Steel Choice For Threading Then Welding

[mksj]

My experience with 1018 is it basically it is harder to turn, let alone get a decent finish, the 8620 was much easier and also able to break the swarf. The 4130/4140 needed higher feed rate and DOC to get a decent finish and it was a rats nest of swarf. Have to push the cutting very hard to break the chips. The 8620 was much more manageable as to swarf and finish, turns easier then 1144 in my experience, and anything is better than 1018.

Boring 8620.

 

[mattthemuppet2]

you know it always makes me wonder what steel I'm turning when it turns beautifully. The difference is really remarkable. Most of my metal (all?) is scrap, but I've found electric motor shafts to be some of the nicest turning steel I've experienced. No use to the OP, but thought it was worth commenting on

 

[G-ManBart]

My experience with 1018 is it basically it is harder to turn, let alone get a decent finish, the 8620 was much easier and also able to break the swarf. The 4130/4140 needed higher feed rate and DOC to get a decent finish and it was a rats nest of swarf. Have to push the cutting very hard to break the chips. The 8620 was much more manageable as to swarf and finish, turns easier then 1144 in my experience, and anything is better than 1018.

Boring 8620.
View attachment 416007

Thanks! I'm pretty certain the local large metal supplier has 8620 and I think they even have drops I can get pretty cheap. All I have on hand is either 1018, which I know is gummy, and then tool steel or alloy steel like 01, 02, 52100 and maybe some W1 or A2.

I just realized I have a buddy with a CNC plasma table so I think I'm going to see if I can't sketch the profile of a follow rest and get him to cut me a blank that I can machine for fingers, mounting holes, etc. As usual, one project leads to another!

 

[Jim F]

Let us know how the square thread turns out.
Seems MH doesn't cover it very much.

 

[Eddyde]

Why weld and not just remake the entire part?

 

[G-ManBart]

Let us know how the square thread turns out.
Seems MH doesn't cover it very much.

I'll do that. I'm not in a rush so I'll try to take pictures and document how things go. I may have to wind up grinding in clearance on the grooving inserts, or making a cutter out of HSS, etc and all of that might help someone down the road. If the metal supply shop has more than one kind of steel to try (someone mentioned A36) I'll probably grab some so I can do a comparison.

 

[G-ManBart]

Why weld and not just remake the entire part?

That's definitely a possibility, but would be a lot more work and wasted material. The spindle diameter is probably 2.5" so it would mean turning down 1.4" give or take. The spindle has a very large groove that would need to be cut, and a hole bored perpendicular for the handle, etc. If I can get a piece of 1.25" stock I don't have to remove much, and it will be less expensive than if I have to start with something twice that size.

I don't know when most vise companies changed over, but for many decades most bench vise spindle/screws have been friction welded. They would make the spindle as one part, the threaded screw as another part and then friction weld the two together. That was largely just to avoid having to remove so much metal to make them out of one part.

 

[G-ManBart]

Was able to stop by the metal supply shop and luckily they had a nice 3ft long drop of 1.25" diameter 8620...think it was like $25. I need about 16" for the screw, so I can mess up the first one and still have enough for a second attempt!

I also picked up some 1144 stress proof to make a handle for the same vise. A buddy of mine ran a shop making parts for vintage bench vises and was a retired too & die maker...he said 1144 was his choice for the handles because it was strong, turned pretty easily and had a touch of spring so you could lean on it and not permanently bend it. He made a couple of handles for me and I was very impressed with them.

It turns out the grooving inserts I bought, Kennametal NG3189R, have side clearance so we'll see how those work, and if I have to revert to HSS it shouldn't be an issue as I've got lots of blanks on hand.

 

[G-ManBart]

Delayed follow up to this thread. After getting everything source to make this I went to make a practice cut on mild steel...turned it to the major diameter and made my scratch pass. Uh oh....it seems I was wrong about the TPI. It's actually 3TPI, not the 4TPI I thought it was! My lathes both stop at 4TPI so I'm sort of stuck. It is an excuse to get that Precision Matthews 1660TL Ultra Precision lathe which goes down to 2TPI, right?

I gave the broken parts back to my buddy and he's going to reassemble the vise and see where the damaged section would be when the vise is fully closed. If it's forward of the nut (meaning never engages the nut) I'll probably bore pilot holes for a pin in both halves, assemble them with the pin keeping them in alignment, clamp the two halves in a vise using V blocks and then TIG weld the two halves together. After that I should be able to turn it down and hopefully make it presentable. We'll see...hopefully this is an option.

 

[Weldingrod1]

BTW. 8620 is hardenable... you may find your welds are crazy hard. I don't remember if it welds ok or not.

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