Hello all,

I am getting close to making some changes to a plate that is essentially
as long a my mill's table, and a little more than twice as wide.
There are three or four sets of hole patterns (e.g. at corners of each
of two fans) that need to align with objects to be attached to the
plate. There are some waste areas (likely to be cut with a hole saw)
that can be placed "using the force" as long as the hole patterns work.

One option would be make jigs for placing the holes using a punch, and
then resort to an electric drill for making the holes. Another option
is to drill a few extra holes for clamping, and then to make covers or
just use hole plugs to repair the damage.

Knowing that I was near limits, I _think_ I managed to orient the items
such that all hole locations can be reached with the plate on the mill.
The plate would need to be turned for that to work. For each item,
the relative spacing of the mounting holes is important for easy
assembly. Two fans need to be mounted within the hole pattern for a
box, but they do not need to be precisely located therein, nor does the
box need to appear on the plate with any particular precision.

The plate is 0.09" or so thick, and at least in the past has been made
of a truly ugly grainy powdery substance that resembles metal until it
is cut Drilling is not a problem.

Would you try to clamp it to the mill, or would you make jigs for the
drilling? If the latter, any suggestions? Would you worry just about
guiding a punch, or would you try to make something to guide the drill
bit itself? I am assuming that any jig would be held in place with
bolts running through holes in waste areas - the fans will make that
easy to do.

Harold, I have not forgotten our open discussion on flycutters, but have
been slammed with computer/electronics work that give the above
mentioned box a reason to exist. I found a good sale on a cheap bench
grinder which stands ready - now I just have to learn how to use it

Thanks!

Bill

In article et,
Bill Schwab wrote:

Would you try to clamp it to the mill, or would you make jigs for the
drilling? If the latter, any suggestions? Would you worry just about
guiding a punch, or would you try to make something to guide the drill
bit itself? I am assuming that any jig would be held in place with
bolts running through holes in waste areas - the fans will make that
easy to do.

For "a few" (I see no indication how many you are making - 1 - 100,
1000, 10,000....), I'd probably just lay out the holes with a scribe and
punch them (did a lot of one-off electronics enclosures in my lab work),
then drill on the punch mark. This is more than adequately precise for
fan mounting (BTDT) with a careful hand and a good drill press. If
you're talking hundreds, jigs are probably in order. If you get to
really high volume, some sort of punch press to stamp them out might be
justified, or (for more flexibility if the parts ever change much) a CNC
mill with a larger table.

The boring old bimetallic hole saw is less likely to bite you than the
fly cutter for making the big fan hole, and again, is more than
adequately precise, and probably faster.

A simple aluminum or phenolic block jig could guide either the punch
(for purists) or the drill (if making only a hundred or so), or could be
upgraded with proper drill bushings for purists and/or higher production
needs. Mild steel also works, just a bit harder to make, depends on the
amount of use it's going to get, and what you have handy for stock.

Mounting it on the mill you have sounds like a pain, and overly precise
for the job at hand (ie, takes much more time fussing than is needed to
do the job adequately, thus, wastes money). Only reason to alter that
thinking is if this is a one-off hobby project and you want to spend
time playing with your mill...

--
Cats, coffee, chocolate...vices to live by

Too much work to do it in the mill. For one plate with multiple sets of
interelated holes, I'd make a simple drill fixture out of 1/4" steel
plate, clamp it down, drill through. If you want to get fancy and do a
dozen plates, use an aluminum block with drill bushings. Search on
"drill bushings" at www.mcmaster.com Drill the pilot hole for the hole
saw as part of the drill fixture. Or even use the hole saw on the
fixture and use the fixture to guide the hole saw.

Bill Schwab wrote:
Hello all,

I am getting close to making some changes to a plate that is essentially
as long a my mill's table, and a little more than twice as wide. There
are three or four sets of hole patterns (e.g. at corners of each of two
fans) that need to align with objects to be attached to the plate.
There are some waste areas (likely to be cut with a hole saw) that can
be placed "using the force" as long as the hole patterns work.

One option would be make jigs for placing the holes using a punch, and
then resort to an electric drill for making the holes. Another option
is to drill a few extra holes for clamping, and then to make covers or
just use hole plugs to repair the damage.

Knowing that I was near limits, I _think_ I managed to orient the items
such that all hole locations can be reached with the plate on the mill.
The plate would need to be turned for that to work. For each item,
the relative spacing of the mounting holes is important for easy
assembly. Two fans need to be mounted within the hole pattern for a
box, but they do not need to be precisely located therein, nor does the
box need to appear on the plate with any particular precision.

