I will be drilling some plates with holes around 13/16 that have to match
up.
The bolt hole pattern is for eight holes on three different plates that have
to
match. From what I understand there will be 26 sets of three. One set if
the three will be done by a machine shop and the rest are my responsibility.
I am thinking of an accurate scribed layout, pilot drilling and drilling
one plate to use as a master before stack drilling. The plates are around
3/4 thick. Any suggestions on how to make locations more accurate??? I am
limited to a radial arm drill press. No milling machine. Edge distance are
not critical but hole pattern is.
Randy

I will be drilling some plates with holes around 13/16 that have to match
up.
The bolt hole pattern is for eight holes on three different plates that
have to
match.

How much time / money do you have to spend on this? I'd suggest asking the
machine shop to make your holes undersized in the "template" and pressing in
drill bushings for a pilot drill operation. Then follow through the pilot
holes to make the larger finished holes.

How many parts total do you have to make? i.e. is this batch the entire job
or are you eventually looking at hundreds, thousands, etc.
--


Regards,
Joe Agro, Jr.
http://www.autodrill.com
http://www.multi-spindle-heads.com

V8013

There are 26 sets of three from what I understand... We have a bid price to
keep under on this job. I am pretty sure the holes will be 1/16 oversize
for structural connections.
The idea of me drilling these is to save time on delivery plus cost.
What concerns me is the three plates. Two plates with matching holes is
not difficult. From past experience it seems to be a geometric increase in
possible misalignments.

"Joe" wrote in message
...
I will be drilling some plates with holes around 13/16 that have to match
up.
The bolt hole pattern is for eight holes on three different plates that
have to
match.

How much time / money do you have to spend on this? I'd suggest asking
the machine shop to make your holes undersized in the "template" and
pressing in drill bushings for a pilot drill operation. Then follow
through the pilot holes to make the larger finished holes.

How many parts total do you have to make? i.e. is this batch the entire
job or are you eventually looking at hundreds, thousands, etc.
--


Regards,
Joe Agro, Jr.
http://www.autodrill.com
http://www.multi-spindle-heads.com

V8013

"Randy Zimmerman" wrote in message
news:E7Azd.594424$%k.181706@pd7tw2no...
I will be drilling some plates with holes around 13/16 that have to match
up.
The bolt hole pattern is for eight holes on three different plates that
have to
match. From what I understand there will be 26 sets of three. One set if
the three will be done by a machine shop and the rest are my
responsibility.
I am thinking of an accurate scribed layout, pilot drilling and
drilling
one plate to use as a master before stack drilling. The plates are around
3/4 thick. Any suggestions on how to make locations more accurate??? I
am limited to a radial arm drill press. No milling machine. Edge
distance are not critical but hole pattern is.
Randy




Can the machine shop spot or center drill the top plates of each set? You
could chuck up a 60 deg pointed rod to locate each hole. Can someone tack
weld the plates together to prevent movement?
Randy

Good point about a rod. I just might machine up a centering rod before
spotting my large drill bit on the radial arm.
I always tack three or more bars across the sides of the plates. I hate
people who tack directly. Listening to me rant about their ignorance while
trying to break plates apart is not pleasant.
My guess is that I will not see the plates drilled in the machine shop
until long after I have drilled my plates.
Randy

"Randy Replogle" wrote in message
news:usAzd.6810$1U6.2364@trnddc09...

"Randy Zimmerman" wrote in message
news:E7Azd.594424$%k.181706@pd7tw2no...
I will be drilling some plates with holes around 13/16 that have to match
up.
The bolt hole pattern is for eight holes on three different plates that
have to
match. From what I understand there will be 26 sets of three. One set
if
the three will be done by a machine shop and the rest are my
responsibility.
I am thinking of an accurate scribed layout, pilot drilling and
drilling
one plate to use as a master before stack drilling. The plates are
around
3/4 thick. Any suggestions on how to make locations more accurate??? I
am limited to a radial arm drill press. No milling machine. Edge
distance are not critical but hole pattern is.
Randy




Can the machine shop spot or center drill the top plates of each set? You
could chuck up a 60 deg pointed rod to locate each hole. Can someone tack
weld the plates together to prevent movement?
Randy

It sounds to me like what you need to do is get or make your self a transfer
punch. This is a center punch that fits snugly in the hole you are trying
to match and allows you to mark the center on the second plate.

Have the machine shop turn some 13/16 plugs with a hole in the center that
will match the diameter of a transfer punch.

Set the master plate over the other plate insert one of the plugs and center
punch the hole location. Drill that hole to size and then reassemble with
the master plate. Align the hole you drilled with the hole you marked it
from and insert a plug through both the master and the copy. Mark your
second hole and drill, reassemble and continue till all the plates are done.
Doing one at a time will be slower than marking them all at once, but it
should get you dead on that way.

