Imperial thread

[inchpincher]

Need to get a t-slot nut for my multifix quick change tool post... It's Swiss, the thread measures 15.63mm/0.613", using a whitworth thread gauge the match appears to be 12(tpi?)-1/2"-9/16".

Imperial confuses me, my Zeus book says a 12tpi whit worth should have an OD of either 0.5" or 0.56". What am I doing wrong?

Thanks,

Ben (born post decimal, and yes I appreciate the irony of my username )

 

[shenion]

5/8-11 is a standard thread in the US and ANSI. I picked up one an the diameter of the threads was 0.615.

 

[gavuk]

Have you got metric thread pitch gauges ...m16 is 12.7 tpi....5/8 whit is 11 tpi........15.63mm od sounds like 5/8

 

[stormin]

Seems to fit with 5/8" -12 tpi in the unified series (note not UNF)

http://www.efunda.com/designstandards/screws/unified.cfm?start=148&finish=227

I think you're probably better or making a new fixing bolt than trying to get the tap.

 

[inchpincher]

Thanks guys, double checked and it's definitely 12tpi and 5/8. I was hoping I have a tap because I have boxes and boxes from tool job lots but no joy. I'd found a guy on eBay who knocks up these t-slot nuts to fit my lathes compound rest, he just asks for the tool post thread details, let's see if he's got this one, lol

Cheers,

 

[ford34/2]

threads

quite strange,all standard:: ( in the good old days )
9/16 X 12 UNC
1/2 X 12 WHIT
9/16 X 12 Whit
3/4 X 12 BSF

but a good nut and bolt supplier should help you no end.a continental manufacturer maybe just used what they fancied!!!!
Guessing you looked very carefully at 15 X 2 and 16 X 2 metric?? metric 2 pitch is so close to 12 Gauge, pitch gauge def into threads??

Stan

+ Tracy tools, sadly no 5/8 X 12 listed::
http://www.tracytools.com/

 

[ford34/2]

Metric???

Just been playing round with the scrap bits, I have some stainless studding, 16mm

OD is 15.65 and pitch is 2.0, so its 16 X 2.0
now a metric pich gauge 2.00 fits tight and snug , a whitworth 12 is so very very near but wont bottom out into the threads, My thoughts are you def sure its 12 whitworth and not 2.0 metric??

I`d be very tempted to source a 16 X 2.0 metric nut and try it.( or I may be able to send you one --- if it fits weld it into a plate??)

Stan

RDG are probably cheapest on a set of 16 X 2 taps

 

[stormin]

An M16 metric thread would make more sense seeing as it's of Eurpoean origin. Threads could possibly have been stretched by over tightening over the years.

 

[Hitch]

Go steady, M16 x 2 will screw into a 5/8"UNC nut, about 4-5 turns, then the difference in the thread catches up....and goes tight.


Id think it would be 16x2 being european?

 

[graffian]

when you say 12tpi fits, is that a perfect fit with a gauge? Even a small amount out on the pitch is usually really obvious with a gauge, the difference between 12 and 12.7 should be really obvious, 13tpi gauge should be a better fit. 15.63 diam could easily be either 5/8" or 16mm thread.

 

[ford34/2]

Update

Update::
I had a PM with some pics from Ben, the pics confirm his original whitworth 12 TPI theory. Sadly 2.0 metric doesnt fit. this was my reply::

Now thats not what I wanted to see, dont suppose some daft so and so could have screwcut a modified thread on the existing shaft,
so,other than screcutting one, even making a bung and welding it in, not too sure what to suggest, as your pic confirms, certainly looks 12 gauge whitworth, I think that was 55 degrees, and metric is 60.
is there sufficient meat on the shaft to drill and insert a threaded stud, maybe12mm.
Stan