The launch engine is a little bigger than the OCLE that Caldwell and Edelstaal sold in the 1970s. Also the main bearing and valve have changed places.

Cary

Hi Richard,

If you do get stuck on this one silly detail, give me a shout. I have access to a range of machines and if necessary can cut the size you need from something bigger - or at least have a good try at it!

Regards,

Keith? s. Angus,

In Slough

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Hi Gang:

How about 7BA threaded rod ( 316?) with 2.5mm tubing cut to length over it?

Carl.

?

Hi Richard,

Thinking that LBSC would not have specified metric rod (?) would 3/32" be OK?

You might need to re-make the mating part, of course! ? 3/32" was often threaded 7BA by LBSC (though it is a fraction small) and 303 stainless will be much easier to thread than 316 grade!?? I have used 7BA on 3/32 stainless for studs on the steam chests of my big 3.5" gauge loco (28 bore x 50 stroke) with every satisfaction.

3/32" stainless in 303 is available from Macc Model Engineers and several other suppliers.

Hope that helps?

Regards,? Richard.

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Here is the McMaster link:

?

On reflection, in the short term,? perhaps I should seek a UK based retailer of a small length of 2.5mm dia grade 316 st. st.!!

(I do not think the Unimat SL would be very happy with big cuts owing to it's general lack of mass and rigidity while the manufacture of the steady will become a project in it's self - I will have to get the iron casting made and jig bored to accept the extended cross slide bars by others.)?

Richard?

On Thursday, 28 February 2019, 17:42:53 GMT, mdupreno1@... [UNIMAT] wrote:

?

Good points, Keith.

Since the length is only 1/2", seems like it could be turned from a larger diameter piece held only in the 3-jaw chuck. In this case, the threads on each end would be best done with the thread chasing attachment, if available, instead of die. The 52 TPI and .5 mm might be close enough, for 1/8" thread length.

Martin P.

-----Original Message-----
From: ksangus@... [UNIMAT]

?

The traditional way to do long thin items is to turn them down in one cut, so the thin section is never exposed to cutting forces. Large finishing cuts are difficult on the Unimat, so I would experiment with making the last cut as deep as possible, while starting from a larger diameter bar that won't flex when cutting. This will mean playing with toolbit angles to get the best performance, and I'm not sure what to suggest there.

A lot depends on the grade of stainless you're using - there is a wide range of machinability. That in turn leads to the question of why stainless? Would any other alloy be usable? I was at a show a few weeks ago where one exhibitor claimed that the titanium he was selling machined more freely than most grades of stainless - but he was the salesman.

And then finally why turn down to the size when you can buy precision drawn, or ground, stainless rod? The 3 mm and 1/8" sizes I used to get in 316 were almost polished, and made to a very tight tolerance. I've just found some 2.5 mm 316 in short lengths with a tolerance of +0.0/-0.006 mm.

Keith

---In UNIMAT@..., wrote :

Hello,

? ? ? ?I have need to produce a 2.5mm x12.7mm long item from stainless steel with a GOOD FINISH (it will also have a 7BA x1/8" thread at each end).? The first attempt was junk! with a form and finish best described as looking like a leg for a Windsor? chair from a doll's house.? The second attempt seems to be more promising-with very light cuts (approx 0.02mm , slow feed and very high spindle speed)? A lot of the problem seems to be a lack of support and to this end I have started to make a wooden pattern for a traveling steady, to be mounted on extended cross slide bars; in view of the small size of these machines and their resulting use for very light work such as described, I find it surprising that a TRAVELING?steady has apparently never been available as an accessory.? I would be pleased to hear the views of others on this topic.

Regards

RICHARD PENDER

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Hello Richard:

McMaster-Carr has 316 stainless wire in 0.102" diameter, 0.09mm over 2.5mm.

Perhaps you could grind this to size. Grinding has less force against the part than a single point tool. Plus you would have a ground surface!

While some would call me a cheat, I avoid threading. I would put set screws in each end of this part for the threads.

Carl.

?

On reflection, in the short term,? perhaps I should seek a UK based retailer of a small length of 2.5mm dia grade 316 st. st.!!

(I do not think the Unimat SL would be very happy with big cuts owing to it's general lack of mass and rigidity while the manufacture of the steady will become a project in it's self - I will have to get the iron casting made and jig bored to accept the extended cross slide bars by others.)?

Richard?

On Thursday, 28 February 2019, 17:42:53 GMT, mdupreno1@... [UNIMAT] wrote:

?

Good points, Keith.

Since the length is only 1/2", seems like it could be turned from a larger diameter piece held only in the 3-jaw chuck. In this case, the threads on each end would be best done with the thread chasing attachment, if available, instead of die. The 52 TPI and .5 mm might be close enough, for 1/8" thread length.

Martin P.

-----Original Message-----
From: ksangus@... [UNIMAT]

?

The traditional way to do long thin items is to turn them down in one cut, so the thin section is never exposed to cutting forces. Large finishing cuts are difficult on the Unimat, so I would experiment with making the last cut as deep as possible, while starting from a larger diameter bar that won't flex when cutting. This will mean playing with toolbit angles to get the best performance, and I'm not sure what to suggest there.

A lot depends on the grade of stainless you're using - there is a wide range of machinability. That in turn leads to the question of why stainless? Would any other alloy be usable? I was at a show a few weeks ago where one exhibitor claimed that the titanium he was selling machined more freely than most grades of stainless - but he was the salesman.

And then finally why turn down to the size when you can buy precision drawn, or ground, stainless rod? The 3 mm and 1/8" sizes I used to get in 316 were almost polished, and made to a very tight tolerance. I've just found some 2.5 mm 316 in short lengths with a tolerance of +0.0/-0.006 mm.

Keith

---In UNIMAT@..., wrote :

Hello,

? ? ? ?I have need to produce a 2.5mm x12.7mm long item from stainless steel with a GOOD FINISH (it will also have a 7BA x1/8" thread at each end).? The first attempt was junk! with a form and finish best described as looking like a leg for a Windsor? chair from a doll's house.? The second attempt seems to be more promising-with very light cuts (approx 0.02mm , slow feed and very high spindle speed)? A lot of the problem seems to be a lack of support and to this end I have started to make a wooden pattern for a traveling steady, to be mounted on extended cross slide bars; in view of the small size of these machines and their resulting use for very light work such as described, I find it surprising that a TRAVELING?steady has apparently never been available as an accessory.? I would be pleased to hear the views of others on this topic.

Regards

RICHARD PENDER