By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Oct 22nd

What Did You Do Today 2019

All Topics | Latest Posts

Search for:  in Thread Title in  
Ian Johnson 123/10/2019 22:55:06
170 forum posts
50 photos

Today I've mostly been repairing a box, because I finally treated myself to a gauge block set last Friday at the Model Engineering Show, it's a Coventry Matrix good quality 50 piece set but the bakelite box was broken at the hinge side, so it needed repairing!

20191018_204540.jpg

The set has a RR sticker on it so it must be good! Calibration valid until 1996 so it's just out of date! Weirdly the top of the box is made of wood so it must have been repaired before.

20191021_195826.jpg

Clamped in the vice showing the damage to hinge side. Contemplating hack-sawing the damaged bit off.

20191022_164313.jpg

Decided to mill the damaged bit off. Impressive bit of clamping don't you think?

20191022_184802.jpg

New piece of hard wood inserted and glued into place, then milled down to size, and hinge pockets were also milled in.

20191023_200144.jpg

Lid fitted and lettering re-whitened, bit of polish and the jobs a good 'un!

Very pleased with the gauge block set, most pieces will wring together apart from the larger sizes, so it has seen a lot of use, but checking the pieces with my digital micrometer down to five decimal places, it is still extremely accurate, certainly good enough for my use.

Ian

geoff walker 124/10/2019 09:14:49
332 forum posts
144 photos

Job is a very good 'un Ian. Well done. There something very satisfying about a sensitive refurbishment like that.

I remember my dad had a set, for some reason he called them "joe" blocks. No idea why?

Geoff

Baz24/10/2019 09:19:08
267 forum posts

They were called joe blocks because some sets were made by a company called joehannsen, not sure if I have spelt that correctly though.

Swarf, Mostly!24/10/2019 10:27:22
498 forum posts
41 photos

That looks like a good repair.

However, I hope that piece of hard wood isn't oak. If it is, I'd advise a coat of varnish, pdq!

Best regards,

Swarf, Mostly!

Nicholas Farr24/10/2019 10:46:57
avatar
1992 forum posts
950 photos

Hi, if it is Oak, don't use steel screws in it, as they will rust. Brass is the ideal screw for Oak.

Regards Nick.

SillyOldDuffer24/10/2019 12:16:29
4785 forum posts
1011 photos
Posted by Baz on 24/10/2019 09:19:08:

They were called joe blocks because some sets were made by a company called joehannsen, not sure if I have spelt that correctly though.

More than 'some sets were made by', Gauge Blocks and the first effective process for making them were both invented by Carl Edvard Johansson. As Johansson was the only source for many years (later in association with Ford and Brown & Sharpe), Jo Block came to mean any Gauge Block, much like Hoover means any Vacuum Cleaner. But since other people found ways of making gauge blocks in the 1930s, 'Jo Blocks' have slowly faded from memory. Johansson should be celebrated as a major force behind the introduction of modern precision engineering.

Dave

JasonB24/10/2019 12:27:58
avatar
Moderator
16446 forum posts
1739 photos
1 articles

Not sure why they get called Joe blocks if named after Johansson surely they should be Jo blocks pronounced YO as in Yo ho ho

Ian Johnson 124/10/2019 13:26:08
170 forum posts
50 photos

Yes it was a satisfying quick repair to a set which will out live me, hopefully to be passed on to someone else in the future. I'll leave the bare wood as it is, as a proud in your face repair! It's 'Heveawood' or Banana wood (from a chopping board) the same stuff as I made my base for my ongoing Stothert & Pitt Beam engine project.

I've mostly called them slip gauges when I was on the tools, but Jo blocks are a common name too especially in America where I think Ford bought the company. And for thirty quid I thought it was a reasonable price for a quality piece of kit.

Ian

Michael Gilligan24/10/2019 14:23:38
avatar
14134 forum posts
615 photos
Posted by JasonB on 24/10/2019 12:27:58:

Not sure why they get called Joe blocks if named after Johansson surely they should be Jo blocks pronounced YO as in Yo ho ho

.

A hearty welcome to pedants' corner, Jason angel

MichaelG.

Robert B24/10/2019 16:22:21
8 forum posts

"I'll leave the bare wood as it is"

Knowing the black marks on our kitchen wooden work top, not oak, and experience with acidic wood I would seal it ASP. Those small bits of precise steel need looking after.

Rob

Ian Johnson 124/10/2019 21:57:44
170 forum posts
50 photos

Thanks guys I didn't realise that a piece of wood could be so dangerous! So I dyed it with a brown stain and black ink jet ink on top, invisible (ish) mending at its best!

20191024_195224.jpg

Just got to get rid of the black ink of my fingers now! Tried everything, meths, acetone, cellulose, WD40 even tried Trichloroethane 111, there is no quick way of getting rid of ink jet ink off skin! I'll just have to wait until my skin cells regenerate!

