Umm, simply drilling jets can give unusual results. You can
find that a smaller hole might flow more fuel than a slightly
larger one, because of surface features inside the hole. If
you really want to try, just purchase the drills from MSC Corp,
what size(s) do you need?
Also remember that you will need to get them turning pretty
fast to do a decent job of drilling the hole inside of a reasonable
time, around 10K rpm or so.
A dumore drill press works well for this, even better is a Boley
please reply to:
I probably should have said 'watchmaker's lathe' instead. Boley
is only *one* company that makes/made them, and they are
invaluable for doing small work like drilling a five mil diameter
hole in a brass jet, that sort of thing. The idea is that
the spindles turn at high speed and run on very accurate bearings
I'm not going to go out on a limb here and make the statement that
anyone trying to prototype or reproduce carb jets will not be able
to do so without one (the overall level of resourcefulness of posters
here being what it is) but it makes the job a HELL of a lot
That sort of thing. Seriously. A cursory check on ebay will
show that one could tool up to drill small holes with a used
watchmaker's lathe pretty inexpensively. If you look closely at
the photo of my office at work, you will see a somewhat truncated
boley lathe in the far upper right corner:
I don't use it often, but when I need it it's invaluable, for
modifying miniature rf connectors.
please reply to:
Sets of wire-gauge twist drills from 61-80 are readily available from
the usual online sources, if not the local hardware store. A hobby shop
may have them, exorbitantly priced, no doubt. Most lawnmower carbs I've
seen only have holes in the castings, not removable jets, hence the
need for getting the whole carb. You aren't prepping a Hemi for
racing, after all. Getting AT the jet to drill it out might be a
problem. Drag-racing lawnmowers are we???
Philistine. It's the principle of the thing, not the size of the
motor. You can be sure that the guys who prep the hemis spend
as much time on their *lawnmowers* as with the top fuel machines....
please reply to:
A drill bit is generally just a drill bit.
Now the size..thats another story.
What size(s) do you need?
"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist
I worked at Carter Carburetor in the mid to late 60's. The bulk
of the carburetor jets were made on genuine Swiss screw machines
(with a few Escomatics thrown in). The set-up people and
operators were the "cream" of the machine shop personnel, the
machines were kept in the best repair, and only the best
tooling/materials was used. In spite of all this, it was
impossible to produce jets of a given flow rate although when
checked with pin gages these were identical. The procedure was
to run the parts and then sort the production using high accuracy
I understand that ball point pens and many solid state electronic
components are still like this. You make the parts and sort for
the characteristic of interest, for example line width and diode
I was on the fuel pump side of the Carter operation, but many
conversations with the carburetor technicians about "tuning,"
indicated [and I have seen] in many cases the use of a sizing
drill or reamer to "open-up" a jet 1/2 thou for increased air or
fuel flow frequently resulted in *LESS* not more flow
[apparently] because of changes in the surface finish or raising
a minute burr etc. [There was as many explications as there were
All this is not to say you can't make jets, just that it is some
what of a black art, and you will need some sort of flow meter to
see what you made. This will be even more critical for the tiny
hole sizes you will be dealing with, as you attempt to tweek and
Unka George (George McDuffee)
============================When you give power to an executive
you do not know who will be filling
that position when the time of crisis comes.
Ernest Hemingway (1899-1961), U.S. author.
"Notes on the Next War: A Serious Topical Letter,"
in Esquire (New York, Sept. 1935; repr.
in By-Line Ernest Hemingway, ed. by William White, 1967).
While there are jet drill bits, ordinary jobber's bits can be used if you
take and ease the sides of the bits a bit so they don't cut. Get a full set
of number and metric and inch bits and you'll have a bit for every thou
practically in the sizes used for gasoline jets.
Yeppie, Bush is such an idiot that He usually outwits
everybody else. How dumb!
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