The plate is 0.09" or so thick, and at least in the past has been made
of a truly ugly grainy powdery substance that resembles metal until it
is cut Drilling is not a problem.

Would you try to clamp it to the mill, or would you make jigs for the
drilling? If the latter, any suggestions? Would you worry just about
guiding a punch, or would you try to make something to guide the drill
bit itself? I am assuming that any jig would be held in place with
bolts running through holes in waste areas - the fans will make that
easy to do.

Harold, I have not forgotten our open discussion on flycutters, but have
been slammed with computer/electronics work that give the above
mentioned box a reason to exist. I found a good sale on a cheap bench
grinder which stands ready - now I just have to learn how to use it

Thanks!

Bill

For "a few" (I see no indication how many you are making - 1 - 100,
1000, 10,000....), I'd probably just lay out the holes with a scribe and
punch them (did a lot of one-off electronics enclosures in my lab work),
then drill on the punch mark. This is more than adequately precise for
fan mounting (BTDT) with a careful hand and a good drill press. If
you're talking hundreds, jigs are probably in order. If you get to
really high volume, some sort of punch press to stamp them out might be
justified, or (for more flexibility if the parts ever change much) a CNC
mill with a larger table.

This is definitely small volume - one for now, a handful at a time
later. The surface is a little rough for good layout, and I still
cringe over the thought of my previous work on these panels.



Mounting it on the mill you have sounds like a pain, and overly precise
for the job at hand (ie, takes much more time fussing than is needed to
do the job adequately, thus, wastes money).

One caveat: mistakes are needlessly expensive in this case, because the
plates are "medical equipment". Some degree of fussing is appropriate.


Only reason to alter that
thinking is if this is a one-off hobby project and you want to spend
time playing with your mill...

Fair enough, but you should have been around for the first set of these
things =:0 It was enough trouble that I plan on some amount of
overkill. A jig for the punch is probably a nice compromise.

Thanks!

Bill

Roy,

Too much work to do it in the mill. For one plate with multiple sets of
interelated holes, I'd make a simple drill fixture out of 1/4" steel
plate, clamp it down, drill through. If you want to get fancy and do a
dozen plates, use an aluminum block with drill bushings. Search on
"drill bushings" at www.mcmaster.com

For future reference, my understanding is that the bushings require
bored or reamed holes vs. drilled. Is that true?

Given what I have one hand (not much steel), what would you think of an
Al plate intended to guide a punch instead of the drill?



Drill the pilot hole for the hole
saw as part of the drill fixture.

Agreed. I plan to drill oversized holes in the waste area, and then use
them for clamping with a couple of bolts. Sound ok?


Or even use the hole saw on the
fixture and use the fixture to guide the hole saw.

Not to argue with you, but it seems likely that by the time teeth reach
the jig, the pilot hole is already in the wrong place, or am I missing
something? Besides, I want the waste area in place for holding the jig
to the plate. Please speak up if you disagree.

Thanks!!

Bill

In article . net,
Bill Schwab wrote:

This is definitely small volume - one for now, a handful at a time
later. The surface is a little rough for good layout, and I still
cringe over the thought of my previous work on these panels.

Also look into short, stiff drills - all the metalwork suppliers have
them, they are less prone to wandering than longer drills if your rough
surface makes good punch marks a problem, or otherwise messes with good
drilling. And upgrade the light on the drill press (I have no idea what
you have now, but I do know that more light is better as far as really
seeing what you are doing).

--
Cats, coffee, chocolate...vices to live by

Reamed holes are nice for the bushings, it lets you press fit the
bushing, press it out and replace when worn. You would never wear yours
out, just drill, insert bushing with some of the loctite loose bearing
sealant. It will handle a few thousanths slop with no trouble.

Using an aluminum fixture and center punching the holes should work ok,
but you take the chance that drill runout will walk a hole over some
from where you want it. I would make my own center punch by taking an
appropriate pin punch (straight sides) and grinding a center point angle
on the end.

Clamping by using a couple bolts in the waste is fine, should give you a
non slip setup. If you do that, you will have to do the hole saw pilot
hole only. When you get to the hole saw you MUST do it in a drill press.
Since you have predrilled the pilot hole, you should take the drill
center out and replace it with a straight rod (or insert the drill in
backwards) so that you have a round shaft for guidance instead of the
drill flutes.

