looking for recommendation on how to drill a 1" deep 5/16" diameter
hole in the end of a steel 5/8" bolt. it is crucial that the hole be
centered and parallel to the bolt axis. i have a small craftsman
drill press, plenty of drill sizes, and a starret auto punch.

the best idea i can think of is to bolt the 5/8" bolt on to the drill
press table and hope the press table is perpendicular to the chuck
axis. got no clue how to find the bolt center so i can punch it.

"Carlos Valor" wrote in message
om...
looking for recommendation on how to drill a 1" deep 5/16" diameter
hole in the end of a steel 5/8" bolt. it is crucial that the hole be
centered and parallel to the bolt axis. i have a small craftsman
drill press, plenty of drill sizes, and a starret auto punch.

the best idea i can think of is to bolt the 5/8" bolt on to the drill
press table and hope the press table is perpendicular to the chuck
axis. got no clue how to find the bolt center so i can punch it.

If you want it done right, find a friend with a lathe. This will only take a
second. I'd do it for a cold one.

Karl

clamp a piece large plate to the drill table

about one inch thick would be fine

drill and tap it for the bolt
use a undersize tap drill and a real sharp tap
might even hone the tap a few thou under size for a tight fit on the bolt


thread the bolt into the hole from under the table
use a nut to lock the bolt in place

drill your hole

will be as centered as practical on that type of machine

be sure to use a good sharp center drill to start both holes

good luck

(Carlos Valor)

with regard to drilling an axial hole in a bolt end

the best idea i can think of is to bolt the 5/8" bolt on to the drill
press table and hope the press table is perpendicular to the chuck
axis. got no clue how to find the bolt center so i can punch it.

You can find the bolt center with a combination square's center head. File the
bolt end flat, then mark it with magic marker before using a scribe and center
head to make crossed lines to pinpoint the center. Punch (the bolt held
vertically in a bench vise), with a prick punch, then punch again with a center
punch.

If you don't have a center head, go to a place that sells them with the marked
bolt and scribe in hand, and do it there.

At the drill press: get a piece of hardwood (2by2by8--or such, whatever's right
for the length of your bolt) that you clamp to the table, in the center so that
the drill will clear the hole in the middle of the table. Drill the wood with a
5/8 drill (or just under if you have it--19/32). From underneath the table,
insert (screw) the bolt up into the hole in the hardwood, and (from the top)
run a nut on the bolt down to the top of the wood. Washers on both ends would
help. Use spacers if there's not enough thread on the bolt (or thicker wood).
Crank the nut down firmly onto the wood.
Change the 5/8 drill bit (without moving a thing in your setup) to first a
center drill, or something small enough to be able to find the center-punched
60 deg indent you made in the bolt end. Then change that drill out for a 5/16
drill (again, without moving a thing in the setup).
Go slow; use cutting oil on the bit.
Frank Morrison

williamhenry wrote:
clamp a piece large plate to the drill table

about one inch thick would be fine

drill and tap it for the bolt
use a undersize tap drill and a real sharp tap
might even hone the tap a few thou under size for a tight fit on the bolt


thread the bolt into the hole from under the table
use a nut to lock the bolt in place

drill your hole

will be as centered as practical on that type of machine

be sure to use a good sharp center drill to start both holes

good luck


The OP didn't say *how* centered and parallel it had to be, or for that
matter the length of the bolt and it's threadrd length. One man's idea
of "crucial" centering may be different than another's.

He might be able to use your idea but beat the cost of buying a tap and
tap drill if he doesen't have them by just drilling a 1/2" hole through
that plate and securing the bolt with a nut on top, or one on top and
one on the bottom, depending on the bolt's thread length.

Heck, he might even beat the cost of a thick metal plate if he doesn't
have any by using a thick hardwood board and some washers under the nut(s).

HTH,

Jeff

--
My name is Jeff Wisnia and I approved this message....

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

yep , several ways to skin that cat

just depends on how nice a pelt you want

On Sat, 11 Sep 2004 18:40:30 -0700, Carlos Valor wrote
(in message ) :

Put a long drill bit or piece of rod known to be straight in the chuck and
use a square to check for perpendicular. Most drill presses have adjustable
tables.


press table and hope the press table is perpendicular to the chuck
axis.

"Carlos Valor" wrote in message
om...
looking for recommendation on how to drill a 1" deep 5/16" diameter
hole in the end of a steel 5/8" bolt. it is crucial that the hole be
centered and parallel to the bolt axis. i have a small craftsman
drill press, plenty of drill sizes, and a starret auto punch.

the best idea i can think of is to bolt the 5/8" bolt on to the drill
press table and hope the press table is perpendicular to the chuck
axis. got no clue how to find the bolt center so i can punch it.

