Here is a list of all the postings ANDY CAWLEY has made in our forums. Click on a thread name to jump to the thread.
|Thread: Coventry Gauge Micro Maag|
Still cant get text below photo!
I was at this point that I discovered that the black sleeve will not slide when the measuring prongs are tight home on the bore.
It seems that the method is:-
Now that is really clever because it diminishes the need for "feel".
Edited By ANDY CAWLEY on 01/05/2015 18:35:58
I don't seem to be able to type any text in below the photo nor add a second photo, what am I doing wrong.
To continue:- Knowing the diameter of the setting gauge I thought that I would adjust the thimble until it registered the diameter of 0.75003 and then lock the thimble.
Right then! I've been in the shed and learned a bit more- I think I've cracked it.
The setting gauge was 0.75003 and thimble also needed adjusting. The fiducial line has three marks on it, one just on the thimble end, a short one and a long one. The short one represents mid point on the tapered peg and the two others represent + & - 3 thou for that particular peg.
I discovered that when the thimble is screwed right in when there is no measuring head in place the black slider will not slide. Wind it back a little bit and it slides back with a click.
Edited By ANDY CAWLEY on 01/05/2015 18:24:05
Chortle, chortle ! , no you're far from being rude, it's me that's being gormless!
I must get my grand children to post for me.
Thanks, that's just the kind of advice I was looking for.
I realised that "feel" was very important, that's why I came here looking for guidance before I damaged anything.
I'll have another go and report back.
KWIL, That's what I thought too.
I tried setting it below .750 (or so I thought) and it was still tight.
Maybe I'm being fooled by the 20 divisions to the thou and I'm being too clumsy. I'd better go back and have another go.
A bit of discussion and guidance always seems to help.
It's too good a bit of kit to give up on or wreck!
Thank you very much
It would be even nicer if somebody could tell me how to use it
The setting gauge is 0.75003 dia.
When I attach the appropriate taper pin and set the thimble to =0.000 and insert it in the setting gauge by retracting the black sleeve and then releasing the sleeve the measuring head (that's what I call the bit with the three probes) is well and truly held tight in the setting ring.
I don't know what to do next. Because it is such a precision piece of kit Im scared of damaging it through ignorance.
I was rather hoping that some one on this forum might have experience in using one of these things and would be able to tell me what to do or point me to an instruction manual. I have Googled with out success.
Edited By ANDY CAWLEY on 01/05/2015 09:31:59
ihave a Coventry Gauge Micro Maag which I acquired some time ago.
It is a three point bore measuring device. There are several heads and the three points are forced outwards by a taper pin which is moved by a thimble . There are ten of these tapered pins each with a range of +/- 3 thou.
The black bit is a spring loaded plunger which moves the tapered pin however
i can't figure out exactly how to use it properly.
Can anybody hel?
Edits he black ed By ANDY CAWLEY on 01/05/2015 01:
Edited By ANDY CAWLEY on 01/05/2015 02:03:50
Edited By ANDY CAWLEY on 01/05/2015 02:05:26
|Thread: What did you do today (2015)|
My first attempt at using a boring head to turn an outside diameter. The spigot on the timing case cover acts as a front engine mount and after 90 years showed 40mm of eccentric wear which, on installation in the chassis, was by observation evidently too much😒!
After a visit to our local welding genius the weld build up had to be machined. The obvious method of sticking it on the face plate of the lathe was thwarted by not having enough swing so on to the mill it went. Not having the requisite left hand boring bar I had to run the mill in reverse taking the precaution of winding the boring head onto the stub arbour with a big adjustable spanner. I got away with it unscrewing by taking light cuts.
Funnily enough austenitic (non magnetic type) stainless can become magnetic due to cold working so the magnet test is not infallible.
Ian, the 3 cylinder W is on my project list meanwhile all my machining time is devoted to getting my full sized job going properly.
Tidying my bench revealed the spring that I intended to use in the first place. Today's efforts were therefor doing the job properly. The spring came off a modern tensioner that I hah hoped to use but it wouldn't fit into the space available. This is what the sensible spring looks like rather than the previous Mickey Mouse effort.
Hey Ian, mine's the real thing as well😉!! Just happens to be a 4 cylinder water cold car engine.
You are right about the spring angle but I ran out of time and patience.
