Thread size trimmer metric or imperial size?

no engine told and is and engine question. USA car?
you don't have a set of wrenches to just try them.?
it not metric it is old USA Imperial inches. then....

the bolt is not lost , right?
the mopar parts id #7 shows 0.312"
threaded at 5/16-18TPI ASE .
treads per inch
head size is :1/2" wrench, buy a set be ready next time to try them all?

the HDD is a yankee invention and uses Imperial screw sizes..
INCHES, is that. not METRIC.
so lost the others screws from other HDD removed? (story)
the screws must not be too long or you damage the HDD. ok?
rule1 stated (1/4" max? 6mm long)
they are #6-32 screws (#6 and 32 threads per inch)
see that word inch that is greengo yankee imperial sizes.
but other screws in a PC are metric, but not HDD and not PSU.
a
Toshiba's 3.5-inch P300 Desktop PC Hard Drive

if you want I can link the data sheet to it.
from makers web site in Japan. oops the silly manuals skip this fact, my guess is it will state (hidden) complies to ATX spec,


here is USA data sheet that answers this question
see lower page , words, 6-32UNC and the 0.25" inch LIMIT
note too, the 0.188" side limits on penetrations, ok?


https://www.techpowerup.com/forums/threads/pc-component-dimensions.157239/

the DVD and floppy drives are metric and are japan inventions.
but HDD is ours. USA (Seagate top of the heap) IMO

router bits shaft come in 2 sizes
metric and imperial
using imperial shaft in metric collets may be the problem

measure it.
measure the place if fits, match it. it's metric, not imperial inches.
or call isuzu.
or find a mechanic, he will do the measure and fit it.
all ASE mechanics can to this blind folded.

my guess 8mm.
I can not teach you how to measure things.
I uses 2 tools.
a caliper
and thread pitch gauge.
(or from a box of old metric bolts, trial and error way)

the beauty of imperial measured bolts is that there are only 2 threads for each size bolt
so if it is 7/16 bolt it will be either unf or unc one thread is fine (unf and most likely) and one is course (unc)
however if it is mtd make it could be running metric in which case the bolt will be ( if 7/16) 11.11 mm in which case the thread can be 1.25 or 1.5 or 1.75 pitch
might have to talk to a mower shop that sells mtd and get the size bolt from them

http://www.toolspareparts.com.au/page/shop/browse/a/category/e/black_deckerspareparts

http://servicenet.blackanddecker.com/parts/index?_ga=1.255340872.1578785811.1435894870#5

Die sets are used for cutting and shaping of materials. They generally use a press and a mold that are cutomized for the item they are making.

Oct,11/10,, First you need to know it the item is European or Japanese which all use Metric threads. If it is USA it probably uses Imperial threads which are fine or course. England (British) also have fine and course but not interchangable because thread angles are different. Anything of Japan older than 1967 also uses Metric but not the same metric as 1968 and newer. In 1967 there was a world conferance that was "ISO" international standard organization. Some Metric stayed the same but in small sizes under 6 MM, the 5s, 4s, and 3 were changed and all these have a tiny raised or indented dot to tell you they are the new thread. Some motorcycle parts use special not common threads to prevent you from using a cheap poor qualiy nuts or bolts that might fail when in use ( steering parts or brake parts on a car). Occasionally you might use too long of a bolt or screw and it may extend and break something else. Before 1901 most mechanice were called FITTERS because there was not many standard parts and everything had to be fitted. Henry Ford helped make things interchangable so we call them standard parts. If you could give some rough dimentions of the screw ( 3/16" long by 1/8"...or 5 mm by 13 mm long,,, or other American sizes are size 6X32 or 8x32 and different lengths. This would help. Can you find some old fellow that lives on a farm and he might be a mechanic and can figure what you need. Good luck, EEL

I like this question as it poses quite a challenge! Older Echos have the left handed threads on their crankshafts (and possibly even now)...but the shaft off the gear head would really confuse people who can't remove the head anyway if it was LH and that job in itself is a challenge also. Do you have any hardware that will thread onto it?...never seen an old Toro before! yes, 3/8 24 is a pretty standard SAE size...but certainly the Toro shaft could be close to that and some other size entirely > I hate to think in terms of metric on this.

If your lug is a Metric one try to use an Imperial size one after cleaning the thread.