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  #1   Report Post  
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

Greetings,

Having a need to drill some stainless steel, I am looking for a small
drill
press. I have done some research and gather that bigger/more
sturdy/heavier
is better, but it costs more... so I'm concentrating on 12" bench-top
models,
and the arbitrary price limit is $200, although I would consider
raising it
if all that can be found under it is useless for drilling stainless
(up to
1" holes). Even in this reduced set, there are quite a few choices.
I have read the FAQ but it doesn't go into details of drill presses.

Before going on to specific brands and models, a general overview of
my
understanding of what I've learned over the last couple of days:
somebody
set me straight if I'm wrong!

o More power is better. Some drill presses under $200 have 2/3 HP
motors,
others have much less.
o More speeds is better. Particularly for large holes in tough
materials,
low speeds are important. Many less expensive units have 5 speeds, a
few
have 12 or 16 (1 versus 2 belts). None that I could find in that
price
range had variable speed. Some have a low speed of 540, others 280,
620,
500, etc... How important is it to concentrate on the lowest
possible
speeds for large holes in stainless steel?
o The downstroke is usually between 2.x to 3.x inches, is this
sufficient
for serious work? I presume that longer is better as long as the
machine
is built right and the drill bit does not wobble. Of course the
runout
number is something that I haven't seen in any description.
o Chuck capacity: bigger is better. The 1" bit I already have
requires 3/8
so I would say 1/2" is minimum (and common), 5/8 is better.
o Build quality and sturdiness: closer tolerances and better materials
are
of course better, but this is one that's hard to judge without
having
tried the different models. Fire away at the different models
below!
I presume the "heavy duty" models are better.
o Table size: bigger is better (?) table adjustments are nice, but the
more
adjustments the more the table can move when it's not supposed to if
not
built sturdily.
o Ease of moving belts: this is one that no manufacturer will tell you
about.
I have to depend on people's experiences, and I've already read that
some
are quite difficult to change. Fire away!

Other things I should consider?

I have gone by Sears and Home Depot, so the first two I have seen in
person.

Home Depot only had a couple of Ryobi (10" and 12": DP120) that seemed
quite
flimsy. The specs for the DP120 can be found he

http://www.ryobitools.com/product/pr...at=4&toolcat=7

I have also read an account of a Home Depot drill press falling
apart on first use. One good thing about this model is that it has 12
speeds
and a low speed of 280 RPMs. Opinions on this model?

The Sears one (Mfr number 21912, Sears #00921912000) seemed well made
and
looked suspiciously like some Central Machinery models available at
www.harborfreight.com. Can anyone confirm that Central Machinery
makes the
Craftsman drill presses? It can be found he

http://www.sears.com/sr/javasr/produ...=00 921912000

Pluses: 2/3 hp motor and it seems well made. Minuses: only 5 speeds
and
lowest is 540 RPMs.

Other brands/models I found on the web:

Northern Industrial Tools BP-024: What they show here

http://www.northerntool.com/webapp/w... goryId=93622

looks good, but they don't tell you much. 16 speeds but no mention of
what
the speeds are. The shipping puts it at $220. It's heavier than
many.

At amazon.com 3 candidate models can be found he

http://www.amazon.com/exec/obidos/tg...320170-4640925

The Delta DP300 and DP350 are a little below and above the $200 mark,
but I
have read bad things about the quality of the Delta equipment. The
Fisch
Precision Tools DP2000 has one glowing review and fits the price limit
as
the shipping is included. The motor is kind of small (1/3hp) and the
lowest
speed is 500 (6 speeds). Does anyone have opinions on this model and
the
Deltas?

The Central Machinery 38142-6VGA available here

http://www.harborfreight.com/cpi/cta...emnumber=38142

looks really good: big motor, 16 speeds (240-3600: the biggest range I
found), chuck capacity to 5/8, "heavy duty", etc... Opinions?

At the moment, I'm leaning towards this one. Are there any show
stoppers here?
Anyone with direct experience?

