View Full Version : Imperial Thread Equivelent of Metric M5

02-12-2005, 11:57 AM
just a quick question I hope.
so i can find the tap and set my lathe up fast....doing the job tomorrow ..shops are closed
what's the nearest thread to m5 in imperial.
and tell me how many tpi.
dont fancy messing around with change gears on my lathe and need to cut three studs of around about 5mm M5.
they can go up to 5.5 mm in dimeter max.
all the best..mark

02-12-2005, 12:08 PM
5 (mm/thread) / 25.4 (mm/in) = 0.19685 in/thread
1/0.19685 = 5.080017 tpi

Regards, Marv

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02-12-2005, 12:09 PM
Try this website.


Spin Doctor
02-12-2005, 12:40 PM
Thank's Marv, bookmarked that one into the Research Folder on my favorites

02-12-2005, 12:46 PM
Hi Mark,
I if the metric thread is standard, that would be 5 m/m dia (.1969") x .8 m/m pitch (.0314), then the closest would be a 10/32 thread, 10 = .190" dia 32tpi(.0315") The next size up would be a 12/32 thread 12 =.216" dia.(5.5m/m) x 32tpi (.0315")
The above are UNF threads or do you mean BSF, or BA threads
BSF= 3/16"dia. x32tpi 55°
BA= #1 (.2087"dia. x 28.2tpi(.90m/m P)47-1/2°


[This message has been edited by vmil3 (edited 02-12-2005).]

[This message has been edited by vmil3 (edited 02-12-2005).]

Allan Waterfall
02-12-2005, 01:01 PM
3/16" BSFor M.E. if you've got the taps and dies.

[This message has been edited by Allan Waterfall (edited 02-12-2005).]

02-12-2005, 02:13 PM
Thanks guys for the info .
think Allan /Doug has it closest to what I want to do
I've got the taps for the hole it's going into.....I think I've got 3/16 bs
Cant find my thread tpi guages.
dont think I've got a die for 3/16
so thread will have to be cut on the lathe
will have a go tomorrow......wish me luck as this is only the second time of cut threads .......first time turned out well though.....made some bolts for my bridgeport raiser block, the one at the top is my first attempt ever at screw cutting ..
the others three turned out ok.
think that my lathe is very good letting me do so well for a first attempt.


Do you think I'm being ambitious at trying 32 tpi on such a small job....and this being only my second attempt at screwcutting.
I will be using 5c collets in the chuck.
any tips on doing this small thread much appreciated.

all the best..mark

Allan Waterfall
02-12-2005, 03:17 PM

3/16" BSF thread depth is 0.020".
All BSF and Whitworth thread depths are 0.64 divided by TPI.

If you haven't got a die,tap a short stub and use that to check your threads.

Just lately I've been cutting my threads by the straight in method.For me it's giving a better finish than than twisting the top slide over.I haven't had my topslide fitted for months,except to turn a taper using the taper turning attachment.
My tools are just mounted on a toolblock bolted on the cross slide with four bolts,a lot more rigid that way.

I usually run a fine file on the crests whilst the lathe is turning after the last cut,then just run the tool down again to clean it up.


[This message has been edited by Allan Waterfall (edited 02-12-2005).]

02-13-2005, 08:15 AM
See page 32 of http://users.rcn.com/sas.ma.ultranet/sizes.pdf

Alistair Hosie
02-13-2005, 10:16 AM
thats good screwcutting for first attempt "very good" well done Mark Alistair