Conversion Chart

For info:

It turns out that the "Monument" version of the Shetack DTC is the real thing ...

See here

MichaelG.

Hi Bazyle,

Here are pictures of both sides of my, rather old, Shetack. It's not identical to Bob's, but it does have Metric data as well as Imperial.

Gary, check your PMs, or look at my album postings. The last 3 photos are from my SHETACK calculator.

Hi David,
Still think that this a great idea ignore the ChEEP CHEEP's as I call them more noise than anything elso. The new people and even me who still has to go to old charts for example what drill do I use on a 5/16"ME hole to tap!! I am quite sure that many of us would not know that of the top of there heads, But I am sure some smartarse will tell me once he has looked it up.

Have you got an old Blackgates cat as this gives all the ME data on there back page.I can send you all the dsts that I have if you all of my dataif you are interested.

kiind regards and keep up the good work
Bob

Garry's pic's have got in the way of this thread

... On what device/operating-system/browser ?

MichaelG.

Hi Dave , YES please like many others mine are getting a bit tatty

Ken.

I'm definitely up for this, especially BSW/BSF tpi for identifying old bolt threads etc

Hi There

A reader has complained to the Managing Director that 80% is an incorrect percentage of engagement for threads. Despite that I explained how to calculate different percentages of engagement.

What are your opinions on percentage of engagement for ME threads as used for boiler fittings.

regards David

I use the following :**LINK** just copy and paste what you want. hope this helps. Bob sorry for the layout ,I can't get the return key to work when posting

David

Tubal Cain recommends 65% engagement up to 3/8 and 70 - 75% thereafter in the Model Engineers Handbook but that is not specific to boiler fittings. There is also a table for the % engagement for different materials that ranges from 50% to 75%. The only mention of a figure above this is 85% when tapping sheet steel when the thickness is less than the core dia of the thread. (I believe these are recommendations for use in the home workshop and not those used in production engineering).

Hope that helps

Much as I support & welcome Daves idea for inclusion of charts; look in Roebucks 'ZEUS' pocket book (usual disclaimer).. available on flea bay etc, it has everything you would need .. tapping sizes, drill coordinates for jig boring, trigonometry, tapers, BS 4500.A ISO hole & shaft fits, etc,etc. The latest version I have.. metric revision, now includes - symbols & abreviations used on Engineering Dwgs, Misc' function words from USA-EIA standard, G code addresses for NC, letter addresses used in NC..

Cheers

George

Hi David Clark

Good to see you back in the shed......

If you do decide to include charts How about plasticising them so that they keep clean. It would cost more but maybe the advertisers could use the back (Only please). Would that earn enough to pay for them? IF so you could make it a regular feature.

Cheers
John

Edited By John McNamara on 06/06/2013 13:42:27

G'day

Although this is not a chart (of which I love the idea), it is a really good unit converter. Lol, it even does light years to millimeters. **LINK**

Regards from the land of the kangaroo

Cu Later * Danny M *

Interestingly, I've just checked my rather old (1976) version of ZEUS, and calculated that its recommended tapping drill sizes are based on an approx 80% thread engagement.

Make of it what you will.

Gary

I went on google images, loads of conversion chart on there, pinted them off, laminated and hung on a nail in my workshop, like these

**LINK**

DC, I would say 80% is a good idea for boiler fittings as there is a risk of the crests being burn/scorched away during soldering so having the larger engagement will "ensure screw threads are of adequate depth to maintain sufficient strength" as required by the regs.

J

Having got used to metric taps which have different top diameters for each (taper, second, plug) tap, I now use a much bigger %engagement (80-90%) for metric threads. For other threads (where all my taps have the same top diameter) I generally use one number drill smaller than Tubal Caine recommends.

Neil

Hi There

I remember Zeus as 80% and thought it would be a good idea especially for boiler fittings.

The days of assuming a model engineer needs a large hole so he does not break a tap are long gone.

regards David