Hello and a part-built blowfly

[racinjason]

Lisa,
I hold the workshop vacuum near the tool while machining that then makes it a pleasure to work with iron.
cheers Jason.

[Lisa]

A quick shot of the setup for machining the bottom (and top) faces (though as the steam chests are side-on between the frames, I suppose they're really the side faces).


Using a quoin inside the cavity, so as to not accidentally crush the casting; while I've never seen this happen, it's a possibility best avoided.

[rrmrd66]

Hi Lisa

Just about to do the same on my Hunslet

Please explain what is a "quoin" and what it does?

Regards

Malcolm

[Jim]

You're doing a cracking job on the steam chests Lisa. Must ay i like the pink cover to the lathe's gear box and motor. 

Jim

[Lisa]

Jun 14, 2018 6:35:58 GMT rrmrd66 said:

Hi Lisa

Just about to do the same on my Hunslet

Please explain what is a "quoin" and what it does?

Regards

Malcolm

Hi Malcolm, there's a spare quoin sitting on the compound slide in the above picture, so you can see it clearly. Essentially it's an expanding block, turn the screw and the extension expands out, allowing for clamping between two fixed points, or supporting the inside of a steam chest. Mine are from the remnants of a set of letterpress printing setup from dad's last print shop (his trade), they expand from about 17mm to about 25mm; though there's other sizes available. They were used to lock a line of type into a letterpress frame, for printing. If you look around online you can still find them for not much at all; Letterpress printing still has a hobbyist and historical following.
Also, as a bit of luck, the chuck key for my 4-jaw fits the quoin perfectly!

Jun 14, 2018 6:43:39 GMT Jim said:

You're doing a cracking job on the steam chests Lisa. Must ay i like the pink cover to the lathe's gear box and motor. 
Jim

Thanks Jim; the cover's actually red, but the light makes it a bit prettier

[Lisa]

So that's both steam chests machined to width and height now.

[rrmrd66]

Hi Lisa

Ref Printers Quoins

Well, well, well.

You live and learn.

Of course now you told me, the internet seems to be flooded with (printers) quoins!

Are they, within their max/min range, infinitely variable? The teeth look a bit "ratchety" (sorry for that technical term).😀

Cheers

Malcolm

PS. Nice job, BTW.

[Lisa]

Hi Malcolm,

They are infinitely adjustable (within their range); the screw adjusts an angled slide that pushes the extension out. There's plenty of different designs by different makers, but they're all essentially the same inside; slide two triangles together and the height changes.
You do however want the 'modern' type, which are self-contained little units, rather than the old kind that were just two triangles with teeth.
This mob list a few makes of 'modern' type: ddmetalproducts.co.uk/product/letterpressquoins/

[rrmrd66]

Hi Lisa

Thanks for that. I will check it out.

Did you by any chance see the below in the Tools section?

modeleng.proboards.com/thread/12529/machinists-toolmakers-jacks?page=2

Regards

Malcolm

[Lisa]

I figured as the 4-jaw was currently set right for holding something that size, I might as well get the steam chest covers machined to thickness:



Only one done so far, I'll machine the edges to size in the mill at some point.

[simplyloco]

Good to see a 4-jaw being used as it should be instead of using a mill!
John

[Lisa]

It's easier to do a lot of it on the lathe anyway John; unless you've got a face cutter big enough to do it one pass at least!

[Lisa]

A little time in the workshop today sees one rear cylinder cover almost complete, just needs the slidebar fixing hole drilled and tapped.

[Lisa]

That's the other steam chest cover machined to thickness; getting there a bit at a time.

[Lisa]

Just did a little bit today, as my back's been shot again lately. Got a steam chest set up in the lathe, and made a few cuts on the end; there's still a little over 2mm to come off this end.
However at this point I sneezed, and my back spasmed, so I decided to rest for the day.


If I'd remembered I'd have slipped some thin aluminium between the job and the chuck jaws, to prevent any marks/damage, oh well. Still trying to decide if I'll just file the insides clean, or get fancy and clean them up on the mill.

[Lisa]

Got some time in the workshop today, and got a few things done, or at least started.
So I finished the front of one steam chest to size, just the rear with the gland on it to do for this one.

Also visible is the ports marked out on the cylinders, the black is just to make thing obvious, the scribe lines are such that all the ports are correctly positioned but undersize; thus 'do not take the line off without measuring'.

The other steam chest's about half way to the same point.


So then I centred the second rear cylinder cover on the rotary table, ready for machining the outside of the gland, the slidebar support, and drilling the bolting holes.

Also shortened that bolt a little, rather than putting a nut under the head, as I'd had some interesting clearance wangles on the first one that I wanted to avoid this time.
Speaking of the first one, I realised that all the holes in it are in the wrong place. Just me messing up some maths, so they're all ¼ of a degree too far clockwise; it's barely noticeable, so I'm just going to pretend that didn't happen and drill the cylinder to suit.

[stevep]

I reckon I could live with a 1/4 degree error!

[rrmrd66]

Hi Lisa

Beware the bottom end cover clearance hole at "6 o'clock" coinciding with the drain cock tapping!

See my last Hunslet post.

Cheers

Malcolm

[Lisa]

Jul 8, 2018 9:39:00 GMT stevep said:

I reckon I could live with a 1/4 degree error!

Just what I thought; still annoying though.

Jul 8, 2018 9:49:43 GMT rrmrd66 said:

Hi Lisa
Beware the bottom end cover clearance hole at "6 o'clock" coinciding with the drain cock tapping!

Thanks Malcolm, I saw that on your hunslet post; fortunately not an issue with Blowfly, as the holes are spaced at 45 degrees, offset by 22.5 (not 22.25!) degrees, so they're clear of everything.

[Lisa]

Some filing and fiddling got me a centre pop in the right place for drilling the steam chest gland. Then came time to set it up in the lathe and the 4-jaw started to eat itself again; I'll get a new (better quality, and possibly bigger) chuck when I can afford to, but for now I'll just have to strip it down again, and try to get the one bad jaw back in working order.


Then I thought I'd give it a go in the Taig lathe; the casting hangs out of the chuck rather alarmingly, but it's cutting fine. Once I get the face to size, and the outside of the gland protrusion round and to size I can put the steady on it while drilling/machining the gland itself. I suppose I could centre drill it and support it with a centre for now, but not entirely sure it's necessary.