By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Rulers - my pet peeve

All Topics | Latest Posts

Search for:  in Thread Title in  
<< First < Prev 1 2 3 4 5 6 Next > Last >>
magpie29/12/2010 14:28:30
avatar
508 forum posts
98 photos
Hi Spurry.
                   I would be carefull with that M&W one in the photo, It looks like you have worn about   0.2mm off the end !!!!!!
 
                                                        Cheers  Derek
chris stephens30/12/2010 13:36:04
1049 forum posts
1 photos
Hi Terry,
There is an operation that can be performed to cure your little problem, or you could try rigging up a vacuum pump.

chriStephens 
chris stephens30/12/2010 13:37:00
1049 forum posts
1 photos
Hi Terry,
There is an operation that can be performed to cure your little problem, or you could try rigging up a vacuum pump.

chriStephens 
Stub Mandrel30/12/2010 19:01:25
avatar
4318 forum posts
291 photos
1 articles
Out of interest, how competently do folk think they can estimate subdivisions?
 
In chemistry at school and map-reading in the scouts I was expected to estimate tenths to within a tenth either way. I find this handy on my hom,e-made rotary table as the handwheel is graduated to a tenth of a degree and accuracy to about 1 minute of arc seems plenty for my humble needs, such as gear cutting.
 
Neil
 
 
Peter G. Shaw30/12/2010 19:52:22
avatar
1531 forum posts
44 photos
Neil,
 
A long time ago I discovered that some of the rule(r)s I own did not agree. Furthermore, I also discovered discrepancies between the various micrometers, manual verniers and electronic verniers. Eventually I bought the three smallest metric Mitutoyo micrometer standards and started comparing both for identical readings and for tolerances. Generally, where possible I estimated to tenths - not possible on digital stuff, but can be done on the manual micrometers, both metric and imperial.
 
I then borrowed an imperial micrometer from an ex-toolroom toolmaker friend as it had the tenths vernier scale. Much to my surprise, I found that my estimated readings compared very favourably with the actual tenths micrometer and on mentioning this to my friend found that he was not at all surprised. He said that the human brain and eye was very capable of doing this.
 
For myself, I would have expected 1/4, 1/2 & 3/4 of a division to be reasonably easy to do, and somewhere I picked up the idea that the graduations are usually approximately equal to 1/10, so probably 1/10 and 9/10 should be ok, but this then leaves 2, 3, 4, 6, 7 & 8 tenths as probably being the most error prone.
 
Regards,
 
Peter G. Shaw
 
PS For what it's worth, I ended up with a metric micrometer reading 0.005mm high at 25mm, a slide vernier caliper with a resolution of 0.05mm appearing to be exact,  a Draper dial caliper with a resolution of 0.02mm reading consistently high (and since given to my grandson), a Rolson digital caliper which appears to be reading up to 0.02-0.03mm low (within spec), and a Workzone digital caliper from Aldi which reads anything up to 0.11mm high and isn't even consistant.
 
Since then I have bought a Starrett 25-50mm micrometer and a Starrett 150mm dial caliper with a resolution of 0.01mm. Both of these seem to be accurate. Hence I now use the 0.05mm slide vernier as first choice with the micrometers and the Starrett dial caliper second choice and the Rolson digital third choice.
 
Anybody want a Workzone digital caliper? Going cheap for postage!
Speedy Builder502/01/2011 20:37:20
2878 forum posts
248 photos
Hi John,  I have a Rabone Chesterman  300mm rule CF 49  to Bs 4372 square ended satin finished stainless steel.  -easy read for pensioners.
 
One face is in mm,  the other in 1/2 mm graduations.  The top reads right to left (albeit upside down) ,  the bottom left to right.  It has square ends -and its all mine !
Speedy Builder502/01/2011 20:54:46
2878 forum posts
248 photos
John,  quick,  check out E-bay  Item number: 350414102041
 
Rabone CF 49 is up for sale - its the satin one with a hole in it.
 
Good luck
John Stevenson02/01/2011 21:36:45
avatar
5068 forum posts
3 photos
Robert,
Sorry not following you?
That one is marked in 1/2mm which is what I want to get away from.
What I want and have now found and ordered from Germany are rules with full mm divisions on all sides.
 
I'll post some pics when they arrive in the new years, nobody will be shipping until Tuesday anyway
 
John S.
Gordon W03/01/2011 09:57:08
2011 forum posts
When I was an apprentice (what dread words) we were given 6" rules. Then taken to the holy place (tool room). Rules set in a square on surface table ,and with a tool room height gauge set to standard increments ,ie. 1", 1 1/2" etc. the rules were scribed. This showed the true division mark, after that we were expected to measure to 15 thou. with them.
Stub Mandrel07/01/2011 19:57:55
avatar
4318 forum posts
291 photos
1 articles
I'm going to do an experiment - I have a 1" standard and I'll take photos of each of my calipers and micrometers on it. You'll have to trust me to zero them properly!
 
