Bolt sizes

mengele

I need to drill out and retap in new treads. The old treads were for a 13mm bolt. What's the next size up with. I know the next most common is a 17mm bolt but is there something inbetween

DBK1

mengele wrote: »

I need to drill out and retap in new treads. The old treads were for a 13mm bolt. What's the next size up with. I know the next most common is a 17mm bolt but is there something inbetween

By 13mm I assume you mean that’s the spanner size?

If so then that’s an M8 bolt. To measure a bolt you measure the diameter of the threads, not the spanner size. The next size up is an M10 which takes a 17mm spanner. There’s nothing in between that in a metric. If you go to imperial the only size in between them two would be a 3/8” which is about 9.5mm. It wouldn’t be much smaller than the M10 really.

cjpm

I presume you are referring to the size of the spanner required.


The next size up is an imperial bolt with a 9/16 head or failing that 5/8 head







M8 bolts usually have a 13mm head
M10 is usually 17mm and

M12 is usually 19mm

mengele

Sorry yes I was talking spanner size alright. Will have to jump to the 17 spanner size bolts so

kollegeknight

mengele wrote: »

Sorry yes I was talking spanner size alright. Will have to jump to the 17 spanner size bolts so

Do you know much/ anything about tapping a hole? Are you sure the treads are totally gone?

What has to be tapped?

_Brian

You’d be surprised what dressing a thread with a tap can do without drinking it out. It cleans off damage and debris from the existing threads.

If moving up a bolt size is a problem you can fit something like a helicoil and that will retain the size

Suckler

Is welding in a nut an option?

vincenzolorenzo

Helicoil might be the job for you. Or if you have to go up use a socket head bolt if space too tight to fit 17mm hex head