My first comment was to use the hole saw to drill the 3" (or whatever
size you need) in the fixture, index the hole saw on the large hole in
the fixture, don't use a pilot at all.



Bill Schwab wrote:
Roy,

Too much work to do it in the mill. For one plate with multiple sets
of interelated holes, I'd make a simple drill fixture out of 1/4"
steel plate, clamp it down, drill through. If you want to get fancy
and do a dozen plates, use an aluminum block with drill bushings.
Search on "drill bushings" at www.mcmaster.com


For future reference, my understanding is that the bushings require
bored or reamed holes vs. drilled. Is that true?

Given what I have one hand (not much steel), what would you think of an
Al plate intended to guide a punch instead of the drill?



Drill the pilot hole for the hole

saw as part of the drill fixture.


Agreed. I plan to drill oversized holes in the waste area, and then use
them for clamping with a couple of bolts. Sound ok?


Or even use the hole saw on the fixture and use the fixture to guide
the hole saw.


Not to argue with you, but it seems likely that by the time teeth reach
the jig, the pilot hole is already in the wrong place, or am I missing
something? Besides, I want the waste area in place for holding the jig
to the plate. Please speak up if you disagree.

Thanks!!

Bill

Also look into short, stiff drills - all the metalwork suppliers have
them, they are less prone to wandering than longer drills if your rough
surface makes good punch marks a problem, or otherwise messes with good
drilling.

I have some center bits in a couple of sizes and use them for starting
holes on my mill. Is that what you mean?



And upgrade the light on the drill press (I have no idea what
you have now, but I do know that more light is better as far as really
seeing what you are doing).

Very true. I learned that a couple of months ago; forutnately the
damage was cosmetic, and was limited to a work piece. Still, I need
even more light than what I added as a result of that screw up.

One sincere question: folks are steering me from a mill to a drill
press, which while I have a small drill press, it sends me back to the
mill. What gives?

Bill

Roy,

Reamed holes are nice for the bushings, it lets you press fit the
bushing, press it out and replace when worn. You would never wear yours
out, just drill, insert bushing with some of the loctite loose bearing
sealant. It will handle a few thousanths slop with no trouble.

Great - I'll keep that in mind for other jigs.


Using an aluminum fixture and center punching the holes should work ok,
but you take the chance that drill runout will walk a hole over some
from where you want it. I would make my own center punch by taking an
appropriate pin punch (straight sides) and grinding a center point angle
on the end.

Clamping by using a couple bolts in the waste is fine, should give you a
non slip setup. If you do that, you will have to do the hole saw pilot
hole only. When you get to the hole saw you MUST do it in a drill press.

Fair enough. Why?


Since you have predrilled the pilot hole, you should take the drill
center out and replace it with a straight rod (or insert the drill in
backwards) so that you have a round shaft for guidance instead of the
drill flutes.

There is a set screw that appears to be for that purpose, but my Allen
wrench feels like it's going to give out before the set screw. It's a
little new for pentrating oil, but that might help.


My first comment was to use the hole saw to drill the 3" (or whatever
size you need) in the fixture, index the hole saw on the large hole in
the fixture, don't use a pilot at all.

Got it.

Thanks!

Bill

In article . net,
Bill Schwab wrote:

I have some center bits in a couple of sizes and use them for starting
holes on my mill. Is that what you mean?

Well, center bits make nice starter holes if you want to drill twice. If
you want to drill once, what McMaster calls "short-length drill bits"
which are also called screw machine drill bits are good. You're drilling
0.09" thick material, so 1/2 inch of flute is more than plenty, and more
just makes a bit that will bend more easily.

One sincere question: folks are steering me from a mill to a drill
press, which while I have a small drill press, it sends me back to the
mill. What gives?

The mill you have is difficult to get this thing clamped to and will be
a slow way to do the job. Drill press should be faster. If you prefer to
do the job in the mill, that's your call - we are just offering advice
based on what you've told us about the job, and our own past experience
of what works, and works most effectively. My personal "budget-no-object
neat toys are good" preference in this case would be for a larger CNC
mill, where the plate could be clamped to a piece of wood or plastic
(waste) on the table and the mill would just cut it (fan-holes and all)
while you did something else, but I assume that if your budget was no
object, you'd already have that on a truck heading your way - so I'm
suggesting based on "most cost effective way to make it in the least
time, to adequate tolerance" in the hopes that you can make money on it,
and buy toys to suit you in the future.