Edited By ANDY CAWLEY on 06/04/2015 06:49:02
Finished the magneto timing chain tensioner for the Anzani. Got there in the end after several "measure once cut twice moments" when wil I ever learn?😁 still not really happy about the spring angle of attack but I think it will work.
Edited By ANDY CAWLEY on 05/04/2015 10:19:18
Dialled in the camshaft on the Anzani after four year rebuild! This included making replacement mag drive bearing from cast Babett,making replacement rollers for the tappets and making vernier ( well adjustable) cam drive sprocket.
The crank case in the back ground is mis leading, it is a replica of the Bleriot engine that crossed the channel.
Edited to add , yesterday actually.
Edited By ANDY CAWLEY on 10/03/2015 08:56:05
Edited By ANDY CAWLEY on 10/03/2015 08:57:58
Edited By ANDY CAWLEY on 10/03/2015 08:59:29
What's it like for wheeling tool boxes on castors?
|Thread: Good Quality Small Lathe|
You can buy, via Abebooks, the paper back version for £2.95, from India plus £4.00 postage.
Not bad eh?
I've just ordered one😀
|Thread: Drawn pinion rod?|
I too worked in the steel wire and wire rope industry for all my working life. As a management trainee, in 1961 I was sent to a wire mill in Warrington one of whose products, believe it or not, was pinion wire.
This particular mill was antiquated even in 1962. Whilst in our main mills in Doncaster an Cleckheaton we were drawing wire at high speeds through tungsten carbide dies on multi hole machines at Warring ton they were still using old fashioned draw plates or if I recall correctly they were known locally as whortle plates.
Wire drawing was in those days clearly divided into mild steel (below 0.40% carbon content) and high carbon, high tensile steel wire used for rope makinf and spring making principally. To produce high carbon steel wire in those days you needed the "patenting" furnaces referred to in Mark C's post. The mill at Warrington did not possess the patenting furnace and was due for closure. Not before I learned something of the old fashioned way of wire drawing.
Wire drawing consists of pulling the wire through a hole smaller than itself, if you see what I mean.
The hole is trumpet shaped and the trumpet is there to draw in the lubricant which was soap. The whortle plate was, from memory, a couple of inches thick and about 18" x 6" and had a series of holes in rows along its length. The entry holes were quite large compared to the size of the wire that was to be drawn.. The bottom of the lagge hole started off blind and the appropriate hole was made in it using punches and files. The wire drawer, a very highly skilled man, made all his own tools. The trade was so respected in Warrington, a wire town, that some pubs had bars that were only accessible to fully skilled men.
This method of plate drawing was used in the early days for drawing round wire until the tungsten carbide die came along however it remained for mild steel shaped wire because of its versatility.
Shaped wire started off round and the shape of the hole through which it was pulled was progressively pulled were gradually altered until the final shape was arrived at.
I surmise, as I never consciously looked at pinion wire production, that the round gradually became a polygon of the same number of sides as the number of leaves of the pinion. The sides of the polygon would then begin to take the shape of the pinion. The progression would be down to the skill and experience of the wire drawer. Sizes and shapes would have been determined by drawing soft annealed copper wire through the did.
One of the the thing that sticks in my mind was that the whortle plate was made of a very high manganese content steel. When the die was not drawing to size the steel was anneale and then "banged up", that is the back side of the die was whacked with a ball pein hammer to close up the hole, the high manganese content ensured rapid work hardening to give longevity to the reformed die hole.
Which reminds me the shaped wire was given several annealings during the course of its transformation from round to pinion shaped.
It was all 50 odd years ago and I don't think I knew then the full implications of "pinion" wire. We also made "pippin" wire which apparently was used as the knife edge for weighing scales or should I say balance.
|Thread: Help on key for 4-jaw chuck needed|
When making your key make sure it is long enough for the Tommy bar to clear the dial gauge used in setting the work in the chuck. I made mine too short and it is a constant source of irritation, I must make a longer one!😢
|Thread: Cast white metal bearing advice needed.|
The original item is cast white metal and has lasted very well for 89 years. It's just me who is a clumsy b*st*rd that broke it.
As I said in my OP, of course, it would make sense to machine from solid but that is not what I want to do, I want to stick to original specification.
On the moulding rubber question I had a long conversation with some one who uses the very hard grade professionally and he told me that because of the very high viscosity of the un cured resin a very high vacuum is need to properly degass the mix. He also said it is impossible to avoid air entrapment and get a good mix.
So casting white metal it is then!!!!
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.