Anyway, this is already getting too long without getting into more
brands/models. Does anyone have other recommendations?

I would also be grateful for pointers to lowest cost vendors. I have
checked
amazon/tooldigger, northerntool and harborfreight.

I would also be grateful for pointers to lowest cost vendors. I have
checked
amazon/tooldigger, northerntool and harborfreight.

Let the discussion begin!

Thanks.

A.
  #2   Report Post  
Grant Erwin
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

Check out http://www.tinyisland.com/htbdrillp.txt - GWE

wrote:
Greetings,

Having a need to drill some stainless steel, I am looking for a small
drill
press. I have done some research and gather that bigger/more
sturdy/heavier
is better, but it costs more... so I'm concentrating on 12" bench-top
models,
and the arbitrary price limit is $200, although I would consider
raising it
if all that can be found under it is useless for drilling stainless
(up to
1" holes). Even in this reduced set, there are quite a few choices.
I have read the FAQ but it doesn't go into details of drill presses.

Before going on to specific brands and models, a general overview of
my
understanding of what I've learned over the last couple of days:
somebody
set me straight if I'm wrong!

o More power is better. Some drill presses under $200 have 2/3 HP
motors,
others have much less.
o More speeds is better. Particularly for large holes in tough
materials,
low speeds are important. Many less expensive units have 5 speeds, a
few
have 12 or 16 (1 versus 2 belts). None that I could find in that
price
range had variable speed. Some have a low speed of 540, others 280,
620,
500, etc... How important is it to concentrate on the lowest
possible
speeds for large holes in stainless steel?
o The downstroke is usually between 2.x to 3.x inches, is this
sufficient
for serious work? I presume that longer is better as long as the
machine
is built right and the drill bit does not wobble. Of course the
runout
number is something that I haven't seen in any description.
o Chuck capacity: bigger is better. The 1" bit I already have
requires 3/8
so I would say 1/2" is minimum (and common), 5/8 is better.
o Build quality and sturdiness: closer tolerances and better materials
are
of course better, but this is one that's hard to judge without
having
tried the different models. Fire away at the different models
below!
I presume the "heavy duty" models are better.
o Table size: bigger is better (?) table adjustments are nice, but the
more
adjustments the more the table can move when it's not supposed to if
not
built sturdily.
o Ease of moving belts: this is one that no manufacturer will tell you
about.
I have to depend on people's experiences, and I've already read that
some
are quite difficult to change. Fire away!

Other things I should consider?

I have gone by Sears and Home Depot, so the first two I have seen in
person.

Home Depot only had a couple of Ryobi (10" and 12": DP120) that seemed
quite
flimsy. The specs for the DP120 can be found he

http://www.ryobitools.com/product/pr...at=4&toolcat=7

I have also read an account of a Home Depot drill press falling
apart on first use. One good thing about this model is that it has 12
speeds
and a low speed of 280 RPMs. Opinions on this model?

The Sears one (Mfr number 21912, Sears #00921912000) seemed well made
and
looked suspiciously like some Central Machinery models available at
www.harborfreight.com. Can anyone confirm that Central Machinery
makes the
Craftsman drill presses? It can be found he

http://www.sears.com/sr/javasr/produ...=00 921912000

Pluses: 2/3 hp motor and it seems well made. Minuses: only 5 speeds
and
lowest is 540 RPMs.

Other brands/models I found on the web:

Northern Industrial Tools BP-024: What they show here

http://www.northerntool.com/webapp/w... goryId=93622

looks good, but they don't tell you much. 16 speeds but no mention of
what
the speeds are. The shipping puts it at $220. It's heavier than
many.

At amazon.com 3 candidate models can be found he

http://www.amazon.com/exec/obidos/tg...320170-4640925

The Delta DP300 and DP350 are a little below and above the $200 mark,
but I
have read bad things about the quality of the Delta equipment. The
Fisch
Precision Tools DP2000 has one glowing review and fits the price limit
as
the shipping is included. The motor is kind of small (1/3hp) and the
lowest
speed is 500 (6 speeds). Does anyone have opinions on this model and
the
Deltas?

