Member postings for Peter Cook 6

Another +1 for MoI. I don't have a technical drawing background and found my brain simply did not get on with the "standard" CAD software paradigms.

MoI I found very easy and intuitive, and is excellent for creating models for 3D printing. I do use blowlamp's approach (PDF's) to produce hard copy to take to the workshop, but I only draw on the dimensions I want rather than producing formal third angle drawings - which I struggle to read anyway.

You could be looking for 10-32 square nuts and bolts

10-32 square nuts are 9.525mm across flats ( 3/8" ) and 3.3mm ( 0.13" ) thick. 10-32 bolts are 3/16″ (4.76 mm) diameter.

Those are the sizes used on my Taig lathe and I think Sherline use the same ones.

Accu carry both bolts and nuts in stainless.

edited to remove emojiis

Edited By Peter Cook 6 on 15/04/2023 16:08:55

Edited By Peter Cook 6 on 15/04/2023 16:09:56

Have consideration for future repair persons!

In 50-100 years when time, muck and corrosion have stuck the screws in firmly, really hard screws are more likely to break when being removed.

I don't think hardness has much bearing on the quality of the shine, in fact too hard might even prevent the polishing process from removing the imperfections. Think about the shine you can get on silver.

Go with Daniels you won't go far wrong!

At soft solder temperature I would not have thought you would make much difference to the temper. At silver solder temperatures you might be losing hardness, but then how hard were the original palets?

I suspect spring steel is a lot harder than the palets were originally.

Edited By Peter Cook 6 on 07/04/2023 20:52:55

Bernard - idea stolen from Taig Micro Lathe Tool Posts, Boring Bars & Locking Levers (micro-machine-shop.com)

In the US you can buy 10-32 handles, but they are unobtanium over here. I use a length of 10-32 studding Loctited into M5 female handles which are easy to get (& cheap) from Ebay.

To answer the original question about Taig Toolposts. The rear toolpost is different. This is a quick shot of three of mine.

Centre height from the cross slide is 31mm

On the right is a standard Taig Toolpost 45mm high, bottom of slot is 25mm from base. Top of 6mm Tool sits on centre height.

In the centre is a Taig Rear Toolpost with the tool mounted upside down. Overall height 51mm, bottom of slot is 31mm up from base - so inverted the tool sits on centre height.

On the left for completeness is a Taig rear mounting parting toolpost that uses a T shaped blade. The holder is inclined so that the blade can be set on centre height.

Hope this helps

The ones I use a lot get the handles as seen on the right. The less commonly used rely on the standard cap screw.

Sorry - didn't see Bernard's response!

Edited By Peter Cook 6 on 23/03/2023 14:37:33

When I had new windows fitted to the house a few years ago, they were powder coated aluminium frames.

I was supplied with some touch up paint should it be needed. The paint appears to be a two part epoxy - the instructions say mix 4:1 paint to what I take to be a hardener. There is no information beyond the colour, the mix instructions, the usual safety warnings and some part numbers which appear to be based on the window suppliers order number.

A call to your local powder coating firm might elicit some information on touch up paint.

PS an online search for "powder coating touch up" gets lots of hits

Edited By Peter Cook 6 on 13/03/2023 14:05:50

See Front Seat Heating | BMW UK for an example!! £15/month, £150/year, £250/2 years or £350 unlimited(?). And all the functionality is already there in the car you just paid for.

Reminds me of the old (1970's) days when a £1M upgrade to an IBM mainframe was done by an engineer who came out and snipped a wire on the backplane. In those days it was mainly businesses that got ripped of, now its all of us.

Possibly the original wall was built when the road surface sloped down like the top of the wall. If you could dig down below the pavement level, I suspect you would find the foundations of the wall sloped down below pavement level.

Subsequent road "improvements" have levelled the road surface.

I would imagine the issue is a basic problem with using a spring as the restoring force as the oscillator swings.

Gravity is pretty consistent (in the short term) as a restoring force acting on a pendulum, and the same in both directions of the swing.

A balance wheel obtains its restoring force from the balance spring and as a minimum - and probably inherently - the force in the two directions, one as the spring coils up from the mean position and one as the spring uncoils from the same position, will be different.

Gravity is a lot easier to get consistent.

Edited By Peter Cook 6 on 17/02/2023 12:09:02

My 1952 copy of "Motor Repair and Overhauling volume IV" says "Quite satisfactory performance may be obtained with condensers which vary in capacity between as much as 0.15 to 0.40 mfd". It goes on to say "...cars of high speed operation are usually fitted with condensers which have a capacity for lower limits ; for cars with normal slow speed performance , the condensers which give the best results are those with capacities near the higher loads"

Which seems to imply the capacity depended on the vehicle. It goes on to extensively describe the method for selecting the right size by running the vehicle for a few thousand miles, and then seeing where the pitting occurs. Pitting in the contact point of a negative earth vehicle shows the condenser is under capacity, whereas pitting on the arm suggests over capacity

I would assume they would be paper capacitors and rated for thousands of volts but the book doesn't say.

