Roughness Comparison Specimens

[TeeJay]

In one of the current topics "engine failure update" I made a small contribution about Surface Finish of the Cylinder Head.

That evening I had a flash back to my 5 years as a Student Apprentice of which 3 years was in a Machine Shop. Hope there's no shrinks reading this.

At that moment of time I had "hands on" with Drilling, Milling and Turning machines.
Surface measurement was done by Roughness Comparison Specimens and instead of going to the tool stores to withdraw the gauge I purchased my own and I still have it today as shown in the photo.

Although it states "Turning" it could also be used for certain types of Milling e.g. Fly cutting and slab milling. i.e. the milling technique as applied to machining the Twink cylinder head.

You used your finger nail to run across the machined surface and then the Comparison Specimens to compare and it worked very well.

How very different to today's Inspection / surface measurement equipment.

Any others remember the Roughness Comparison Specimens, were really not that old, are we.

OK OK I have now woken up and returned to the day job of being retired.

PS. Is anyone else having problems with the Smilies and putting photos in line?

[Chancer]

Still got mine, kept with my zeus book, slip guages, thread guages, sine bar (one of my first year apprentice projects) file card (havn't seen one of those for years) etc etc etc.

I now have a small lathe and mill so the stuff eventually got re-used as did my late fathers engineering tools which he handed down to me.

It makes you sit up and think when you pick up an electronic vernier caliper for ?8 whilst shopping at Aldi saying at that price I'll keep it as a spare only to find that its far better then the manual one that cost me a months wages!

[Galwaylotus]

PS. Is anyone else having problems with the Smilies and putting photos in line?

They haven't been working for me today.

[GrUmPyBoDgEr]

Oh yes I remember them well but only as a comparison & basically a training aid for machinists etc.
How true about digital calipers; they can be so cheap & now the batteries can be bought in ?1 shops!
A few years ago it was a toss up; buy a battery or a new caliper!

How times change------------------Visualise a rolling eyes smiley here please!

Cheers
John

[69S4]

Can't make any helpful comment on surface finishes but can't put the confused smilie in either to explain why - to this post or any other recently. As for trying to post pictures - where's the mad smilie when I need it ! I spent nearly two hours yesterday trying to include one.

[el-saturn]

.................and here's the swiss version for all of you ROUGH fellas! cheers sandy

[TeeJay]

Ahhh, the Swiss version, a Swiss wallet always was filled with many goodies. In this particular wallet, many items representing several surface specimens, Hoeing, Grinding etc.
Although probably not worth as much as the twink oil cap.

A Sine Bar and File card, had to think a little about the file card, but then:- A card with steel bristles.

The Training Manager always insisted that the files were cleaned with the file card before being put away.

I never made a sine bar, but V blocks & clamps, table screw jacks, scribing block etc.
But the "pi?ce de r?sistance" was a T and a U test piece made from steel plate. We had to mark it off, saw and file it.
The idea being that the T had to perfectly fit into the U and was held up to the light to see any gaps. Gaps as small as 0.001" could be seen.
The real reason behind the test piece was to highlight that if you removed to much metal the component was scrap.

Happy Days.

[el-saturn]

.............sure rings a bell: we had to file a male and female square profile at H7 / h7 accuracy
at this workshop training - i did pretty well! i never actually needed this so called rugo-test BUT
i had to show it to you - i would sell it if its worth enough - i?d also would trade it. sandy
...............just remembered that we used chalk to get the nice surface!

[Chancer]

Sounds like the notched square we had to make.

I had to nip mine up a little in the flypress!!!