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.
"Randy Zimmerman" wrote in message
news:E7Azd.594424$%k.181706@pd7tw2no...
I will be drilling some plates with holes around 13/16 that have to match
up.
The bolt hole pattern is for eight holes on three different plates that
have
to
match. From what I understand there will be 26 sets of three. One set if
the three will be done by a machine shop and the rest are my
responsibility.
I am thinking of an accurate scribed layout, pilot drilling and
drilling
one plate to use as a master before stack drilling. The plates are around
3/4 thick. Any suggestions on how to make locations more accurate??? I
am
limited to a radial arm drill press. No milling machine. Edge distance
are
not critical but hole pattern is.
Randy

"Randy Zimmerman" wrote in message
news:E7Azd.594424$%k.181706@pd7tw2no...
I will be drilling some plates with holes around 13/16 that have to match
up.

We'll assume that each set of three only has to match itself (this is *very*
important.)

I would take one plate that the machine shop has done and use it as a master
template. Make or buy a transfer punch of the appropriate size. Clamp and
punch 26 blanks using the master and the transfer punch.

Now, simply clamp (I also like the idea of welding them) two unpunched
blanks to each punched blank and drill together.

From my experience, the fixturing on the radial arm is going to make or
break your profit margin. You need to be able to clamp/unclamp your part,
and index it to the next location, very quickly. I wouldn't reposition the
head on the press unless the plates' size prevents them from being moved
between holes.

Also, make sure you don't have to spend a lot of time clearing chips/coolant
as this will make the job much longer. Using posts or blocks to raise the
part off the table will help this issue (perhaps 2"+). Make sure there is
lots of support around the hole being drilled as you don't want anything to
move.

I would also suggest splitting the point on the drill and popping the hole
in one shot. You should be able to get a straight hole although you may be
inclined to peck the drill as this will help the location.

HTH.

Regards,

Robin

I am getting some good ideas. We have used our punching dies from the
ironworker for larger transfer punches in some cases.
In most of my situations the pieces I drill are heavy being over 100
pounds. Recently I was doing stacked drilled 3.75 thick plate. It took as
much time to load and align as to drill the nine holes. We used a quarter
inch plate masterpunched and transferred with punch dies.
On this coming job I will try the transfer punch idea. I have not had
much luck using a split point on large bits and starting on the centerpop.
I have been using centerdrill first then changing bits when the arm is
locked.
Randy

"Robin S." wrote in message
. ..

"Randy Zimmerman" wrote in message
news:E7Azd.594424$%k.181706@pd7tw2no...
I will be drilling some plates with holes around 13/16 that have to match
up.

We'll assume that each set of three only has to match itself (this is
*very* important.)

I would take one plate that the machine shop has done and use it as a
master template. Make or buy a transfer punch of the appropriate size.
Clamp and punch 26 blanks using the master and the transfer punch.

Now, simply clamp (I also like the idea of welding them) two unpunched
blanks to each punched blank and drill together.

From my experience, the fixturing on the radial arm is going to make or
break your profit margin. You need to be able to clamp/unclamp your part,
and index it to the next location, very quickly. I wouldn't reposition the
head on the press unless the plates' size prevents them from being moved
between holes.

Also, make sure you don't have to spend a lot of time clearing
chips/coolant as this will make the job much longer. Using posts or blocks
to raise the part off the table will help this issue (perhaps 2"+). Make
sure there is lots of support around the hole being drilled as you don't
want anything to move.

I would also suggest splitting the point on the drill and popping the hole
in one shot. You should be able to get a straight hole although you may be
inclined to peck the drill as this will help the location.

HTH.

Regards,

Robin

"Randy Zimmerman" wrote in message
news:eS_zd.577833$Pl.276235@pd7tw1no...
I am getting some good ideas. We have used our punching dies from the
ironworker for larger transfer punches in some cases.
In most of my situations the pieces I drill are heavy being over 100
pounds. Recently I was doing stacked drilled 3.75 thick plate. It took
as much time to load and align as to drill the nine holes. We used a
quarter inch plate masterpunched and transferred with punch dies.
On this coming job I will try the transfer punch idea. I have not had
much luck using a split point on large bits and starting on the centerpop.
I have been using centerdrill first then changing bits when the arm is
locked.

There's no doubt it is ideal to c-drill, pilot and then drill to full
diameter (or even double drill), but that takes time. In your situation, it
would take a lot of time. This is why it is critical to know if the sets
must match only themselves, or all the other plates as well.

When drilling large-ish holes in steel with a hand drill, you really start
to understand why they sell split-point drills. Correctly ground, these
significantly reduce the power required to drill a hole. Naturally, if they
are incorrectly ground, you're going to lose your edge prematurely, or the
drill will wander, or, or, or...

This is the kind of job where a well thought out work plan and efficient
fixturing will save lots of time.

Good luck, and of course let us know how you make out.

Regards,

Robin

Have the machine shop drill just the first three holes with a 1/8" bit, then
make a 1/8" punch to fit the drilled holes to mark the centers for all of them,
then drill all using the marked centers. May be cheaper that having the shop
make your transfere punches

When I need a large or odd sized transfer punch, I use an accurate 1/4"
punch I made and hardened guided by a brass or aluminum bushing. I
face, drill and ream a piece of brass or aluminum then turn the outside
to the required diameter. This has a number of advantages including the
flat face that holds the guide square to the surface being punched.

Ted