Just for closure and to thank Michael for the pointers.

I dredged up a 1925 patent on the spectroscope Espacenet – search results which shows the same compound prism in my unit when I stripped it down.

The patent says that the surface between the two sections of the prism should be half silvered, and the face of the prism should have a diffraction grating either applied or engraved on it.

Unfortunately the half silvering looks rather badly damaged, and is well beyond my abilities to repair, and I can't see the grating - although I have seen a spectrum through the device so I might one day persevere. But for now it goes on the bottom shelf. It came for free with a very useful travelling microscope to nothing is lost.

Thanks again Michael for the pointers.

Each time it does it, and you reset the pendulum length to get it back to time, do you return the pendulum bob to the same place - or is the bob getting progressively lower with each resetting?

I would mark (Sharpie or something similar) the pendulum rod just above the bob when the clock is correctly adjusted. When it starts galloping again, see where the bob is relative to the rod. If it hasn't moved, where does it go to when you get it back into regulation? Do you lower the bob down and then wind it back up to the same place?

It's possible that something is moving in the suspension. The suspension spring is cracked or the mounting point is loose. It moves somehow (agreed that would usually slow the clock, but you never know), and the action of winding the bob down a bit and then back up resets things.

Thank you Michael most interesting.- where do you find these things!! Now to work through the diagrams an d descriptions and try and figure out the similarities and differences.

Thanks again.

I acquired this thing, alongside a nice boxed travelling microscope, as part of an auction lot. The only connection I can see between the two is that the support pin for the microscope is the same diameter as the pin on this gadget.

Online research tells me that the bottom piece is a Beck prism spectroscope.

The other piece is clearly supposed to contain a light source and has a lens in the end to collimate the light. It does seem to work, as shining a bright light down the collimator tube and reflecting it through the slit makes a spectrum visible at the eye tube.

However the spectroscope is missing its eyepiece, and although the eye tube is 23.2mm in diameter, which seems fairly standard, there is a locating key on one side that will stop a circular eyepiece from entering.

Which raises a couple of queries which I am hoping the optics experts might be able to help with.

Does anyone know what focal length (or magnification) the eyepiece would have been - or have a method that would allow me to measure what it should be? I can't see any examples of eyepieces online with a flat on one side so I suspect I will have to get a lens and make a mount.

All the Beck spectrometers I can find online seem to be stand alone devices. Has anyone got any pointers to a picture that might show me the sort of specimen holding stage that this would have originally fitted?

Thanks in advance for any ideas.

I can't speak for ER25 - I only use the set I have in Stevenson blocks for work holding. However I have bought ER16 collets from both ARC and CTC tools. My ARC set are quoted as 0.008mm but I only got the standard (0.0015 ) tolerance set from CTC tools, but both sets work well and are more accurate than the specs.

I suspect both sets are Chinese (the CTC ones certainly are) , but I would have no quibble with either set. CTC quote their imperial ER25 set as 0.0006" Run-Out Tolerance, and do more precise ones in metric quoting 0.008mm (0.0003"  ).

One trick I have used is when trying to hold short lengths of material, is to put a same sized bar in the back of the collet. I often use a suitable drill shank.

Edited to remove random smiley!!

Edited By Peter Cook 6 on 12/02/2023 18:37:41

Knife edge suspensions are a bit more common on French clocks, not necessarily precision ones. And they do seem to last fairly well.

This is a French clock dated to about 1790 which is suspended from a knife edge suspension at the top. The whole clock acts as the pendulum. The suspension is ( I think) steel on steel.

Something like

With an M4 (0.7) thread at the top and an M5 (0.8) thread at the bottom, each full turn of the thumbwheel would lift or lower the top bar 0.1mm 0.004". So one quarter turn would give you the 0.001" adjustment

Edited By Peter Cook 6 on 01/02/2023 22:23:51

I was not worried about hand turning with an ER collet chuck. It was doing so with a standard 3 or 4 jaw!

I recently bought some fairly cheap Chinese made 6ft 60W LED battens to replace the fluorescents in the workshop.

Two failed (one DOA - transit damage - and one shortly after installing). Both were replaced without quibble under warranty.

I decided to open the failed units (they did not want them back) and see if there was anything useful inside (as you do!). One had failed due to a badly soldered wire - very quick fix. The other had a blown chip - magic smoke had come out. They are interesting in design. They have two 3ft strips each with two rows of 75 LED's end to end. Driver electronics for each strip are in the ends, and mains voltage is carried from end to end down tracks on the strips.

The strips looked useful if I could obtain replacement drivers. So I measured the DC voltage used by the strips in one of the working units. 420V+ !!!

Presumably the 150 LED's in each strip are in series and the drive electronics supplies 70ma from full wave rectified mains voltage.

Anyone seen a source of (cheap) LED drivers that push out 400+volts?

Edited By Peter Cook 6 on 31/01/2023 15:10:35