Marlco Thread Measuring Parallels

[Ken StraussParticipant @kenstrauss65445]

[Ken StraussParticipant @kenstrauss65445]

I have a set of Marlco thread measuring parallels (US sizes) but no manual. There was a posting years ago (https://www.model-engineer.co.uk/forums/postings.asp?th=49467) that included a link to the manual but that site is no longer active. Where can I find it now?

[Michael GilliganParticipant @michaelgilligan61133]

Ken,

As the provider of aforementioned link, I thought I should at least try:

Here's the product page from WDS's own site: **LINK**

http://www.wdsltd.co.uk/product/4301/marlco-thread-measuring-parallels-unifiedus-national-wds-6603/

It may be worth contacting them.

MichaelG.

.

Edit: There is a brief description of their usage, on p48 of this PDF

https://www.ddbarry.com.au/assets/data/wds/wds_broaching_production_equipment.pdf

… probably all you really need.

Edited By Michael Gilligan on 04/07/2018 07:09:30

[Ken StraussParticipant @kenstrauss65445]

So the pitch diameter is simply Y-X? Thanks!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ken Strauss on 04/07/2018 13:37:40:

So the pitch diameter is simply Y-X

.

… Which probably explains their not-inconsiderable cost.

MichaelG.

[Ken StraussParticipant @kenstrauss65445]

The patent number for the Marlco thread gauge tool is 555830 and was patented in 1941. This patent is available online at https://worldwide.espacenet.com/publicationDetails/biblio?II=9&ND=3&adjacent=true&locale=en_EP&FT=D&date=19430909&CC=GB&NR=555830A&KC=A

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Ken Strauss on 04/07/2018 15:38:45:

The patent number for the Marlco thread gauge tool is 555830 and was patented in 1941. This patent is available online …

.

Thank you, Ken

… I am a great fan of patent documents !!

MichaelG.

[SamsarandaParticipant @samsaranda]

For those who desire to check thread measurements you don’t need the Marlco items, any size threads can be be measured using wires of the appropriate sizes and calculating the micrometer readings that need to be achieved, a lot of maths involved but a very accurate way of sizing any thread, only male threads of course, no it’s not discriminatory it doesn’t work for female threads.

Dave W

[JohnFParticipant @johnf59703]

Looking at the Marco system it’s the same as a thread micrometer with interchangeable anvils but of course you get a direct reading with a micrometer.

John

[Ken StraussParticipant @kenstrauss65445]

Thanks for having solved my Marico usage question. For added points, is there a similarly clever tool to accurately gauge internal threads (not plug gauges)?

[Michael GilliganParticipant @michaelgilligan61133]

Here's a little light reading for you, Ken: **LINK**

http://www.npl.co.uk/upload/pdf/screw_gauge_booklet.pdf

MichaelG.

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