Jap Threads For Taps Etc

[Tony jinxy froude]

Hi guys, does anyone know what taps i need for jap threads ? ive got a tap & die set which is pretty good quality, but they never seem to fit good clean threads, they always seem to be slightly out, it would be good to get a set that i can use on the mk1. any help appreciated, cheers, Jinxy

[Jim-SR]

they just use metric. common sizes are M6, M8, M10 and M12. in 1.0, 1.25 and 1.50mm pitch. if youve got all of those youll have the majority of threads covered

ideally you want 3 types of tap for each, a tapered cutting tap, a plug tap to use after the taper tap, and a bottoming tap which should be used to clean up existing threads (or to finish cut threads that need to reach the very bottom of a hole), or a plug tap can be used.

if you got taper taps and plug taps in all those sizes, that would suffice

[Tony jinxy froude]

Cheers JIm, im pretty sure ive got all those taps, but not sure in the pitch sizes, are those pitch sizes specific to Jap threads ? ive got taper taps & plug taps in the set i have by the way, can i buy those pitch sizes commercially or are they special order ? cheers, Jinxy

[Jim-SR]

theyre the most common metric thread pitches around, in all countries. if youve already got those taps then im not sure why youre having trouble with them. my only thoughts (without wanting to be condescending, as im sure you know what youre doing anyway) are that youre using the wrong thread pitch taps for the job?

are you having trouble getting the thread started at all? or is it going in alright, but just feels a bit tight? or is it mashing the existing threads up a bit?

aluminium can often be nasty to retap as it corrodes, distorts, etc over time. and steel can be the same if its corroded or dirty. but generally once the tap gets started it shouldnt be too difficult to go down, and should cut clean threads exactly where the existing ones were, or just clean up mildly dirty threads

[Ja99a]

Only thing you might have problems with will be the pipe threads, for some reason they use all manner of pipe threads BSP and wot not.

[Tony jinxy froude]

I think your right Jim, the sizes of taps seem to be right, but the pitch sizes are off as most of the ones ive got seem to mash the threads up, what i think i'll do is get some more taps in the common sizes i use, but in the pitch sizes you gave me up there ^^ then that should sort it. Thanks for all your help, now off to ebay to see what i can find :), cheers, Jinxy

[Paul Woods]

this is the thread specs on all toyotas....

m6 bolts have 1.5mm pitch
m8 bolts have 1.5mm pitch
m10 bolts have 1.25mm pitch
m12 bolts have 1.25mm pitch

[Tony jinxy froude]

Oh well done that man !!, between you guys ive got all the info i needed, wouldnt get this on IMOC eh Paul :), they'd have me off to buy a new car to fit my existing taps !!!! :) :) cheers lads, Jinxy

[Tony jinxy froude]

Paul, can i ask you how difficult it was for you to buy those taps in those sizes, im having a hell of a job finding them in the sizes you gave, all i need is 4 single taps rather than buy yet another tap & die set, cheers, Jinxy

[OlberJ]

this is the thread specs on all toyotas....

m6 bolts have 1.5mm pitch
m8 bolts have 1.5mm pitch
m10 bolts have 1.25mm pitch
m12 bolts have 1.25mm pitch

That's golden!

I'll add it to the weights/measurements thread. :thumbsup:

[Tony jinxy froude]

Great idea !!:), Jinxy

[GaryA]

http://www.mackay.co.uk/webstore/acatalog/861.html but not cheap

[Jim-SR]

try any good bolt and tool supplier. most major towns and cities have one (or several in some cases). theres 2 or 3 within 20 mins drive of me that would sell them, and if they didnt have specific sizes in stock, they could order them within a couple of days.

the only key thing is to try and avoid buying cheapo taps, as they just dont cut as nicely, and lose their sharpness easily. its worth spending a bit more if you use them fairly regularly, especially on steel!

[Tony jinxy froude]

this is the thread specs on all toyotas....

m6 bolts have 1.5mm pitch
m8 bolts have 1.5mm pitch
m10 bolts have 1.25mm pitch
m12 bolts have 1.25mm pitch

Sorry to resurect an old thread ( no pun intended :) ) but Paul are you sure the M6 size is correct, ive been searching everywhere to get an M6 1.5 pitch thread & cant find one anywhere, are you sure its not a 1.0 ?, any help appreciated, cheers, Jinxy

[Paul Woods]

tony if you lay an M8 bolt alongside an M6 and interlock the threads that will tell you if its a 1.5 pitch or not... i will double check today also.

[Gary Symons]

Yep, pretty sure that toyota would use m6x1

Standard metric fine/course threads below:
http://www.metrication.com/engineering/threads.htm

[Tony jinxy froude]

Yep, pretty sure that toyota would use m6x1

Standard metric fine/course threads below:
http://www.metrication.com/engineering/threads.htm
Cheers for that, it does indeed look like it should be a 1.0 thread no wonder i cant find an M6 1.5 tap. Woodsy's been telling becky things are a different size for years :) :).... Jinxy

[Poohbear]

The following is a thread size table out of the back of the MK2 manual for reference.

http://www.twobrutal.co.uk/forum/images/recovered/2008/02/54.jpg

Bob

[Tony jinxy froude]

That confuses things even further, Paul states the M8 thread is a 1.5 pitch, that table shows it as 1.25 pitch, Paul did confirm today that the M6 Pitch is indeed a 1.0 pitch so thats cleared that one up :) Jinxy

[supersi]

Use a pitch measure on the threads of the bolt to work out what pitch it is. I've always got one with each tap and die set I've bought.

[Jim-SR]

That confuses things even further, Paul states the M8 thread is a 1.5 pitch, that table shows it as 1.25 pitch, Paul did confirm today that the M6 Pitch is indeed a 1.0 pitch so thats cleared that one up :) Jinxy

JIS standard is M8x1.25 but i expect there are some M8x1.00 threads as well. it depends on where the bolts are being used. generally anything that is structural and uses a nut will be a fine thread, anything that threads into a casting will be coarse, and everything in between is anyones guess lol. Toyota use some messed up bolt specs though, they tend to stick with JIS for most things but throw in the occasional ISO standard thread as well

the list Poohbear has posted above is all JIS thread pitches, 99% of Toyota bolts will stick to those

[Tony jinxy froude]

Cheers Jim, Ebay is such a wonderful thing :) !! i managed to get a set of 3 x M6 1.0 taps, 1 x M8 1.25 tap, 1 x M10 1.5 tap & 1 x M12 1.5 tap & a nice ratchety type t-bar tap handle, ive tried most of the taps & all seem to do what i wanted them to do which was to clean out existing threads, ive got a few taps & dies in a set but its nice to have a set specifically for the MK1, cheers again for all the advice chaps, Jinxy