Here's a trick that I've used with some success, put the bolt in the drill
chuck ! But first you need to get a drill bit clamped very close to
perpendicular. I put the bit upside down in the drill chuck, leaving the
shank exposed. Then I raise the table up so that I can tighten a vise on
the bit (using a spacer as needed). With the drill secure in the vise,
loosen the drill chuck and lower the table with the drill bit. THEN put the
bolt in the drill chuck. If the end of the bolt is not close to flat, then
work it over with a file. Then you have some hope of getting the drill
started in the center. Spin up the drill, and carefully feed the bolt down
onto the drill, trying to find the center. My experience is that with some
practice you can get close, and it's hard to get the bit stared too far off
center as it gets thown aside !

One additional benefit of this method is that chips fall down out of the
hole when cutting brass etc.

I'd not wager much that one can get the hole within 20 thou of center every
time, but it should be pretty parallel, and it's a method you can try with
your drill press.

Good luck,

Dave, from Saskatoon where someone forgot to send summer this year, brrrrr

In article , Carlos Valor
says...

looking for recommendation on how to drill a 1" deep 5/16" diameter
hole in the end of a steel 5/8" bolt. it is crucial that the hole be
centered and parallel to the bolt axis.

You've been given a number of different ways to perform this
task. The most difficult part however is still up to you:

You need to decide on a tolerance for your piece. How
accurately does the hole need to be placed in the end,
and how much deviation from the axis is permitted?

The answers to those two questions cannot use any of the
terms:

Dead Nuts On
Absolute
Perfect
etc.

The answer will be something like, I need the hole to be
in the center of the bolt within +/- 0.003 inch, and I need
the other end of the hole to be within 0.001 inch of the
location of the hole's top.

Remember that a) you will have a tough time indicating
to the threads on a faster, so unless there is an unthreaded
portion, you might be doing well with *five* thou accuracy.
And b) often the hex heads on fasteners are poorly aligned
with the shanks. Consider what the function of the hole
is to be, before deciding what is to be aligned *with*.

The easiest, fastest way: a lathe.

If you do it on a drill press, here is one way to come
close: swing the table off to the side, and clamp a thick
aluminum plate so it overhangs under the quill. Carefully
centerdrill a starting hole, and enlarge it to the size
of bolt you you are using.

Without moving the table, fasten the workpiece into the
hole and repeat the process - the hole is roughly aligned
with the quill's axis. The tighter the fit of the bolt
in the hole, the better you will do in terms of accuracy.
For this aproach, +/- 0.010 inch is about the best you
can hope for.

Jim


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please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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DaveK wrote:

Here's a trick that I've used with some success, put the bolt in the drill
chuck ! But first you need to get a drill bit clamped very close to
perpendicular. I put the bit upside down in the drill chuck, leaving the
shank exposed. Then I raise the table up so that I can tighten a vise on
the bit (using a spacer as needed). With the drill secure in the vise,
loosen the drill chuck and lower the table with the drill bit. THEN put the
bolt in the drill chuck.

But Dave, the OP said:

i have a small craftsman drill press, plenty of drill sizes,
and a starret auto punch.

It's rather unlikely that his "small" drill press has a 3/4" chuck, and
that's what's needed to span the head of a standard 1/2" hex bolt.

snipped


I'd not wager much that one can get the hole within 20 thou of center every
time, but it should be pretty parallel, and it's a method you can try with
your drill press.

You're a better and braver man than me Dave. The heads of garden variety
bolts aren't exactly precision machined features. Whenever I've tried to
chuck a hex bolt by its head in a 3-jaw the wobble at the business end
of the bolt was humungous!

SWMBO just asked me to take the kitchen garbage out, so on my way back I
ducked into my basement shop and stuck a couple of brand new 1/2-13 x
1-1/2" bolts in the 3-jaw on my little Stark lathe to check my memories.
TIR at the ends of those bolts was about .08" for one and over .11" on
the other. (I know that my chuck ain't great, but it's not *that* bad.)

But, "pretty is as pretty does" so if it's worked for you Dave then G-d
bless 'ya and I'm not gonna sit here and tell you that it won't. G

Cheers,

Jeff

--
My name is Jeff Wisnia and I approved this message....

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

Thanks everyone for your kind replies. The project is for a
supercharger pulley puller/installer that I am constructing. The
5/8"-18 bolt acts as the forcing screw and the hole is to put a press
fit locating pin (which, in turn, mates with the supercharger shaft).
Trying to stay on the cheap and use basic materials/techniques as
opposed to purchasing a 150+ dollar puller. Thanks again.

"Carlos Valor" wrote in message
om...
Thanks everyone for your kind replies. The project is for a
supercharger pulley puller/installer that I am constructing. The
5/8"-18 bolt acts as the forcing screw and the hole is to put a press
fit locating pin (which, in turn, mates with the supercharger shaft).
Trying to stay on the cheap and use basic materials/techniques as
opposed to purchasing a 150+ dollar puller. Thanks again.

Good luck to you on this. I recently made a camshaft sprocket puller for a
GM DOHC V6 out of an old floor jack cast iron wheel and some latheing and
brazing. The serv. mgr. at the local dealer was good enough to let me take
some pictures of the outrageously expensive GM special tools. And I thought
DaveK's method of centering your hole was just clever as hell. Learn
something new here every day.

Garrett Fulton




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