Stainless steel machining

[KompetentKrew]

Hello,

I need a pin machined from 316 stainless steel. It needs to be turned from square or hexagon cross-section bar, so that I can get a wrench on it, the 5mm length in the middle of the below diagram; and the butt end of the pin needs to have an 8mm thread on it. The pin itself is 9.45mm in diameter.

I hope this description, with the diagram below, makes sense.

Questions:

1. Who would you recommend for a job like this? I'll need them to post it to me, I'm afraid.

2. How much would you expect to pay?

Thanks.

 

[Rhylsailer99]

I have a myford super 7 lathe and a Coventry die head with m8 dies.
Turning stainless is my thing as I make lugworm pumps for my sea fishing shop. I'll have a look I might have some stainless hex. Bar in .

 

[Rhylsailer99]

A4 316 Stainless Steel Bar Hexagon 8mm To 50mm Cut To Length *** | eBay


I think 13mm would be ok to turn down

 

[Rhylsailer99]

M8 1.25 is that correct

 

[KompetentKrew]

Yes, 13mm would be perfect @Rhylsailer, as then I could just put a standard M8 nut on it, which also takes a 13mm spanner.

I think M8 1.25 is right - just the standard 8mm diameter nut / bolt you get at the chandler.

Could you PM me prices to make one and two of these? A spare would be nice, but it's not essential.

 

[rotrax]

Why not just have a bored hole through the end?

Then use a small screwdriver as a tommy bar.

Make it from a 10 or 12mm X 55 S/S bolt

My twopennyworth anyway...........................

One of my old racing sponsors - the man who invented pub optics - often told me " An Engineer is a man who can make for a tanner what anyone else pays a quid for! "

 

[rogerthebodger]

Turning Stainless steel from a square or hex bar is a pig as it chips carbide tools and HSS tools wear out too quick.

You couls also take a standard M8 setscrew and weld the 10mm dia by 25 long bar onto the head then just turn that down to the 9.45 dia section.

 

[KompetentKrew]

Why not just have a bored hole through the end?

Then use a small screwdriver as a tommy bar.

Make it from a 10 or 12mm X 55 S/S bolt

That's a good suggestion - I think it needs to be wider at that point, to clamp down on it properly, but that's all.

 

[KompetentKrew]

Turning Stainless steel from a square or hex bar is a pig as it chips carbide tools and HSS tools wear out too quick.

Thanks, I didn't know that.

You couls also take a standard M8 setscrew and weld the 10mm dia by 25 long bar onto the head then just turn that down to the 9.45 dia section.

Yes, I think that would do fine, too. The pin does not need to be exactly centred. Needs to be a bolt not a setscrew, though, as I think that shoulder is desirable to clamp down on. There's a fair bit of load (it's part of the tiller pilot).

EDIT: are there two definitions of "set screw"?

• Cromwell Tools - Experts in Hand Tools, Power Tools and PPE
• Plain Stainless Steel Hex M10 x 20mm Set Screw | RS Components

 

[KompetentKrew]

My twopennyworth anyway...........................

One of my old racing sponsors - the man who invented pub optics - often told me " An Engineer is a man who can make for a tanner what anyone else pays a quid for! "

Thinking about this, I should probably just drill out the hole a little larger and then turn down a bolt (or setscrew - see last edit).

It appears the smallest metric standard bolt that would work would be an M12 - to accommodate a 9.45mm pin I need a bolt with a d3 size larger than that, I think?

 

[Rhylsailer99]

Turning Stainless steel from a square or hex bar is a pig as it chips carbide tools and HSS tools wear out too quick.

You couls also take a standard M8 setscrew and weld the 10mm dia by 25 long bar onto the head then just turn that down to the 9.45 dia section.

I done it it does knock the tool.a bit but I use a heavy duty hss tool never carbide on hex it would destroy the tip.

 

[Rhylsailer99]

A4 316 Stainless Steel Bar Hexagon 8mm To 50mm Cut To Length *** | eBay


I think 13mm would be ok to turn down

If you buy a 100mm in 13mm and post it to my shop pensarn tackle bait, 40 Marine Road ll22 7pr. I'll knock it up for free and you just pay return postage.

 

[Graham_Wright]

it would destroy the tip.

That's a new one on me! I have just produced almost exactly what is required here (fitting an ammeter to myMGB V8 which required a stud extension).
I machine stainless frequently round, hex and occasionally square. Not a nice noise on the second two but no insert breakages with a modicum of care.

 

[Norman_E]

I would turn it from round bar, and mill the flats for the spanner, or even just file them.

 

[DinghyMan]

That's a new one on me! I have just produced almost exactly what is required here (fitting an ammeter to my MGB V8 which required a stud extension).
I machine stainless frequently round, hex and occasionally square. Not a nice noise on the second two but no insert breakages with a modicum of care.

Same here, we almost exclusively use inserts and have no problem machining 303, 304, 316, and Duplex grades of hex and square stainless as well as on stainless welds and odd shaped stainless built-up parts, all very interrupted cuts
Often use very high positive rake polished inserts with very thin edges meant for aluminium on hex and square with no issues, cant remember when I last used non-insert tooling
Lack of rigidity may break inserts but interrupted cuts wont