Odd metric thread call out 1

[cwdaniel]

I have a M10 x 1.1 6g thread to call out on a drawing.
Has anyone seen a chart with major/minor/pich diameter tolerances for such a thing?

 

[pmarc]

I was only able to find a chart with M10x1.12 6g.

http://www.fixingsupplies.co.uk/Metric2.pdf

1.1 pitch is not a standardized value.

 

[cwdaniel]

Standard or not, doesn't change the part I'm reverse engineering that has a 10mm thread with a pitch that fits a 1.10 thread gauge perfectly.

In the meantime I did find a trial version of software that accepted a 1.10 pitch variable. Don't know how to verify the results though.

http://closetolerancesoftware.com/METhreadPal.html

 

[ajack1]

Is it possible that on the original drawing the setting was to one decimal place so it defaults to a 1.1 pitch instead of 1.12?

Whilst it might look perfect on a thread gauge what state is the thread in? If it is worn or stretched the difference between 1.1 and 1.12 (0.0007”) would be fairly hard to see using a thread gauge.

It is hard to think, but obviously not impossible, that someone would go away from a standard thread to increase the pitch by only 0.02mm, assuming all the form is standard.

 

[CheckerHater]

The thread M10x1.1 doesn’t exist.
In fact, metric pitch 1.1 mm doesn’t exist.
Are you sure you are not dealing with British Standard Pipe Thread 1/8 28 threads per inch?

 

[cwdaniel]

Not 28 TPI. The thread is in good condition and I have more than one example of it. I don't have a 1.12 gauge to compare it with, but we do have 1.10 gauge that fits it. It's not a big surprise that this Japanese equipment mfg. would create parts like this.

 

[CheckerHater]

Is part in question some sort of hydraulic connector?
Japanese use both British-style threads and metric; in fact you can even assemble M10x1 with G1/8 if you try hard.
It still blows my mind that you managed to get 1.1 mm pitch gauge somewhere.

 

[cwdaniel]

It's a screw for fine adjustment of a grinding table. We took the part for inspection on an optical comparator. Inspected at 1.10mm pitch and the shop had a the gauge to verify it. We went and bought our own gauge - Starrett #156M. We were surprised that it was readily available.

 

[CheckerHater]

Fascinating.
If it is for fine adjustment, makes me think of something exotic, like “microscope thread”, but I am not very familiar with those.
You mentioned optical comparator; did you have a chance to verify thread being 60 deg and not 55 deg?

 

[cwdaniel]

Not exotic, but a wafer grinder is fairly precise in the adjustments.

I didn't do the measurement, and form angle wasn't brought up. If it was other than 60 I'm sure it would be mentioned but I'll verify that. I don't see how that would effect the pitch though. Unless there's a standard M10x1.1 55deg angle?

Never heard of a 55deg thread form

 

[CheckerHater]

British threads derived from Whitworth threads are 55.
I brought "microscope" because some of them combine metric OD with threads per inch pitch.
1.1mm pitch was used on outdated Lowenhertz presision thread, but with 7mm dia.
You can find few threads to look at here:

http://www.gewinde-normen.de/en/index.html

Good luck!

 

[dgallup]

You can use the metric profile with any pitch you want. Everything is defined as a percentage of the pitch and the angles are always 60 degrees. Take a look at Machinery's Handbook, everything you need is there.

Now where in the world did you find a 1.1 pitch thread gauge?

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[drawoh]

cwdaniel,

A 24UN thread has a pitch of approximately 1.06mm.

Could this be a 0.4-24UN thread?

How about a 10mm-24UN thread?

JHG

 

[cwdaniel]

dgallup >
Got the handbook and could come up with the numbers if I actually knew what class the parts were made to. Given the unsualness of this thing I don't want to assume it's "preferred"

Got the gauge here:

http://www.starrett.com/metrology/product-detail?k=156M

chckerhater >
Thanks. I missed the BSPT and whitworth 55deg thread form.

All this discussion sent me back to the inspection table and I measured the travel distance between the mating parts through 180deg rotation. .042-.043inch leans me to the 1.10mm pitch still.

I think we will order thread wires for both 1.10 and 1.12 pitch and try verify further.

 

[cwdaniel]

drawoh>
Non of the TPI gauges in the range fit completely.

 

[KENAT]

It could be a 'special' just like you can get UNS threads.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[juergenwt]

Do you have the original manual print or just the screw? Maintenance people are known to replace M10x1 with 3/8-24 (if you are in the US). I would try a M10x1 screw. Can't count the 5/16-18 screws jammed into a M8 thread.

 

[cwdaniel]

No print, just the part. And it's more than a basic screw. No chance of a lazy substitution