The Central Machinery 38142-6VGA available here

http://www.harborfreight.com/cpi/cta...emnumber=38142

looks really good: big motor, 16 speeds (240-3600: the biggest range I
found), chuck capacity to 5/8, "heavy duty", etc... Opinions?

At the moment, I'm leaning towards this one. Are there any show
stoppers here?
Anyone with direct experience?

Anyway, this is already getting too long without getting into more
brands/models. Does anyone have other recommendations?

I would also be grateful for pointers to lowest cost vendors. I have
checked
amazon/tooldigger, northerntool and harborfreight.

I would also be grateful for pointers to lowest cost vendors. I have
checked
amazon/tooldigger, northerntool and harborfreight.

Let the discussion begin!

Thanks.

A.


  #3   Report Post  
DoN. Nichols
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

In article ,
wrote:
Greetings,

Having a need to drill some stainless steel, I am looking for a small
drill
press. I have done some research and gather that bigger/more
sturdy/heavier
is better, but it costs more... so I'm concentrating on 12" bench-top
models,


Note that the 12" models can drill holes centered only 6" from
the nearest edge of the workpiece. If this is sufficient, fine.
Otherwise, consider larger, even if you are over your price limit.

and the arbitrary price limit is $200, although I would consider
raising it
if all that can be found under it is useless for drilling stainless
(up to
1" holes).


You don't state which stainless steel you intend to drill, but
let's assume that it is the one of nasty reputation, 304. Looking in my
copy of _Machinery's Handbook_, I find, for 304 SS, and uncoated HSS
drills, the SFM (Surface Feet per Minute) for really pushing the drill
is 75 to 65 SFM. Carbides are 520 SFM for hard, and 310 for tough, and
coated carbides (tough) are 625 SFM.

Note that carbide drills in that size are *very* expensive, so
we'll calculate based on HSS. And I don't think that there are any
Silver & Demming (e.g. reduced shank) drills, in solid carbide, so HSS
is the most likely one for you.

Now -- for the fastest for HSS was 75 SFM. So -- the RPM for
that maximum SFM with a 1" drill bit is about 286 RPM. And this is
pushing a drill at a speed which will wear it out a bit faster, but
will produce more parts (these speeds are for industrial production, not
hobby work). So -- this will limit your choices

Even slower speeds would be nice.

[ ... ]

o More power is better. Some drill presses under $200 have 2/3 HP
motors,


And some vendors lie more about their motor horsepower than
others do. Some are running the motor so close to the edge that they
*will* burn up in your tasks.

Note that with some stainless steel variants, if you can't push
the drill hard enough, it will work-harden the stainless steel, and the
subsequent drill bits won't be able to re-start the cutting.

You can get away with smaller motors with more speed reduction,
and this may be what you will need to do for your work.

others have much less.
o More speeds is better. Particularly for large holes in tough
materials,
low speeds are important.


*Very* important for what you are trying to do.

Many less expensive units have 5 speeds, a
few
have 12 or 16 (1 versus 2 belts). None that I could find in that
price
range had variable speed. Some have a low speed of 540, others 280,
620,
500, etc... How important is it to concentrate on the lowest
possible
speeds for large holes in stainless steel?


How many drill bits do you want to use per hole? Even the 280
RPM one is pushing things a bit for hobby work.

o The downstroke is usually between 2.x to 3.x inches, is this
sufficient
for serious work?


How thick is your stainless steel? You will want a minimum
stroke of probably at least a half inch longer than your workpiece
thickness with a 1" drill. You may need more if you have to lift the
workpiece out of fixturing, or if you need to change the drill bit
without disturbing the workpiece.

I presume that longer is better as long as the
machine
is built right and the drill bit does not wobble. Of course the
runout
number is something that I haven't seen in any description.


