And Now for the Twin

[Mike Rometer]

DT, worry ye not, I intend to Loc-tite and cross-pin on final assembly.

To accurately mark the piston rod centre onto the Cross-head, I use this method.

First produce a centre to fit in the bore of the bottom cover and harden it.

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Place in the centre in the bore and slide the Cross-head sharply down on it.

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I was pleased to see my original marking out was exceedingly close.

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[Mike Rometer]

Simple enough to set the Cross-head in the 4-jaw and centre on the pop-mark, checking also that it is sitting square in the jaws with a try-square off the bed.

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All re-assembled ready now to cut the piston rods to length.

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[DetroiTug]

That looks like it worked really well

[Mike Rometer]

I've used that method a few times now. The proof of the pudding is when the rods are on - and running in the bores!

[DetroiTug]

I'll bet the alignment is perfect. Same way headstock and tailstock centers are aligned and set over adjusted on the lathe bed.

[Mike Rometer]

A few bits and pieces have been done under difficulties. To wit, I broke my favourite pair a w/shop specs, and have had to make do with a secondary pair which don't suit close work nearly as well, and I have to wait nearly another fortnight for an Ophthalmologist appointment. This virus has a lot to answer for!!!

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Bearing in mind the comment about rods maybe coming loose and the difficulties of re-tightening them, I added some spanner flats to the piston-rods. They also aid assembly. The woolly thread (pic) had yet to be run with a die to clean up. S/steel (drill rod) doesn't thread well at slow speed (or at high speed sometimes! ). I usually don't run as deep as this and give the die a little more work to do. I also added the small grub-screw as a retainer.

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Whilst messing, I added some 'pockets to the Cross-heads for the gland studs/nuts.

So far everything seems right for the 'stroke' except one small item, I think I need to reduce the length of the buttresses on the Cross-head Slippers a touch, just for peace of mind, they don't seem to touch, but are quite close. One must allow a little for expansion!

Only one other comment - it all seems very tight!

(Note the white stuff on the ground outside, quite a rarity in recent years, this year we've had more than we want!)

[RNoe]

Nice work, Mike.
And that white stuff on the ground outside makes it easier to "justify" working in our shops!
RussN

[Mike Rometer]

Thanks Russ.

I'm still working under difficulties, new specs due any day! Whilst I've not been totally idle progress seems slow.

As light relief I made the parts for some right-angle fittings for wick feed oilers to the Cross-Heads. The flip top oilers I usually keep in stock, but they are not wick fed so have to be modified with a riser tube and wick, a simple task when you can see what you are doing (and have three hands!).

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Two pieces silver soldered.

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Corners rounded and fitted, backing plates drilled and tapped.

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[Mike Rometer]

I've also cut the material for the six pillars, and turned and threaded the ends.

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These are fairly chunky but will need to be 'prettied' up so that will reduce them some. The final shape still alludes me, so they may finish up reasonably simple rather than very fancy. When all said and done, Pretty doesn't make it run any better.

[TriangleTom]

Beautiful work as always. Really exciting seeing the whole thing come together.