Drilling main jets

If I was to size my own jets ,what size drill bit would I need for a 117.5 jet?

The smallest drill bit I have is 1/32 of an inch and it does not fit in a 117.5 Jet. Good luck finding a smaller drill bit. Z1 enterprises sells these jets for $2.00 each.

GregZ wrote:

If I was to size my own jets ,what size drill bit would I need for a 117.5 jet?

I seem to recall the jet number relates to the area of the hole. You have to calculate the diameter and then look up the numbered drill set (standard size). I don't recall the exact formula, I think there are sizes for both English and metric.

I actually went through this a while back, and here is what I remember:

There are more jet sizes than there are standard drills to make the holes to create all those sizes. Ergo, jet makers have a bigger drill set than anybody else and you won't be able to get all the sizes like they do using a standard drill set.

sean5775 wrote:

The smallest drill bit I have is 1/32 of an inch and it does not fit in a 117.5 Jet. Good luck finding a smaller drill bit. Z1 enterprises sells these jets for $2.00 each.

The really small drills come in the numbered series, not actual diameter sizes.

I agree jets are so cheap you just buy a bunch and go for it. save the extras, you'll have them if you buy new headers or air pods.:laugh:

bountyhunter wrote:

sean5775 wrote:

The smallest drill bit I have is 1/32 of an inch and it does not fit in a 117.5 Jet. Good luck finding a smaller drill bit. Z1 enterprises sells these jets for $2.00 each.

The really small drills come in the numbered series, not actual diameter sizes.

I agree jets are so cheap you just buy a bunch and go for it. save the extras, you'll have them if you buy new headers or air pods.:laugh:

I actually went and tried and I do have lettered and numbered drill bits, about every size available and the smallest bit I had was 1/32 of an inch and that was slightly too big to fit through a 117.5 Jet.

If you want really small drill bits you need to look for "Wire size". I know they go down to at least .0125 (Wire size #82), Grainger has them.

MSC has them down to at least .0059" (Wire size 97), is that small enough?

Whoops! Found one even smaller, .0051".

Search for "Micro drill bits" at MSC.

Kept looking at MSC just to see how small they go, found one .0019", if you need one smaller than that you're on your own

Make sure you properly bevel the jet after drilling otherwise the flow of gas will be a splatter and not diffused. I don't think much of jet drilling for this reason.