Member postings for john carruthers

Today my grandson and I spent a pleasant hour in the shed.
"Is a drill like a lathe grandad?"
Well, yes and no.
" how is it different then?"
"Well, a lathe turns the work against a fixed tool....sometimes...except when it doesn't...watch..."
"hmmm"
Then he went out to play in the mud and watch the hens...
(but you could see the wheels turning)

Beginnings are important times.

quick and dirty test for Pyrex, it has the same refractive index as many vegetable oils.
Immerse it and see if it disappears in the oil.

Hmm, shrinkage; as an apprentice I was working in the glass shop cutting glass for customers.
A gentleman came in with the usual bit of paper clutched in his hand and asked for a bit of picture glass which I cut, wrapped in newspaper and duly charged him for (all cash was handled in the office).
An hour later he was back, "you cut this wrong! it's too small".
I fished his paper from the tea chest we used as a bin and checked my size, all correct.
He went off in a huff. Another hour passed, the gentleman returned, this time clutching a fine boxwood and brass rule (you can see where this is going).
"I have been using this rule for 40 years, never had a problem" he proclaimed.
I offered it against the rule I had used to cut his glass and lo! the marks did not correspond. Upon closer inspection we discovered the legend "Shrinkage of Clay" embossed by the makers lozenge on his rule. He was correct, it had worked well in his shed but he'd never had to buy glass before.
He threw it on my bench and said, "You can keep that, I shall buy a standard rule".
and so for years it hung on the wall ready to wind up the unsuspecting, it now resides in my shed.

Hi Martin, I'm down the road in Port Talbot.

As a kid I would earn my pocket money by cleaning my old man's brass , an RM band sergeant, lots of blanco and brasso.
I used various bits of card cut to shape mainly to keep the brasso off me as the various badges all dismantled with split pins and plates behind, or unscrewed.
The pith helmet with its chin strap, Brunswick star and globe on top could take a morning
Picking out the cast brass lettering with a pin

1: First check the runout of the chuck register and also the interior spindle bore.
Meticulously clean the spindle and chuck threads.

2: Try swapping the jaws around into different slots, see which position gives least runout.

Even if you get it close with that diameter bar it may differ at other diameters.

3: get a 4 jaw chuck for critical work.

A 3 jaw scroll chuck may be better or worse, no guarantees.
A 4 jaw can be dialed in.

Clickspring uses one for clock wheels and frames.

It doesn't apply with your rubric, but a counter weight might simplify the working out?
Like a telescope drive.

As a plasterer's mate I used a few drops in a mixer load as a deflocculant to prevent the mix balling.
Mainly happened with dryish mixes like floor screed.
Never used it with concrete.

Hello Noonoo, I moved to Port Talbot a couple of years ago and have more or less organised my shed now.

Start the year as I mean to go on, mucked out the shed, made a mandrel to hold a set of mod1 gear cutters, made a couple of trial gears.

This sort of thing?

I've fitted many to boats, caravans, greenhouses etc....
toolstation stay

We would fit 'restrictor stays' as a safety option, mainly on tilt&turn windows on upper floors to avoid people falling through. They are a simple toothed bar that clips onto a stud.
They can be fitted to doors and would give some adjustment to how wide it opens.

Or, how about a damper style restrictor as used on caravans, boats, etc ?

Edited By john carruthers on 11/08/2020 08:56:27

We have used Oldham couplings for many years in telescope drives using steppers and VFO drives, never had a problem from the antarctic to the equator.
Even using software and encoders to cancel backlash, scope drives are very sensitive to drift as any astrophotographer will tell you where mili arcsec pointing is the goal.

For testing I use either a plastic pipe from the coffee machine steam outlet, or a hand pumped garden sprayer.
An old fridge compressor could be pressed into service?

Ingals ATM vol 3 page 35 >

I have them in pdf if you need them.

Edited By john carruthers on 27/04/2020 18:37:01

mini saw blades

Try your local car dealership, they use a UV bond for attaching rear view mirrors to windscreens.
You could use high modulus silicone mastic but in both cases try to avoid contamination with silicon furniture polish. It is tenacious stuff.

I ordered a set of mini saw blades (like slitting saws) from a Chinese supplier on xmas day, they arrived yesterday so I roughed out a 'scape wheel for the clock..

Have you tried high modulus silicone sealant? squirt it into the rings, let it set off.
Lightly grease any parts you don't want stuck.