Where's the best place to get a set of pin gauges for checking jets, IRF and other carb tuning items?

MSC Industrial Supply

amazon

I'm guessing a .011-.06 kit would be good for metering block items like the idle restriction jets, air bleeds, etc and a .061-.250 kit would be good for jets? Never measured any of them before, so what sizes should I be looking for?

That's what I have

eBay is good

eBay

Ebay...

Drill bits or pin gauges, check every one you use with a micrometer to see what size it really is, not what it's supposed to be.

I also suspect that some import pieces are the closest metric size, rather than the correct inch size, based on some of the variations in measurements I've found.

This.

but remember one thing. a "xxx" size drill or pin will NOT fit in the same identical size "xxx" hole. that requires a press fit.the pin or drill MUST be a couple of tenths undersize to fit the hole. just machining 101. also, watch the edge of the pins when getting close to your hole size determination, as it is easy to get the sharp radius of the pin end to cause a gouge if started crooked in the hole being measured.

^^^ good stuff! (I needed that info).

I bought a small pin/drill set,but when I measured with digital caliper I found there several that didn't measure what they were supposed to be

I have a pin drill set, 61-80, (.0135-.039), and number bits along with fractionals. I've used these for pump squirters, air bleeds, jets, oil restrictors, etc on all kinds of stuff. Personally have never needed anything more precise. Don't forget the pin vice.

Amazon or eBay. Pin gauges usually come in plus or minus sizes. The most common is minus and that is what I use.

99% of the time a drill bit will cut a few thousands over the drill size, if you want a precise fit then drill under and then ream the hole for the required size and even then a ream will cut over/under depending on the type of coolant/lubrication used,but usually with-in tenths of being on size.

So when we are talking orifice of an air bleed,how close is close enough.??

I bought a set years ago to use for checking valve guide clearances and for a few other projects

I use my carb drill/pin set and I also mike them all the time. I have found mine to right so far. I have the sets from .008 to .140 and I actually bought mine from the Matco tool man as he found where to get them and got them for me. But that was years ago and you need a tool man who will go out of his way to work with you to get them which I had. Ron

I bought my 2 sets off of ebay.. goes from .011
up to .250.. and yes I mic them every time I
use 1

I'm not talking "a couple of tenths"; I've seen +/- variations well beyond that. And, yes, the bit does need to be SLIGHTLY smaller than the desired hole size.

How closely do you want to track your tune?

my large set is in a wood case. nice set that i bought from a friend. The small set i found on ebay. Pin Gauge your Holley main jets jets. You will be surprised at how different they can be in the same size.

calipers can be "tuned" by how they are used. some have hands that can cause variations just because of how the calipers are held. also, remember this. measuring tools are their most accurate when used at the temperature they were calibrated at. this also includes humidity. so now we need to get into the lab with your part and gauges/measuring devices, wait until both have "normalized", then measure. suuure we will....
my point is, you are getting reference information to allow you to make the best decision possible to use in your particular endeavor. this also apples to engine building as well as spacecraft work, although the work conditions are vastly different between the two.

Legit Holley jets are stamped after determining where they flow in comparison to a specified high/low range for a given jet #. As such, jets that both fall within the same #'s range can have a different hole size, yet still be rated the same.

Holley used to offer some "close limit" jets that were refined in their ratings even more. If you see a #602, that's a #60 that flowed in the middle 3rd of the acceptable range for that size. The BLP and MaxJets are rated by .001"-incremental size and are even more refined.

I bought some Jeg's house-brand jets recently to fill in a couple of sizes I was low on. One size measures slightly smaller compared to the Holley of the same #, but the Jeg's jets have an obvious bevel on the entrance to the hole that the Holley doesn't, so they very well could flow the same. On the other hand, one of the three sets of Jeg's jets isn't even sized consistently between the pair. The smaller one doesn't appear to have been machined all the way thru the hole, so I have zero faith they flow the same, much less that they are rated correctly as a Holley replacement. Don't think that I will be buying any more of those...

I need to fine tune and while tying to get my bleeds in order I have bleeds where you can't see the number or it has none.So I tried to use the pin drill set ti figure outfor instance the 20 #23 air bleeds and nothing I had fit properly in the orifice.Very frustrating to say the least!

A quick update on additional jets I purchased: I was disappointed w/ the Jeg's jets I mentioned buying above, so I bought some additional jets from eBarf which were advertised as Holley jets and used the Holley part # in the description:

"2 PACK HOLLEY CARBURETOR MAIN JETS SIZE 81 122-81 1/4"-32 4150 4160 4500" (Bolding is mine to emphasize their use of Holley name and Holley part #)

The jets that arrived are NOT Holley jets; they appear to be the same QFT/Proform/Jeg's jets that haven't measured consistently, which I wanted to replace with "real" Holley jets.

The full order hasn't arrived, but if -- as I suspect -- they're all "non-Holley" jets, I'm going to be in touch w/ the vendor about it.

Boldin the word size and the discription changes

plus if they fit your Holley carb they are Holley carb jets.I aint sayin its rite but it can be interpreted several ways.either way it still sucks.

Yep, and a customer almost hurt his 950+ BB Chevy dynoing one of my 1150's and when he needed just a bit more jet, he used the Jeg's and LOST power and went stupid lean only to find out the 100 Jeg's jet was WAY smaller that the Holley..............BLP to the front FCK the chinese copy cat crap..........I don't play craps..........

These days, that's a problem with parts for anything you can imagine. They use the words "for" "replacement" "compatible" "fits" etc. Look at the brand name in the description, pictures, and read the ad carefully. Price is the big give away. You can usually pick out scumbags selling this counterfeit trash. If it was sold as genuine Holley, that's fraud. Proceed as you see fit.

Yep...time to ditch all that other crap and convert to BLP jets. I did and I'd never go back to using the other stuff. In fact, I gave all the other jets away.