Neil
 
P.S. My workzone caliper is the one I use most as the chunky body fits the hand and it seems at least as relaible as the others!
 
P.P.S. Any dirt at all on the 'scale' is the enemy of accuracy and consistency with digital calipers.
Nicholas Farr07/01/2011 20:06:52
avatar
3988 forum posts
1799 photos
Hi Neil, I hope you are going to maintain them all at their specified accuracy temperatures during your experiment..
 
I was checking a couple of 2"-3" mics last night and just handling the 2" and 3" standards made a difference of 0.0005". I had to get them all up to my handling temp before I got consistant readings.
 
Regards Nick.

Edited By Nicholas Farr on 07/01/2011 20:08:22

Peter G. Shaw07/01/2011 21:04:19
avatar
1531 forum posts
44 photos
When I was checking my devices, I brought them into the house overnight before checking, thus ensuring that they were all at the same temperature, 20°C or as near as the storage heaters could get it.
 
In respect of the micrometers and the standards, they were all held by the plastic insulating pads: my understanding is that these, especially on the standards, are designed to minimize heat transmission from the hands. The calipers are rather more awkward since they are mainly all metal. One way is to hold them as much as possible in say a portable vice fitted with plastic jaws. Provided the vice has also been left overnight in the same room, it should then be at the same temperature as the caliper under test and the standards.
 
Regards,
 
Peter G. Shaw
Nicholas Farr07/01/2011 21:27:02
avatar
3988 forum posts
1799 photos
Hi Peter, I think your ideas are very valid. My standards don't have any plastic insulating pads. I was also thinking that it would be easyer if they were gentle nipped in a vice, as trying to hold the mic and the standard and working the mic's barrel all at the same time was rather akward to say the least. I've got an ali vice which will clamp onto a table top, somwhere which was a freebie with a cheapo workmate type thingy, I'll have to see if I can find it.
 
Regards Nick.

Edited By Nicholas Farr on 07/01/2011 21:27:48

Dave Jones 108/01/2011 11:36:49
85 forum posts
5 photos
Being from a slightly younger generation, I had the luxury of missing out of capital punishment in school! on the downside this means it was not explained to me why you cant call it a ruler.  So why is this?
 
This also means I have had to teach myself how to work in imperial instead of metric, but that is a whole other can of worms!
 
Dave
Terryd08/01/2011 11:51:03
avatar
1946 forum posts
179 photos
Hi Dave,
 
I am from an older generation but I don't know of any reason why you can't call it a ruler, but there are reasons why you can
 
Quote:
 
"ruler [ˈruːlə]
n
1. (Government, Politics & Diplomacy) a person who rules or commands
2. (Engineering / Tools) Also called rule a strip of wood, metal, or other material, having straight edges graduated usually in millimetres or inches, used for measuring and drawing straight lines
 
Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003"
 
end quote.
 

 
That's good enough for me,
 
Regards
 
Terry.
 

John Stevenson08/01/2011 11:53:29
avatar
5068 forum posts
3 photos
Well they arrived from Germany via DHL on Thursday,
Just as it says on the box, 13mm wide, very flexible and just right for the top pocket.
 
Bought two 100mm long ones, two 150mm long, two 200mm long and one 150mm one that reads right to left so should be set now for a while, one set into the shop and one set as spare in the office.
 

[Edit] one 150mm and one 200mm has already gone into the shop.
 
John S.

Edited By John Stevenson on 08/01/2011 12:00:45

blowlamp08/01/2011 11:58:56
avatar
1885 forum posts
111 photos
Posted by Dave Jones 1 on 08/01/2011 11:36:49:
...I had the luxury of missing out of capital punishment in school! ...
 
Dave
 
 
 
 
Good job you did, or we wouldn't have the pleasure of your company
 
 
Martin.
Dusty08/01/2011 12:34:27
498 forum posts
9 photos
Hi guys
     Remember that when using standards to set measuring equipment that whatever you are setting is only accurate at the size of your standard, you are relying on the inherent accuracy of the tool thereafter. If you have the use of a set of slip gauges then you can check across the range of the tool you are trying to set. If you then find you have an error then I would suggest that you balance the error over the range of the tool.
i.e. set it so that it is accurate at the midway point.
NJH08/01/2011 13:10:45
avatar
2314 forum posts
139 photos
Hey John
Like the look of those - maybe I will order a couple.
 
As far as the top pocket goes though take care that you don't stick the 200mm version up your nose!! (Insert smiley here - but of course I don't do those)
 
Regards
 
Norman
Terryd08/01/2011 15:14:12
avatar
1946 forum posts
179 photos
Hi Chris Stevens,
 
I also have a metre stick!
 
Best regards,
 
Terry
<< First < Prev 1 2 3 4 5 6 Next > Last >>

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

Sign up to our Newsletter

Sign up to our newsletter and get a free digital issue.

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts
Support Our Partners
cowells
Sarik
MERIDIENNE EXHIBITIONS LTD
Shopping Partners
Subscription Offer

Latest "For Sale" Ads
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

 

Donate

donate