Wells (Aug 1, 2012)

Basically, all steels are alloys of  iron and varying amounts of carbon and other elements. Steel is a very versatile material. For your project, the material requirements are fairly generous. There is no need for spending a lot of money on ultra high strength steel for this. The fact that the bill of materials specifies "mild steel", which is a very general description btw, indicates that virtually any steel would be fine. 

In general, steel is categorized loosely by carbon content. What people consider mild steel is usually a low carbon steel. Easy to weld, easy to form, easy to machine. And usually low cost. And not always available in a TGP form. But if you hunt, you can find something in low carbon TGP. Most TPG will be used where the precision given is coupled with other mechanical properties. Pump shafting comes to mind as a relatively low cost material that has reasonable mechanical properties that would be fairly easy to find. Even then, there are alloys to choose from. 

On a small project like this, there is no need for a high strength alloy like 4140, etc. Or stainless. I'd recommend 1144 (Stressproof) or 12L14 in a TGP form. Unless you happen to run across a deal on some high strength alloy to suit your purpose at a bargain, those are probably your best choices.

Here's some light reading on the various alloys:
http://nptel.iitm.ac.in/courses/Web...Material Science/pdf/Lecture_Notes/MLN_09.pdf

Here's some not so light, but has more specific information:
http://85.185.231.196/mekanik/Electromechanical.Design.Handbook/engineereng materials.pdf


----------



## Ken_Shea (Aug 1, 2012)

One of the problems with using 12L14, although it machines like a dream, it also is very susceptible to rusting and not particularly weldable if that is a requirement but don't believe there is any by the look of the picture.
 That unit could likely also use thick wall precision ground tubing.

Ken




.


----------



## Ken_Shea (Aug 1, 2012)

Kevin,
What diameter do you require?

Ken


----------



## Tony Wells (Aug 2, 2012)

There's another chapter to that book. True, Young's is accepted to be 30,000,000 psi for virtually all steel, but the difference comes into the alloy and heat treatment where elastic and plastic deformation occur (different stress/strain curves). Annealed 1010 and 4140 HT will bend just as easily, but the 1010 will take on a permanent bend at a much lower stress point than the 4140. It's stiffness versus springiness.


----------



## Kevinb71 (Aug 2, 2012)

Thanks for all the replies. Tony, I even understood the "light" reading. I think I will go with the stressproof as that is reasonable in price and available.


----------



## KBeitz (Jul 15, 2018)

For the beginner most places that sells steel has hot roll and cold roll.
Hot is soft... Cold is much stronger.


----------