You won't. Most of the machines you have found are various
flavors of imports, and are variable depending on the phase of the moon
when they were constructed.

o Chuck capacity: bigger is better. The 1" bit I already have
requires 3/8
so I would say 1/2" is minimum (and common), 5/8 is better.


I think that a 1" Silver & Demming bit (reduced shank) will
probably put too much stress on a smaller chuck and shank.

Ideally, for this size, I would suggest getting drill bits with
a Morse taper shank to fit the drill press spindle directly, without a
chuck being involved at all. Stainless steel is *tough* stuff, and you
are proposing large holes. And most of the drill presses within your
budget will have only MT-2 shanks, while a 1" drill is happer with a
MT-3 shank.

[ ... ]

The Delta DP300 and DP350 are a little below and above the $200 mark,
but I
have read bad things about the quality of the Delta equipment. The
Fisch
Precision Tools DP2000 has one glowing review and fits the price limit
as
the shipping is included. The motor is kind of small (1/3hp) and the
lowest
speed is 500 (6 speeds). Does anyone have opinions on this model and
the
Deltas?


*Old* Deltas (made in the USA) could be very good machines.
What you get today (new) is yet more imports, and probably tailored for
woodwork, not steel.

The Central Machinery 38142-6VGA available here

http://www.harborfreight.com/cpi/cta...emnumber=38142

looks really good: big motor, 16 speeds (240-3600: the biggest range I
found), chuck capacity to 5/8, "heavy duty", etc... Opinions?


The speed is a benefit. Plan to replace the belts fairly soon,
as they tend to have rather marginal belts, and you will be loading it
seriously.

The spindle is only a MT-2. I know, as I have a floor-standing
version of this which is now perhaps 19 years old. I don't use the
original chuck. I no longer have the original belts, and I don't push
it anywhere near as hard as what you plan. The belts are not really
wide enough to transmit the torque which you will need to do this work.
(But neither are they on most of what you are looking at, and I don't
have time to visit *all* of your URLs.

At the moment, I'm leaning towards this one. Are there any show
stoppers here?


One potential one that I see. This -- like mine -- has a round
table which is clamped by a hollow shank which is perhaps 1-1/2"
diameter. When drilling anything, you want it either clamped down to
the table, or clamped in such a way that the column will keep it from
spinning. If you are clamped down to the table, the center clamp on
that rotating table may not be sufficient to keep it from spinning,
which could make things rather exciting.

Anyone with direct experience?


I forget who they called themselves when I got mine, but the
fact that I haven't broken down and gotten a serious US made one so far
says that overall this one is pretty satisfactory. The belts *will*
slip under hard drilling, and the belt tensioning device is marginal at
best.

Anyway, this is already getting too long without getting into more
brands/models. Does anyone have other recommendations?


Yes -- find a used machine tool dealer, and look for a serious
drill press -- with at least a MT-3 spindle. Plan to drive the drills
directly -- no chuck involved.

Expect that such a drill press will also probably need three
phase, so plan on building a rotary converter -- or hooking up VFD,
which will allow you to get even more speed control, as you can control
the motor speed directly, to supplement the belt reduction.

I would also be grateful for pointers to lowest cost vendors. I have
checked
amazon/tooldigger, northerntool and harborfreight.


I don't think that you can do your proposed task with anything
*new* near your price range -- but a good used piece of equipment might
be available from the used dealers.

Give us a clue where you are located, and perhaps we can point
you to a used equipment dealer known to do things right in your
vicinity.

Good Luck,
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 ---
  #4   Report Post  
john johnson
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

All good advice so far, just another thing to watch is rigidity, something I
got got caught with. Put a block of wood between the chuck or spindle and
the table, then put some downward pressure on the handle, and have a look at
the how the table and head flex away from each other.

My cheap import would not drill a decent hole in anything, the hole bored in
the head casting was far too large for the column, so it rocked on the
column. After I fixed that I found the table flexing away from its mounting.
The boss cast into the mounting which allows the table to swivel side to
side was cast off center, and it had cracked through where the clamping bolt
screwed into it.

