Member postings for john carruthers

The flexy cable drive wasn't so good, first load applied and it writhed about like a constrictor, ok for small drilling and polishing maybe.
Luckily I found a discarded sewing machine in a layby and now have the motor from that driving the spindle via a belt.

I'm making better progress now all is secure, the wheels look right.
Made the escapement wheels and hub yesterday, looks like arbours and lantern pinions today.

I use a bit of 10mm float (glass) and wet'n'dry paper of various grades. Spray on carpet adhesive is handy to keep it flat and stop it slipping about. (maybe double sided tape?)
If it's going to be blued I then use some of my old mirror grinding grits and tin oxide or rouge on the glass for the final polish.

I've seen the flooring guys level high spots with 'bears', big old grind stones the size of breeze blocks. Attack the lump from all sides with plenty of water to keep the dust down and clear the grindstone pores.

All done with machines now and a smear of compo.

It could be held in a 'sink' ?
- a shallow socket turned in a blank then the gear shellaced or super glued in?
Or, depending on what operation you are performing, just glued to a face plate?

A mate has a similar machine he aqcuired from a school sell off.
It sort of worked when he got it but had similar problems getting the column orthogonal to the table.
He could get it right when static but any load on the quill tipped the column back a tad.
We shimmed it, one thickness of coke can and one of 'pie dish' ally foil under the column bracket was sufficient to give a decent finish.

I found treasure in great store, 1/8" brass plate, 28mm dia bronze bar....

I then started rigging a flexy drive from the drill press to a tool post drill and thought ' this would be a better drive solution for the flycutter spindle' .
So I know what I'm doing today.

Click and spring roughed out, needs some better blued cheesehead screws and the spring hardened.

'Experience'
"what life gives you just after you need it".



Off to the scrap yard today to have a root around. Wonder what treasure I'll find ?

I bodged up a file in a drill post to keep it square and just worked it up and down to put a key way in a pulley. Took a long time but it worked.

Made the 80T wheel yesterday but there was a tiny touch of 'flat' left on the tips. I went over it again taking just a hair off, but, the fly cutter must have slipped a bit and destroyed a tooth. Lesson learned, I shall make a stop to keep the cutter square then try again.
At least the blank will come in for a smaller wheel.

Preparing to cut the first wheel (80 T mod1).
They do ring, like an old fashioned door bell or phone..

I like that, is it your own design?

I spent an hour making a tiny 2 arm bearing puller, well worth the time. Now it's made I use it frequently for pulling spur gears from telescope mount motors and worm shafts, as well as bearings.

Have you tried cycles of freezing/heating it? The different coefficients of expansion may help loosen the brass?

I've seen a couple of old lathes that use a Sturmey Archer 3 speed hub as a back gear ?

I had a go at the main arbor today, and my first attempt at 'burnishing'. I use an old 1/2" chisel rubbed sideways on a stone to put a 'grain' on it then press it hard onto the work in the lathe with a bit of spit. It's very satisfying to see the shine take across the bearing suface, still a few faint turning lines showing up in the photos

It used to be quite common for amteur telescope makers to produce their own worms and wheels.
Traditionally you make the worm leaving plenty to produce a hob at one end wich is later discarded.

**LINK**

For a Herschel wedge the angle only needs to be small, say 5 deg, and the rear face can just be left ground so any plane surface can be used. I had an old quartz plano convex lens I flattened the back off a bit and used the flat, with a heavy ND and an adjustable polarising pair it gives a good sharp image.
I use a bit of tin plate to reflect the unwanted energy to a heatsink (saves anyone peering up the exhaust )
I have seen old bino prisms used off the hypotenuse and the other faces ground. Ideally it needs one further reflection but heavy weders glass after the prism can attenuate the light enough.

The Mk 1 depthing tool.
I shall fit a screw adjuster to make life easier,

I played with A series engines and had a lot of fun squeezing every ounce out of them, but in the end found it easier to slip in a B series (Marina 1800 TC for choice).
An all synchro box and a Riley 1.5 diff helped the ratios, and made for a reasonably quick Minor 1000.
I used the discs off the Marina and Riley drums on the back. A direct servo off a Rover sd1 made it stop better.
lowered all round, telescopic dampers, and an anti roll bar. The major improvement was good tyres, Avons changed it completely.
Apart from being an inch or so lower it didn't look any different.
Some worried Ford SR guys round our way

I found a small motor so now I just need a stretchy belt ~ 12" circumference / 3.8" dia.