With a drill press, you line up the hole, clamp the work to the table
(almost no time at all with a proper drill press lever clamp), drill,
unclamp, line up the next hole. With the mill you're fiddling about with
getting it clamped to the table, which it is too big for, (by the end of
which you're probably done with the drill press), lined up properly,
etc. Then you move to position, drill hole, move to next...

Upgrading the drill press, if needed, will cost a lot less than
upgrading the mill, generally speaking.

--
Cats, coffee, chocolate...vices to live by

Well, center bits make nice starter holes if you want to drill twice. If
you want to drill once, what McMaster calls "short-length drill bits"
which are also called screw machine drill bits are good. You're drilling
0.09" thick material, so 1/2 inch of flute is more than plenty, and more
just makes a bit that will bend more easily.

I will take a look. My existing drill bits are much longer than
necessary for most things I do. Not only will the reduced length reduce
deflection of the bit, it would also simplify my setups.


One sincere question: folks are steering me from a mill to a drill
press, which while I have a small drill press, it sends me back to the
mill. What gives?


The mill you have is difficult to get this thing clamped to and will be
a slow way to do the job. Drill press should be faster. If you prefer to
do the job in the mill, that's your call - we are just offering advice
based on what you've told us about the job, and our own past experience
of what works, and works most effectively.

And it's appecreciated. Your answer is pretty much what I expected. It
makes sense, but I'm not sure that my drill press (which I bought before
realizing a mill was obtainable) is up to it.


My personal "budget-no-object
neat toys are good" preference in this case would be for a larger CNC
mill, where the plate could be clamped to a piece of wood or plastic
(waste) on the table and the mill would just cut it (fan-holes and all)
while you did something else, but I assume that if your budget was no
object, you'd already have that on a truck heading your way

Not to mention the air conditioned detached shop with overhead crane etc.



With a drill press, you line up the hole, clamp the work to the table
(almost no time at all with a proper drill press lever clamp), drill,
unclamp, line up the next hole. With the mill you're fiddling about with
getting it clamped to the table, which it is too big for, (by the end of
which you're probably done with the drill press), lined up properly,
etc. Then you move to position, drill hole, move to next...

Got it.



Upgrading the drill press, if needed, will cost a lot less than
upgrading the mill, generally speaking.

True. However, the drill press is not really worthy of an upgrade, and
the next step up in a mill is not something I'm ready to do. The bottom
line is that the mill gets the drill press work.

All of this has me considering another option. The panel would do well
to have a couple stiffening beams attached to it. I might be able to
arrange for them to turn it into its own subplate. Given a strange
positioning of my vise and some jacks, it might work.

Thanks!

Bill

Ecnerwal was referring to some short stubby standard drills. Usually
about 2/3rds the length of regular drills, fairly short flute length.
The pilot drill in your hole saw is probably an example.

One "problem" with a mill is that it is rigid. You turn the cranks, set
the table where you want it, drill (or mill) the hole. It's very
difficult to use any kind of fixture, (especially with drill bushings!),
because drill bushings depend on the drill moving the part and fixture
into the proper position. You can just mount a flat plate on the mill
table and use it like a fancy drill press. In your case, this would make
sense. A piece of 1/2" aluminum plate would work well.

Bill Schwab wrote:
Also look into short, stiff drills - all the metalwork suppliers have
them, they are less prone to wandering than longer drills if your
rough surface makes good punch marks a problem, or otherwise messes
with good drilling.


I have some center bits in a couple of sizes and use them for starting
holes on my mill. Is that what you mean?



And upgrade the light on the drill press (I have no idea what

you have now, but I do know that more light is better as far as really
seeing what you are doing).


Very true. I learned that a couple of months ago; forutnately the
damage was cosmetic, and was limited to a work piece. Still, I need
even more light than what I added as a result of that screw up.

One sincere question: folks are steering me from a mill to a drill
press, which while I have a small drill press, it sends me back to the
mill. What gives?

Bill

Ok, you don't HAVE to use the drill press for a hole saw, you will WANT
to use a drill press. You want the hole saw to be cutting evenly all the
way around, you do NOT want the pilot hole to get enlarged. Both require
a fairly straight down approach to your drilling operation otherwise the
hole tends to get oversized.

When using a hole saw, direct a blast of compressed air into the cut. It
cools the blade and clears the chips.