If you are drilling stainless, the thing that will wear out your drill is
work hardening of the stainless if you don't keep enough pressure on the
drill, so rigidity is even more important. Most of the older drills are
built like battleships.

regards,

John


  #5   Report Post  
AndrewV
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.


----- Original Message -----
From:
Newsgroups: rec.crafts.metalworking
Sent: Thursday, May 13, 2004 9:00 PM
Subject: Bench-top drill press recommendation? and what I found so far.


Greetings,

Having a need to drill some stainless steel, I am looking for a small
drill
press. I have done some research and gather that bigger/more
sturdy/heavier
is better, but it costs more... so I'm concentrating on 12" bench-top
models,
and the arbitrary price limit is $200, although I would consider
raising it
if all that can be found under it is useless for drilling stainless
(up to
1" holes). Snip


I have a 12" Ryobi that worked well for smaller (less then 1/2") holes in
thinner material IE: quick & dirty. It met its demise when I attempted to
drill an 11/16 " hole in 3/8"s mild steel and the casting that holds the
table to the column fractured. It was real exciting for a moment while I
watched the table and my workpiece spin and wobble. Any way I replaced it
with a mid 1950's Delta 17" floor model. I got it at an industrial surplus
place for $250, it came with an 8"quick vise and a box of assorted drill
bits(3/4 and up). It is built like a tank and most of its parts are still
available from Delta. The motor was replaced sometime ago and is a bit
undersized @ 1/2 hp but it does the job. I have a 2hp 3 phase motor that
will fit and as soon as I scrounge the right VFD I'll switch things over and
have a very capable variable speed drill press for far less then the cost of
a new one.

If I was going to drill a lot of large holes in thicker stainless (or
anything for that matter) I would look at getting a set of rotobroches and
whatever adapters I needed to mount them in my drillpress. They would likely
do a better job and require less of the drillpress then the equivalent size
drill bit.

My 2 cents hope it helps.

Enjoy the hunt

Andrew V




  #6   Report Post  
Stan Schaefer
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

wrote in message . com...


A 1" hole in stainless steel calls for something a little heavier than
just a small drill press if you want to use twist drills. How thick,
though? If it's in sheet metal and the hole has relatively loose
tolerances, a chassis punch might be in order. A decent hole saw
would do the job, too, on a small machine. You do have to watch the
slow speeds when buying a drill press, the fancier and more expensive
models have another jackshaft and pulley in the power train for more
speed choices and/or lower speeds.

If you're drilling through holes in thick bars, you're going to want a
rigid setup which translates to a heavy spindle, a big column and
substantial castings. Also a lot more weight.

I would not be looking at Sears' or Home Depot's offerings. Delta has
some decent drill presses in their light industrial line, but the home
workshop line is the same stuff that all the other importers sell.
Depending on where you are, you may be able to find used domestically
manufactured equipment for cheaper than import, this is very regional,
though. HF may have something that would do what you want, I wouldn't
order it mailorder though. A trip to one of the retail stores to look
over the item before you buy it is in order. You definitely want to
look over the stuff before you get out of the parking lot with it and
replace the belts with Gates or Goodyear ones at the first
opportunity.

If you just have to go import and mailorder, take a look at Enco's
offerings. On some of the machine tools, you used to be able to get a
U.L. listed motor as an option, to me, it'd be worth it.

Stan
  #7   Report Post  
John Manders
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

You have had some good replies here. I would second the Roto broach route.
The power to drill a hole is proportional to the volume of swarf produced.
Roto broaches win there. If you Must use a drill bit, don't use a reduced
shank one. The leverage means that the chuck has to grip the smaller
diameter tighter to avoid slip. A taper shank is better. Go for a bigger
taper wherever possible.
Have you considered a budget mill? I have one and it is far more rigid than
my drill.
Definitely allow for clamping the workpiece down well. Having your work
chase you around the shop looks funny on Tom and Jerry. It's not so good in
real life.
Remember to allow somewhere for the drill to break out into. Some drills
have a hole in the centre of the table but it is not likely to be 1".
Keep your drills sharp. This is especially important with stainless. It work
hardens real well and then you have a big problem.
If you can get a used industrial drill, they are generally better even
though the spec is the same. I had to drill a number of 1" holes in some
3/4" steel recently. My cheap drill took 5 minutes per hole. The Meddings we
had at work did it in 2 minutes per hole. The motor power was the same on
each, 3/4 HP. The Meddings was 3 phase though.
Good luck

John

"AndrewV" wrote in message
...

