Member postings for Speedy Builder5

Today, the washing M/c engineer arrived (Wash M/c under guarantee). It had jetted about 30 litres of water over the kitchen floor before anyone realised it had gone wrong. On inspection, he found an old 'RAC' yale key had been 'shot' through the plastic casing after being picked up by the spinning drum. Unfortunately not covered by the guarantee or his time for the callout. Estimated repair cost in excess of 440 euros plus 65 for the callout.

Now, which grandson of mine lost an RAC key, and who didn't check his pockets before washing??? Cos its strange that a key like that should turn up in SW France - It certainly wasn't me !!

Anyway, check out E-bay if you want secondhand components as we had to buy a new machine - no more new tools for me before Christmas I suppose.

BobH

It may be easier to make some little clamps and clamp it to the machine ?

BobH

Thanks for the site ref, but it doesn't go near to 48mm dia threads 1.5mm pitch (or thereabouts) Would it be reasonable to think that with thread rounding, the thread OD would change from 48.786 to 48mm But is this just wishful thinking.

Problem is that the car is not next to the lathe, but some distance away and I would like to be able to produce a test piece somewhere near correct at the first bash.

BobH

I have been asked to make some (Male) screwed hub dust plugs for a vintage Bugatti.

These screw into a female thread which is 47mm inside diameter and 1.5mm pitch. When I look at various charts, the inside diameter of a 1.5mm pitch screwed nut is D - 1.786mm . This would make the nominal diameter 48.786. This seems a weird size. I had a go with 'Thread Pal' as posted last week, but that didn't help as it would not 'fit' on my notebook screen

Any ideas folks ?

BobH

I am a right pain in the buttocks, but on my mike, the spindle is 1.7" long before the start of the thread, so assuming the Mike is opened up to 1", there will still be 1.7" of spindle that will expand in the opposite direction, however the screwed section of the frame will counteract this expansion, so once again things are in equilibrium. All in all, a micrometer is a very clever design compared to a vernier calliper. Do digital callipers have a thermal compensation device in them ?

BobH

I am not going into the mathematics, but as heat increases, the frame expands in a positive direction, the spindle (allbeit a shorter length than the frame) expands in the opposite direction. So, the frame counteracts the test block expansion, but the spindle reduces the measured standard. Hence 'Standard rooms' were kept at a constant known temperature. ???

BobH

We think the clue was "Found in South West France". looking on the web **LINK**

It talks about the 'Toise' and then the Pied de Rois (or foot of the King). This being 32.66 Cm which divided by 12 becomes 2.7216 recurring. Not quite 27.38 mm, however there were regional difference and as SW France is some way from Paris, we think this may be the explanation. But always open to opinion.

BobH

Ah well, 1 Cm on the calliper = 1Cm on my modern rule. Over the 10 Cm of the Calliper it measures 99.8 Mm, but I think this may be wear and tear and general abuse of the instrument.

I think that this still leaves us somewhere near Neil's first post, but not quite ! However I do like the patternmakers idea. But why would an 'inch' be divided into twelfths ?

Bob H

My sources say that Neil is not quite there as 1 = 27.38 mm. Keep it going.

And another mystery object:-

Obviously a calliper, but one side is engraved in Millimeters/Centimeters the other in "inches", but not quite as each "inch" is 27.38 mm (1.078" ) and each "inch" is subdivided into twelfths. The overall measuring length is 13 Cm. Its rustic and has a lot of age to it (hardly precision). My other clue is that it was found in SW France. No prizes, but I will be interested in your thoughts.

Bob H

Edited By Speedy Builder5 on 05/09/2014 19:00:33

I guess it all depends upon what you are going to use them for. If you have a lathe and milling machine, then I doubt you will be more accurate than 0.0005", so having blocks that are certified to a precision greater than this is a bit OTT. As you say, you got them for a song so what the hec. Honestly, dip them in white spirit for a while and then just wipe them clean. If they are real carbide, then you will need diamond paper to do any real damage to them. Dropping them on the floor will do the most damage.

My advice, get on and use them before they accumulate another layer of dust.

Bob H

At our first house - space was limited, so I cantilevered the lathe out from the wall so the bonnet of the car could pass underneath the bed of the lathe (no cabinet). Not ideal, but it worked.

BobH

BW Electronics www.http://bwelectronics.co.uk/

Smashing bit of kit - later models had all sorts of enhancements.

BobH

My coolant pump which is labelled 240/440 volts runs fine on single phase 240v with a 12Uf capacitor in circuit all the time.

Well, it does say on the mike - 0.0005" so I guess that means to the nearest 0.0005". So, when it reads 0.0005 it IS zero ?? - Just being pendantic - sorry.

BobH

It sounds a bit too late now, but perhaps you should have used a thread insert which would have brought the tapped hole back to its original size. I think that what you are in fact making is a stepped stud which is 10mm on one end and 6mm on the other. May be a lot easier to get a 10mm bolt, turn one end down to 6mm, then run a die down the 6mm bit.

Kevin, what sort of knurling tool makes those nice swirls ?

BobH

Had a friend who called round with an electric single phase pool pump.Sometimes it ran, sometimes backwards (he said) and some times just sat there and hummed.

There isn't any switchgear inside, so I guessed it was a capacitor run motor. Dug around in the come in handy box and found an identical 16 Uf capacitor. Fitted it and now he is a happy bunny again. So am I as I fancy a swim tomorrow.

who said "marriage is not a word - just a sentence"!!

Just watch out, as your 5/16 x 20tpi may be 55degree thread angle and the 8mm will be 60degree.