Bill Schwab wrote:

Roy,

Reamed holes are nice for the bushings, it lets you press fit the
bushing, press it out and replace when worn. You would never wear
yours out, just drill, insert bushing with some of the loctite loose
bearing sealant. It will handle a few thousanths slop with no trouble.


Great - I'll keep that in mind for other jigs.


Using an aluminum fixture and center punching the holes should work
ok, but you take the chance that drill runout will walk a hole over
some from where you want it. I would make my own center punch by
taking an appropriate pin punch (straight sides) and grinding a center
point angle on the end.

Clamping by using a couple bolts in the waste is fine, should give you
a non slip setup. If you do that, you will have to do the hole saw
pilot hole only. When you get to the hole saw you MUST do it in a
drill press.


Fair enough. Why?


Since you have predrilled the pilot hole, you should take the drill
center out and replace it with a straight rod (or insert the drill in
backwards) so that you have a round shaft for guidance instead of the
drill flutes.


There is a set screw that appears to be for that purpose, but my Allen
wrench feels like it's going to give out before the set screw. It's a
little new for pentrating oil, but that might help.


My first comment was to use the hole saw to drill the 3" (or whatever
size you need) in the fixture, index the hole saw on the large hole in
the fixture, don't use a pilot at all.


Got it.

Thanks!

Bill

Roy,

Ok, you don't HAVE to use the drill press for a hole saw, you will WANT
to use a drill press.

That makes sense. Just checking in case your comment had been safety
related.


You want the hole saw to be cutting evenly all the
way around, you do NOT want the pilot hole to get enlarged. Both require
a fairly straight down approach to your drilling operation otherwise the
hole tends to get oversized.

Thanks for the heads up!

Bill

In article . net,
Bill Schwab wrote:

Ok, you don't HAVE to use the drill press for a hole saw, you will WANT
to use a drill press.

That makes sense. Just checking in case your comment had been safety
related.

Well, don't lock a drill on when using a hole saw. I've been using a 4"
on wood where I have to use a portable drill (vent holes in a building).

You want the drill to stop if the hole-saw binds and rips the drill out
of your hands. ;-)

--
Cats, coffee, chocolate...vices to live by

Yep!!! My el cheapo import drill press has a built in torque sensing
clutch for such situations. Works nicely to control the effort to rip
things and send them flying. I suppose if I got the proper belts they
would stop slipping and it would work better but why bother?

Ecnerwal wrote:
In article . net,
Bill Schwab wrote:


Ok, you don't HAVE to use the drill press for a hole saw, you will WANT
to use a drill press.

That makes sense. Just checking in case your comment had been safety
related.


Well, don't lock a drill on when using a hole saw. I've been using a 4"
on wood where I have to use a portable drill (vent holes in a building).

You want the drill to stop if the hole-saw binds and rips the drill out
of your hands. ;-)

According to Ecnerwal :
In article . net,
Bill Schwab wrote:

This is definitely small volume - one for now, a handful at a time
later. The surface is a little rough for good layout, and I still
cringe over the thought of my previous work on these panels.

Also look into short, stiff drills - all the metalwork suppliers have
them, they are less prone to wandering than longer drills if your rough
surface makes good punch marks a problem, or otherwise messes with good
drilling.

They are usually listed under "Screw Machine Length drills".

While you are at it -- look for split point ones -- which do a
better job of cutting without wandering. Or perhaps (for mild aluminum)
the drill bits which are made for wood -- a sharp center spur to feel
for the center punch mark, flat tips, with ears at the OD, to cut
through the edge before drilling through the bulk, resulting in cleaner
holes with less burrs.

And upgrade the light on the drill press (I have no idea what
you have now, but I do know that more light is better as far as really
seeing what you are doing).

Amen!

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Hello all,

The clamping might turn out to be easier than I first thought. I am
packaging a computer (PC/104+) and need to make sure that everything
fits, the fans aren't blocked, the air flow makes sense, the cables all
reach their respective components, etc.

Cable lengths were becoming a problem, and suggested a design change
that might be very helpful. One fan could end up near the top, the
other near a side of the panel. If that sticks, then I can easily clamp
to cut the top/center fan hole (plenty of room to the sides), and then
use that hole for clamping for the side fan. This puts the computer box
off-center where I wanted all along - I think =:0

There are holes for attaching the box to the panel that will be
unreachable on the mill, but, there is a ready-made jig for them. If I
hit a couple of holes near the edges, I can use them to bolt one of two
box covers to the panel to guide a punch.

Funny how machine designs always looks obvious once they are finished.

Bill