----- Original Message -----
From:
Newsgroups: rec.crafts.metalworking
Sent: Thursday, May 13, 2004 9:00 PM
Subject: Bench-top drill press recommendation? and what I found so far.


Greetings,

Having a need to drill some stainless steel, I am looking for a small
drill
press. I have done some research and gather that bigger/more
sturdy/heavier
is better, but it costs more... so I'm concentrating on 12" bench-top
models,
and the arbitrary price limit is $200, although I would consider
raising it
if all that can be found under it is useless for drilling stainless
(up to
1" holes). Snip


I have a 12" Ryobi that worked well for smaller (less then 1/2") holes in
thinner material IE: quick & dirty. It met its demise when I attempted to
drill an 11/16 " hole in 3/8"s mild steel and the casting that holds the
table to the column fractured. It was real exciting for a moment while I
watched the table and my workpiece spin and wobble. Any way I replaced it
with a mid 1950's Delta 17" floor model. I got it at an industrial surplus
place for $250, it came with an 8"quick vise and a box of assorted drill
bits(3/4 and up). It is built like a tank and most of its parts are still
available from Delta. The motor was replaced sometime ago and is a bit
undersized @ 1/2 hp but it does the job. I have a 2hp 3 phase motor that
will fit and as soon as I scrounge the right VFD I'll switch things over

and
have a very capable variable speed drill press for far less then the cost

of
a new one.

If I was going to drill a lot of large holes in thicker stainless (or
anything for that matter) I would look at getting a set of rotobroches and
whatever adapters I needed to mount them in my drillpress. They would

likely
do a better job and require less of the drillpress then the equivalent

size
drill bit.

My 2 cents hope it helps.

Enjoy the hunt

Andrew V




  #9   Report Post  
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

Hello again,

I'm impressed by the knowledge here! And by the detailed information
given. Many thanks to everybody that has contributed to this
discussion. I'm following up the article by Don Nichols because of
the variety of points he raises, but all the other responses have
been very valuable. Thank you all! I had already read the article
from 1998 pointed to by another poster about what to watch for when
buying used. I didn't think I was going to do this, but in light
of what has transpired here, I'm now going to check out used drill
presses.

Note that the 12" models can drill holes centered only 6" from
the nearest edge of the workpiece. If this is sufficient, fine.
Otherwise, consider larger, even if you are over your price limit.


The pieces I need to drill now are 1/16" thick (the 1" hole), and 1/8"
thick (smaller holes) and at most 1/2" from an edge, so size is not
an issue.


... (lots of valuable info deleted )
Note that carbide drills in that size are *very* expensive, so
we'll calculate based on HSS. And I don't think that there are any
Silver & Demming (e.g. reduced shank) drills, in solid carbide, so HSS
is the most likely one for you.


I bought a set of 2 tapered bits, the first one to 1/2" and the second
from 1/2" to 1". These are to drill into 1/16" thick 316 stainless.
They are probably HSS (I don't have them nearby to check at the
moment, they cost $30).
The 1/8" 316 stainless will be drilled with smaller cobalt bits.

... (more good info deleted)
How many drill bits do you want to use per hole? Even the 280
RPM one is pushing things a bit for hobby work.


For the 1" holes, the two tapered bits I bought have something like 10
different sizes each, progressively larger. This, I presume, has the
same effect as using 20 progressively bigger drill bits.

