valve stem turning

[bluejets]

Saw a video from Joe Pieczynski about turning ultra small diameters in one bite and thought useful for turning valve stems.

Current approach is to whittle down to size with small amounts of overhang in a series of "moves", extending the raw material perhaps 3mm each time.

Takes a long time per valve stem, so asked about the tool he used which appears to be no longer made.

Query would be, any details available on the holder/tool bit setup so one could "copy" or make one's own tool to enable this operation.

As might be evident, many of the tools quoted at times are simply not available down in Australia, or are extremely costly to procure.

 

[mu38&Bg#]

This is really about cutter geometry. Taking a large depth of cut while maintaining low cutting force requires high rake and sharp edges. Plenty of inserts fit this requirement, or grind your own. That video was cutting aluminum which is easy as pie. Steel or stainless is more tricky, and I wouldn't try without oil. Machine and setup should be rigid.

 

[bluejets]

No, it was stainless steel.

1/2" diameter 303 stainless AND he used Tap Magic for stainless cutting oil.

 

[Drawfiler]

I turn long small diameters using a travelling steady, another way is to use a twin or balanced tool setup with two cutters of the same geometry mounted in a holder opposing each other across the diameter so the push off from one tool is balanced by the other. The tool. Holder is easy to make and can be uses with small brazed on tooling or HSS.
The other production way is to use a roller box, these are difficult to set up and tips hard to find but you can grind HSS cutters with care.
Taking these large cuts need a strong machine as the cutting forces are considerable.

 

[mu38&Bg#]

No, it was stainless steel.

1/2" diameter 303 stainless AND he used Tap Magic for stainless cutting oil.

OK, I watched it when he posted it years ago. Doesn't change anything.

 

[jkimberln]

Do a Google search on "hollow Mill". Then make one to suit your needs from drill rod or silver steel, and heat treat it. Basically just a hole of the correct final diameter with milling cutter flutes on the end. In use, go slow with lubrication.

 

[l.dullum]

Model Engine Builder magazine issue #7 had a build article on a valve machining jig that formed valve stems in one bite. I made a similar "box tool" to do the job with great success.

 

[GreenTwin]

I can't find the video now, but someone has a video where they make the stem from ground stainless rod, and the top of the valve from class 40 gray iron. The top of the valve is beveled slightly, the rod inserted into the head, the top of the rod heated red hot with an oxy-acetylene torch, and then the rod is peened to fill the bevel.
Makes for a very nice valve, with a very accurate ground stem.
I will have to look for that video.
I intend to copy whoever's method this is.

.

 

[wespete66]

and then the rod is peened to fill the bevel.

This method is not uncommon amongst those who rebuild the old stationary engines (hit & miss), where the valves are not available anywhere in correct sizes.

 

[DKGrimm]

A friend, Dave Berry, told me about this approach, so I made half the valves for my homebrew 4-cyl this way and half using 303 heads silver soldered to drill rod stems. I used a larger tip radius cutter to get a nice fillet under the head, and it worked just fine, except that the surface finish on the stem was way too rough to use directly. I had to make an external lap to finish the stems. I can't find a picture of a one-piece valve made this way, but here's a picture of the composite version of the valve.

 

[PeterDRG]

Do a Google search on "hollow Mill". Then make one to suit your needs from drill rod or silver steel, and heat treat it. Basically just a hole of the correct final diameter with milling cutter flutes on the end. In use, go slow with lubrication.

Sometimes known as Running Down Cutters. Dormer used to make some.

 

[ranger]

Here’s a kit I bought some years ago, haven’t got around to using it yet. Bought, I think, from ”Chronos” in Dunstable.

 

[PeterDRG]

Looks like a JABUS Small Diameter Turning Tool. You bore the phosphor Bronze plug to suit the job. They were supplied with a selection of blanks.

 

[dcurl451]

Looks like a JABUS Small Diameter Turning Tool. You bore the phosphor Bronze plug to suit the job. They were supplied with a selection of blanks.

That's a JABUS tool alright, only a variation on a theme, that time by my friend John Anning. Just like a capstan roller box, they're a complete pig to set!

The principle is obvious, and you could easily make one in an afternoon. If I were to make another, though, I would make a series of hardened steel bushes for the material to pass through, mounted in a cassette bearing. The bronze bushes of the JABUS do wear, and then you have to set up from scratch again.

-Andrew UK

 

[PeterDRG]

When did you last talk to John ? I used to know him well 20 years ago. I left him a message in Linked In, but haven´t heard back.