Thread Size

jeffreykogan

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Mar 1, 2021
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Hi, does anyone know what the thread size is for the shaft bolt on the 78.5cc Predator clone for the Gasbike kit?
Bolt Size.jpg
 

wrench

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Aug 20, 2019
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Could be a 7mm x 1.25 ?
Why did ya need a new bolt anyways?
Lets see a pic of the head of that 1/4" x 24 bolt
There should be markings on it that will identify if its an American bolt or not
 

curtisfox

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Dec 29, 2008
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ya some are so close that they will thread in, i would double check, if wrong could easy strip out..................Curt
 
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wrench

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If it has no markings on the head it's a grade 4 bolt or lower which is weak for what it's being used for
 

wrench

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That's a Metric bolt, 8.8 is equal to USA grade 5

Home depot told you that bolt with 8.8 stamped on it was a USA 1/4" x 24 bolt?
Should of gone to Ace Hardware
 
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jeffreykogan

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That's a Metric bolt, 8.8 is equal to USA grade 5

Home depot told you that bolt with 8.8 stamped on it was a USA 1/4" x 24 bolt?
I went to home depot, and the bolt fit perfectly into the hole marked 1/4-28. No play, and no unnecessary force needed.
 

wrench

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Most hardware stores have a nut and bolt selection guide on the wall.
You bring the nut or bolt with ya to the store and screw it in or bolt it on to find out what size nut or bolt ya got.

Opps ya already did that
 
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wrench

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What do ya think grade 8.8 means? Metric Grade strength numbers on a bolt means it's a metric bolt

USA bolts are not stamped with metric grade strength markings
Metric bolts are not stamped with USA grade strength markings

Go back to the store and see how it screws into 7mm
 

jeffreykogan

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What do ya think grade 8.8 means? Metric Grade strength numbers on a bolt means it's a metric bolt

USA bolts are not stamped with metric grade strength markings
Metric bolts are not stamped with USA grade strength markings

Go back to the store and see how it screws into 7mm
Is 7mm the same as an m7 bolt? I know this question might make me seem a bit thick-headed, but I'm definitely not an expert at bolt sizes
 

jeffreykogan

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Yes it is though it could have more than one thread pattern.
What thread pattern for an m7 would match up with a 1/4" by 28. The 1/4" by 28 seemed to have matched with the bolt that started this whole conversation, but the fact that you say that 8.8 is a metric bolt grade makes me think otherwise.
 

Sidewinder Jerry

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It'd be rare that a any standard or metric bolt and/or nut tread pattern would match though the diameter might be close. M8=5/16", M13=1/2", M14=9/16", M19=3/4" etc.