# Exhaust bolts

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Ben trying to accurately measure the hole spacing of the exhaust bolts on an B12 head , due to old age wonky eyesight, hangover and the cold I gave up!!!!!!!!!

Anyone know for sure how many millymetrics it is please chaps???

Merci beaucoup

Looks like 59mm

That’s why I asked, to me it looks

like 58 mm, to my mate 59ish

I need an accurate measurement!!

Ok so let me rephrase

I took the time to measure

It measures 59mm

If you're trying to eye-ball it center-to-center with a pair of calipers, I can see why you're having problems

Just screw a couple of studs into the bolt holes, measure across the outside of both studs, then subtract the diameter of 1 stud.

You now have your center-to-center spacing perfectly

1 hour ago, Devilman said:

If you're trying to eye-ball it center-to-center with a pair of calipers, I can see why you're having problems

Just screw a couple of studs into the bolt holes, measure across the outside of both studs, then subtract the diameter of 1 stud.

You now have your center-to-center spacing perfectly

Which is still 59mm

9 hours ago, Joseph said:

Which is still 59mm

Sure is...

However I was simply providing people with the means to figure it out accurately and reliably themselves should they want to

Edited by Devilman

Well mine must be special then I did a test piece at 59 mm before making the new tool, and the spacing is wrong

so I did one at 58mm and all is well

what you making Garry ?

Edited by TonyGee
On 12/3/2022 at 8:36 AM, Devilman said:

If you're trying to eye-ball it center-to-center with a pair of calipers, I can see why you're having problems

Just screw a couple of studs into the bolt holes, measure across the outside of both studs, then subtract the diameter of 1 stud.

You now have your center-to-center spacing perfectly

I've always found less math to be easier. Measure from the east side of 1 to the east side of the other & be done.

And 58, it is.

Edited by slayer61
19 minutes ago, TonyGee said:

what you making Garry ?

I reckon thats a snapped stud driller thingiemajig

Like mine but posher

20 minutes ago, davecara said:

Like mine but posher

That’s the kiddie, been meaning to make one for ages

23 minutes ago, fatblokeonbandit said:

That’s the kiddie, been meaning to make one for ages

I found a spot weld drill was good for flattening the top of a snapped stud, you get to drill it proper then with no slipping

Good idea

ive had good results starting off

with a lathe centre drill

1 hour ago, fatblokeonbandit said:

Good idea

ive had good results starting off

with a lathe centre drill

Must have a hell of a swing on your lathe to spin a whole engine round

1 hour ago, davecara said:

Must have a hell of a swing on your lathe to spin a whole engine round

Cracked me up !!

2 hours ago, davecara said:

Must have a hell of a swing on your lathe to spin a whole engine round

I want to know how you're going to hold it in the chuck !

12 hours ago, slayer61 said:

I've always found less math to be easier. Measure from the east side of 1 to the east side of the other & be done.

And 58, it is.

While fundamentally I agree, in this particular case what you suggest is unlikely / unable to be used.

Calipers cannot measure from "inside" to "ouside" on the same part in the manner you suggest.   They measure outside-outside OR inside-inside, so either way you gotta do some math

Oh yes they can ! Use the depth guage bit, caliper end against one side of 1st hole and depth bit to corresponding other side of other hole - easy!

I do it Devilmans way. Easiest!

On 12/5/2022 at 8:20 PM, Devilman said:

While fundamentally I agree, in this particular case what you suggest is unlikely / unable to be used.

Calipers cannot measure from "inside" to "ouside" on the same part in the manner you suggest.   They measure outside-outside OR inside-inside, so either way you gotta do some math

Caliper? What is this "caliper" thing, of which you speak? I build with a tape measure !!!

26 minutes ago, slayer61 said:

Caliper? What is this "caliper" thing, of which you speak? I build with a tape measure !!!

now thats old school  got to be better than a knotted rope

41 minutes ago, TonyGee said:

now thats old school  got to be better than a knotted rope

Or a pen knife open & shut!

There's few things you can't measure accurately enough with the length, width and diameter of your finger(s).

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