Member postings for john carruthers

24 hours later and the sc3 lathe is running again>
The parts arrived this morning and were a simple fit. I did put a brass strip on to hold the half nut gib instead of those p*** poor washers.

I still don't own any 'proper' parallels, I use old bearing races (quite accurate) and bits of drill rod, must get some.

I found some little coasters made from squares of black granite on Tesco's 'reduced' shelf, 50p, make excellent plinths.

Looking good. I had similar problems chucking parts until I made a back stop for the spindle.

Made a start on a replacement gearbox axle for the wheelchair. The original is nylon and it keeps shearing off so I started one in brass. Cutting an 0.8mm thread when my shiny new sc3 lathe half nut started 'skipping' so it was cutting grooves not a thread, most annoying.
I got on the Arceurotrade who promptly called me back could not have been more helpful.
We thought of a few work arounds, but in the end agreed a pair of half nuts instead of the single nut was the way to go.
The necessary parts are in the post, gratis, so the chair may get a permanent fix.

are you buying or making the beam splitter?

To hold the front screen in a Lightning we used a 2 part polysulphide, it would bond glass/ally and ally/ally, not cheap though.

Thank you gentlemen, I found PLAN but not the constant and was wondering why the HP value was so high.

The little Flexispeed could run on a nominal 1/4 HP electric motor but I'd like to see it run on steam.
Also I'd like to build an engine that can do useful work so I'm looking around.

Sorry if this has been asked before but what sort of power output would a Stuart Victoria (single) engine produce and at what pressue?

My daughter now lives within walking distance of Kempton steam museum, and her partner has taken up home brewing; so all is right with my world

this took me to a viewing page which I then downloaded;

https://ia801408.us.archive.org/27/items/whitworthmeasur00whitgoog/whitworthmeasur00whitgoog.pdf

New sc3 lathe is mostly ready for action; slides rubbed up and brass gibs fitted, new Timken TR bearings, all set up straight level and square. Sharp edges on the castings lightly broken with a fine stone, feed screw collars skimmed to reduce end float, lead screw bearings bushed with bronze and oil ways attended to.
Just needs a TDI and the other half nut. I will get a milling slide for it once a carriage lock has been fitted.
Made a few experimental threads and all seems well

Now waiting for a small casting kit.

Edited By john carruthers on 30/06/2015 07:45:04

Collimation, now there's a minefield

I agree with Neil, the collimator should be of a similar fit in the drawtube as the eyepieces. And yes, all the tools in the world will only get you close, the star image is the final arbiter.
I tested my Barlowed set up in the lathe and found a massive pointing error in the lens stack so take nothing for granted. I also turned the collar off the comercially made collimator as it didn't sitting true with the draw tube axis.

Had to do the diagonal on the 28" refractor at Greenwich some years back. Over 28 feet the beam was initially 4" off centre

At last, the lathe fairy came in the night.
An SC3 from Arceuro.

Spent the morning degreasing and fettling.

Edited By john carruthers on 25/06/2015 14:29:50

Yesterday we visited my wife's 'old uncle Bern', a retired fitter of the old school. Sadly he is setting his afairs in order and generously gave me some of his old tools. A very personal bit of kit were his Snap-On 4" files, c1970 made by Nicholson, he used them every day of his working life but like him, they are still keen.

Then when I got home a new Grobet 8" #2 file had arrived. I shall definately be buying more of those

Also today; "something crated this way comes"

Good system with little or no belt stretch, and you can specify reduced backlash pulleys.
More and more we are seeing toothed belts/pulleys in telescope mounts where sub arc second pointing and periodic error are required.
There are several firms supplying after sales upgrade kits for the mass produced Asian mounts, and a few guys in sheds doing bespoke work to bring Victorian heritage instruments up to scratch.

Edited By john carruthers on 25/06/2015 07:52:09

Yesterday evening the woebegone young lad from over the road brought in his Golf cylinder head.

(ally head + exhaust stud) * (young lad + big spanner) =

Drilled out the sheared stud, drilled, tapped oversize M10 to take a liner. Tapped that to M8 so he can use standard studs.

Slow it down for any interupted cut, minimum tool overhang (without fouling the chuck).
To get a feel for it try facing off a bit of rectangular scrap, you'll soon find a comfortable speed/feed. You soon get used to the "chonk - chonk- chonk " noises.

Snap! almost exactly what I shall be doing later.
I shall reverse the jaws in the 4 jaw chuck, pop the wheel in and centre it up, then take a few slow cuts.

for hardened padlocks I cannot recomend the 'inox' type thin cutting discs highly enough. A friend keeps losing keys and I regularly cut the old locks off for him. A battery angle grinder and a 1mm disc; like the Wehrmacht through Luxembourg.

I ground a TCT masonry drill to 90 deg and use it dead slow, so far so good. I have used it in a hand brace but obviously wouldn't recomend that for hundreds of holes.