How thick is your stainless steel? You will want a minimum
stroke of probably at least a half inch longer than your workpiece
thickness with a 1" drill. You may need more if you have to lift the
workpiece out of fixturing, or if you need to change the drill bit
without disturbing the workpiece.


This is important, as the 1" holes are to go on opposing faces of 2"
square tube, so if I wanted to drill two holes without unclamping the
piece the stroke should be 2" plus the length of the tapered drill
bit. More than the small drill presses I was considering can do.
The alternative is to unclamp the piece and reverse it, but this
gets into issues of alignment and rigidity, as someone else pointed
out.

... (more good info deleted)
brands/models. Does anyone have other recommendations?


Yes -- find a used machine tool dealer, and look for a serious
drill press -- with at least a MT-3 spindle. Plan to drive the drills
directly -- no chuck involved.


That's going to be my next step.

Expect that such a drill press will also probably need three
phase, so plan on building a rotary converter -- or hooking up VFD,
which will allow you to get even more speed control, as you can control
the motor speed directly, to supplement the belt reduction.


Nothing is as simple as I expected/hoped, oh well. Still, I recognize
good advice. Thanks!

...
Give us a clue where you are located, and perhaps we can point
you to a used equipment dealer known to do things right in your
vicinity.


Yes! Please! I'm in Red Bank, NJ (central NJ).

Thank you again for all the info!

A.
  #10   Report Post  
DoN. Nichols
 
Posts: n/a
Default Bench-top drill press recommendation? and what I found so far.

In article ,
wrote:
Hello again,


[ ... ]

Note that the 12" models can drill holes centered only 6" from
the nearest edge of the workpiece. If this is sufficient, fine.
Otherwise, consider larger, even if you are over your price limit.


The pieces I need to drill now are 1/16" thick (the 1" hole), and 1/8"
thick (smaller holes) and at most 1/2" from an edge, so size is not
an issue.


O.K. If these are not another example of the square tubing
which you mention later on, perhaps one of the heavier examples of the
Roper Whitney hole punches would be faster? I've never used on in
stainless. The smaller size goes up to 5/16" (IIRC) and can (with some
effort) make holes up to 3/16" in 1/8" aluminum. It might take too much
effort for stainless. Robin? You're the one who has done some punch
and die design work recently -- what are the odds of the larger Roper
Whitney handling 1/6" SS with a 1/2" hole? And how long would you
expect the punch and die to last?


... (lots of valuable info deleted )
Note that carbide drills in that size are *very* expensive, so
we'll calculate based on HSS. And I don't think that there are any
Silver & Demming (e.g. reduced shank) drills, in solid carbide, so HSS
is the most likely one for you.


I bought a set of 2 tapered bits, the first one to 1/2" and the second
from 1/2" to 1". These are to drill into 1/16" thick 316 stainless.
They are probably HSS (I don't have them nearby to check at the
moment, they cost $30).


These are the unibit style of bit -- though made under multiple
names by now. They are a nice choice for thin sheet metal, as you have
here. You can (except for the largest size) bring the bit on just a bit
farther, so you deburr the top side of the hole with the edge of the next
step.

The 1/8" 316 stainless will be drilled with smaller cobalt bits.

... (more good info deleted)
How many drill bits do you want to use per hole? Even the 280
RPM one is pushing things a bit for hobby work.


For the 1" holes, the two tapered bits I bought have something like 10
different sizes each, progressively larger. This, I presume, has the
same effect as using 20 progressively bigger drill bits.


In some ways -- yes. It will reduce the maximum torque needed,
as you will only be removing a little bit at a time. However, the
maximum spindle speed allowed is a function only of the diameter of the
hole, as the outer edge is moving faster than anything closer to the
center. Ideally -- you would do better with a variable speed decreasing
the speed as you move up each step -- but this becomes ridiculous fairly
quickly, so a speed set for the maximum diameter will have to do, even
if it is a bit slow with the rest.

Another benefit is that you have only one cutting flute, so the
torque is just that much smaller than the standard drill bit. All of
this makes it easier to supply sufficient pressure to keep it cutting.