Ian

Mick B124/10/2019 22:13:33
1214 forum posts
70 photos
Posted by Ian Johnson 1 on 24/10/2019 21:57:44:

Thanks guys I didn't realise that a piece of wood could be so dangerous!

....

Ian

Hmmm... maybe no need for too much hurry - here's an oak model gun carriage and a silver steel trunnion it's been in close contact with for 16+ years.

24prTrunnion.jpg

I don't think the bluing was immaculate from the start.

Mark Rand24/10/2019 22:32:46
785 forum posts

There was a touch of varnish the wood though!

Bazyle25/10/2019 00:05:57
avatar
4761 forum posts
187 photos

It's not much of a problem if it is dry - I assume MG keeps his models inside.

Ian Johnson 125/10/2019 01:40:31
170 forum posts
50 photos
Posted by Mick B1 on 24/10/2019 22:13:33:
Posted by Ian Johnson 1 on 24/10/2019 21:57:44:

Thanks guys I didn't realise that a piece of wood could be so dangerous!

....

Ian

Hmmm... maybe no need for too much hurry - here's an oak model gun carriage and a silver steel trunnion it's been in close contact with for 16+ years.

I was going to stain and protect the wood sooner or later, but the replies gave me the urge to do it sooner!

Ian

Michael Gilligan25/10/2019 05:40:38
avatar
14134 forum posts
615 photos

sorry to divert from Ian’s discussion, but iOS users should probably read this: **LINK**

https://www.popularmechanics.com/technology/apps/a29575329/iphone-apps-malware/

MichaelG.

Nigel Graham 225/10/2019 13:41:39
427 forum posts

Ian Johnson-

Printer ink stains.

This seems a daft question, but did you try just water (and soap) to remove the ink from your hands?

Some ink-jet inks are soluble in water rather than mineral-oils - I have used this to destroy sensitive documents before I bought a shredder!

SillyOldDuffer25/10/2019 14:19:11
4785 forum posts
1011 photos
Posted by Ian Johnson 1 on 23/10/2019 22:55:06:

... it's a Coventry Matrix good quality 50 piece set ...

The set has a RR sticker on it so it must be good! Calibration valid until 1996 so it's just out of date! ...

...most pieces will wring together apart from the larger sizes, so it has seen a lot of use, but checking the pieces with my digital micrometer down to five decimal places, it is still extremely accurate, certainly good enough for my use.

Ian

I guess Ian wants a set of gauge blocks for the same reason as me - a way of checking my distinctly ordinary digital calipers and micrometer. As my calipers are ±0.02mm at best, it's occasionally useful to pin them down more tightly. At ±0.01mm my micrometer is usually good enough for my purposes but it would be useful to confirm accuracy is really achieved across the full 0 to 25mm range. A set of second-hand gauge blocks would suit me fine.

But be warned - maintaining accuracy when it truly matters is a tricky business. Perhaps the main reason for needing to frequently recalibrate measuring instruments is wear and tear. For ordinary purposes, it's sensible to check workshop tools against Gauge Blocks because even a cheap set outperforms most measuring tools. It doesn't matter who made a favourite micrometer, what matters is cold test results, which gauge blocks will deliver.

Unfortunately, being high-precision means Gauge blocks are themselves particularly prone to damage and they need much TLC. This includes the need to be regularly recalibrated against a higher standard set, at least once every 5 years on a light use set, maybe 2 or 3 times or more a year for anything busy. Recalibration is serious business: it's meant to be regular, traceable and certificated. A set of Gauge blocks can't meaningfully be measured with a good micrometer because a good condition block should be at least 4 to 10 times more accurate than the micrometer. (British Standard Workshop Grade 'B' Gauge Blocks are +0.25μm to -0.15μm. The AAA blocks made for Laboratories and Standard checking are ±0.05μm, well into calibration by interferometric methods.)

That a set of gauges was carefully made from the best materials by Coventry Matrix and bought by Rolls Royce matters not one jot compared with their current condition. Last calibration being in 1996 probably means it failed the next test. At that point RR would retire it from precision work, but it would still be an asset in a home workshop. Just don't imagine it's still a quality set! Like me, it's seen better days...

Dave

Edited By SillyOldDuffer on 25/10/2019 14:22:01

Mick B125/10/2019 14:37:55
1214 forum posts
70 photos

Unless it's being used for some extremely exotic work where way sub-micron tolerances are critically necessary, I'd think this set's accuracy will be very comfortably more than adequate.

Baz25/10/2019 15:04:39
267 forum posts

All our sets of slips that failed calibration were given to the machine shop where they were mostly used on the lathes as length stops.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Support Our Partners
TRANSWAVE Converters
Warco
cowbells
Meridienne; London MES
Eccentric July 5 2018
Eccentric Engineering
Ausee.com.au
ChesterUK
emcomachinetools
Allendale Electronics
Subscription Offer

Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

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.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest