[graemeian]

I need to make M25-1 H6 female threads using a thread mill. I looked on a chart and it specifies that the Major diameter be 25.314. Do I make the bore 1mm under or use the minor diameter of 24.15 or something else? I have previously used the tap drill size that in this case would be 24 I would guess.

[deadlykitten]

there are tolerances for each dimension. If you wish, i will share them

[Superman]

The H6 specifies the tolerance band that the internal diameter, pitch diameter, Major diameter even the root radius must all be between the sizes given. It sounds that you are familiar with tolerance specs.

I would suggest that it would be easier to make an external thread to h6 tolerance (as a "go" gauge) then you would know that if it goes into your nut "smoothly", then you should be very close.

Measuring an internal pitch would need specialist instruments ( read this as also $$$). More common to find external pitch micrometers (mm or ") in a general workshop.

[graemeian]

That would be great of you could send them for my reference.

[deadlykitten]

m25x1 6H
cilinder, diameter before threading 23.917 ... 24.153
thread, flank diameter 24.350 .. 24.520

I looked on a chart and it specifies that the Major diameter be 25.314

for a M25 female thread, thus a nut, there is no standard tolerated dimensions > 25, thus wherever you found 25.314, that is a not a practical guide, but more theoretical

if you wish for more infos, pls share that chart / kindly

[deadlykitten]

amesweb.info/screws/metric-thread-dimensions-calculator.aspx

there is an online calculator; for your thread, choose 'custom use', as shown in attached, otherwise only standard thread data will be available

please notice that it shares more infos for the shaft, and less for the nut ... this is normal, and there is no 25.314

i am ok with such infos, know also how to link them to tooling and custom control, etc, as i was schooled by a woman from threads tools factory

please, feel free to ask anything / kindly

[Superman]

Remind me Kitty to never have you make something for me that calls up a standard

Graemeian... everything is tolerance. My specs from a Machinists handbook 30th ed does not specify M25x1.0p
Have attached external & internal specs for your thread size

[deadlykitten]

if i may, that 30th edition, is a resume for common tolerances, public document; you can aproximate 20 to 25 with some differences that are ok for machining, but not ok for more accurate proceses, like when crafing gauges; for example, factory control does not inlvolve only go & no-go gauce, thus not only 2, but 6 or 8, thus there is a very good control for marginal dimensions, if the client demands so ...

everything is tolerance

that's not true for common nuts; for example, as for 25.314, i can share 8 values, based on different method of calculation, different standards

a common shop can not control such a dimension, thus the root diameter of a thread/nut is too expensive to check; but it is not for more accurate industry, like aeronautics, where, also the tolerances for the nut root are tighter, as to be sure that a minimal radius exists so to avoid a sharp corner, and still ensure the assamble will work, while in common shop this is less important; there are gauges only for nut-root, they don't make contact on flanks

such control is too much for regular shops; even if you see a value in a table, this does not mean that you can reach and control it; for regular use, nut root diamters are no longer tolerated, or at least not as much as they used to be, and factory documents have such recomandations; what happened next, is that thread insert manufacturers aligned to the public standard, and the full profile insert showed up, for common clases like 7h 6g, etc

Remind me Kitty to never have you make something for me that calls up a standard

i don't have to you are regulary reminding you that ... maybe you are in a loop ?

[Superman]

Fair enough Kitty...
But I would stick to a piece of paper that references a standard, and how it is applied ... than a Web app that just puts numbers on a screen.
An aerospace company would laugh at you and just say your parts are non-compliant, and the best location for them is in the rubbish skip along with the swarf.

[deadlykitten]

the app is less important, but to verify the data

what i shared is from a mini database, that i created few years ago, with values from standards, and then i searched for an on-line site, and compared the values, as to sugest it to graiemen, being simple

i also have trendlines, to aproximate marginal tolerances, etc ... and other things

ps : your hand writing is astonishing

[Superman]

ps : your hand writing is astonishing

My fans would go mad, if I put up my pic. ????

[John-cbn]

Hello, we are manufacturer of cbn insert from China.
We can give you advice about how to choose insert.
Welcome to enquiry.
Whatsapp: +86-18282557341
E-mail: [email protected]