Back when we didn't know how thick your workpieces would be, we
had to assume a standard format drill bit, and all the pressure which it
requires to feed. Adding the maximum thickness helps a lot.

You should get a good cutting fluid to keep buildup of metal
from the edge of the tool. And note that the sides of the steps will
rub on the edge of the hole to keep it centered. This might cause some
extra work-hardening at that surface, causing a bit more rapid wear to
the next step.

You may benefit from a TiN (Titanium Nitride) coating (looks
gold) on the step drills to help control metal buildup and supplement
the cutting fluid.

How thick is your stainless steel? You will want a minimum
stroke of probably at least a half inch longer than your workpiece
thickness with a 1" drill. You may need more if you have to lift the
workpiece out of fixturing, or if you need to change the drill bit
without disturbing the workpiece.


This is important, as the 1" holes are to go on opposing faces of 2"
square tube, so if I wanted to drill two holes without unclamping the
piece the stroke should be 2" plus the length of the tapered drill
bit. More than the small drill presses I was considering can do.


O.K. That is a problem -- especially as it can sometimes be
difficult to back one of these drills out which has gone all the way
through a hole. Also -- you'll need to either have two drill-press
vises to support it over the center hole of the table (if any), or to
hold it high enough -- or one larger drill press vise with enough
clearance between the rails for the drill to fully clear as it goes
through.

One thing to consider is that if you go all the way through from
one side, the exit side will have a burr on the outside where it can cut
someone with careless handling. Better if that is kept inside the tube.
(And to clean the burr off, you would need an even bigger countersink
bit than your hole. Maybe one of the countersinks which are a cone with
a hole drilled through at an angle to provide one cutting edge.

The alternative is to unclamp the piece and reverse it, but this
gets into issues of alignment and rigidity, as someone else pointed
out.


Since your total tool length is probably such that the tip, at
least, will start on the other side, this can be used to center the
workpiece after flipping. Hmmm ... 2" square tube? I'm not sure just
how long the working area of the 1" drill is. I only have a 0-1/2" one,
which I find really nice for holes in aluminum chassis materials. I've
never tried it in stainless. All of my stainless is too thick for that
kind of drill to make sense. (I also don't drill holes that large in
the stainless, normally. Biggest is 1/2", with a boring bar in the
lathe to enlarge it to minor thread diameter for 5/8-27 threads.

Anyway -- 2" square tubing is a bit large for a standard twist
drill which would be a good pilot for the Unibit. (Hmm ... again, what
is the smallest step on the 1" ones?) Perhaps a long drill bit of pilot
diameter to go through both sides in one pass, and then use that to
center both sides with the Unibit. This calls for a minimum stroke of
just a bit over 2" -- perhaps 2-1/2" would suffice.

... (more good info deleted)
brands/models. Does anyone have other recommendations?


Yes -- find a used machine tool dealer, and look for a serious
drill press -- with at least a MT-3 spindle. Plan to drive the drills
directly -- no chuck involved.


That's going to be my next step.

Expect that such a drill press will also probably need three
phase, so plan on building a rotary converter -- or hooking up VFD,
which will allow you to get even more speed control, as you can control
the motor speed directly, to supplement the belt reduction.


Nothing is as simple as I expected/hoped, oh well. Still, I recognize
good advice. Thanks!

...
Give us a clue where you are located, and perhaps we can point
you to a used equipment dealer known to do things right in your
vicinity.


Yes! Please! I'm in Red Bank, NJ (central NJ).


O.K. I guess that would suggest Dave Ficken (Mermac tools),
unless he has moved it all to Pa by now), and Dave Sobel. Dave Ficken
is on the web, but you'll probably never find Dave Sobel there.

I find myself reminded of a song by a friend who lives in
Middletown -- "The Long Branch Branch of the Red Bank bank". You might
never have encountered him, unless you are into the traditional music
scene.

Best of luck,
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 ---
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