A while back, I asked about enlarging holes in 1/4" thick stainless plate
(Type 316). Here's a summary of the job I've been tasked with:

There are forty-four stainless square support posts. Each post has a base
consisting of two pieces of 1/4" thick stainless angle plate; the plates are
welded along the bottom of the posts, one on each side. Like this:

H
H
_]H[_

The two horizontal flanges that make up the base each have two holes (four
holes per post) for bolting the base to a concrete pad. The holes were
drilled 1/2" by the factory, but need to be 13/16". That's where we left off
in my last request for advice in this newsgroup.

Now I find out the job might be trickier.

Two of the holes may be too close to the forward edge of the plate after
enlargement (still awaiting further info from the customer). If so, then
half the holes (88 of the 176) will not only have to be enlarged, but will
need to be offset so that the resulting enlarged hole is no closer to the
forward edge of the base plate as it is now.

Any ideas on the best way to do this? I have access to a Rong Fu Mill-Drill.

If this were plain carbon steel, I'd probably use an end mill to "drill" the
hole on a new center. But I'm not sure how well that will work with 316
stainless.

Thanks for your advice!
Michael

....
Any ideas on the best way to do this? I have access to a Rong Fu
Mill-Drill.

If this were plain carbon steel, I'd probably use an end mill to "drill"
the hole on a new center. But I'm not sure how well that will work with
316 stainless.

Right idea. Wrong machine. I've never used one of these Rong Fus so I don't
know for certain, but I don't see how they would be anywhere near rigid
enough. Be sure and use a low speed and a high feed when you do this. You
don't want to workharden the cut.

You'll want a few spare endmills. Personally, I'd use 2 flute HSS here. But
others may disagree.

Karl

"DeepDiver" wrote in message
...

snip


Thanks for your advice!


Suggest dont give up your day job just yet.

--

SVL

"Karl Townsend" remove .NOT to reply wrote
in message ink.net...

Right idea. Wrong machine. I've never used one of these Rong Fus so I
don't know for certain, but I don't see how they would be anywhere near
rigid enough.

Well, that's the only mill I have available (unless we farm the job out to a
professional shop). In which case, my part in the whole problem is finished.

But actually, there is one advantage mill-drills have over their larger
brethren for jobs like this: you can swing the head on the column. Normally,
that is considered a disadvantage (and I agree) because you can't make
z-axis changes without losing your zero. But for this job, I have to get to
the holes from the bottom of the plate because they are too close
(horizontally) to the post to get to them from the top. I don't know of many
home-shop mills out there that can fit a 48" post under the mill head. But
with the mill-drill, I can clamp this part upside down, with base on the
edge of the milling table and the post off the side (hanging towards the
ground), and then swing the head over to get to the holes.


Personally, I'd use 2 flute HSS here.

Why two-flute instead of four-flute?


Thanks,
Michael

On Wed, 13 Apr 2005 11:16:26 GMT, "DeepDiver"
wrote:

A while back, I asked about enlarging holes in 1/4" thick stainless plate
(Type 316). Here's a summary of the job I've been tasked with:

There are forty-four stainless square support posts. Each post has a base
consisting of two pieces of 1/4" thick stainless angle plate; the plates are
welded along the bottom of the posts, one on each side. Like this:

H
H
_]H[_

The two horizontal flanges that make up the base each have two holes (four
holes per post) for bolting the base to a concrete pad. The holes were
drilled 1/2" by the factory, but need to be 13/16". That's where we left off
in my last request for advice in this newsgroup.

Now I find out the job might be trickier.

Two of the holes may be too close to the forward edge of the plate after
enlargement (still awaiting further info from the customer). If so, then
half the holes (88 of the 176) will not only have to be enlarged, but will
need to be offset so that the resulting enlarged hole is no closer to the
forward edge of the base plate as it is now.

Any ideas on the best way to do this? I have access to a Rong Fu Mill-Drill.

If this were plain carbon steel, I'd probably use an end mill to "drill" the
hole on a new center. But I'm not sure how well that will work with 316
stainless.

Thanks for your advice!
Michael

Plasma cutter

Gunner

Rule #35
"That which does not kill you,
has made a huge tactical error"

If you had a plasma cutter, you would not have asked the question. So
I am assuming that you don't. The Drill / Mill should work well once
you figure out how to clamp the part. Lowering the head so the column
is short will help on the rigidity.

The best way would be to use a hole saw or a 13/16th drill. Drilling
is one of the most efficient ways to remove metal. The forces are
balanced and both lips are continuously cutting. Use coolant and
fairly low speed. Be sure to keep cutting at a feed fast enough that
you are under the metal that has been work hardened on the previous
revolution. Not feeding enough is a mistake. If you have to sharpen
your drill, give it a little extra clearance.

Carpenter Tech has a great booklet on machining Stainless Steel.

Dan

On Wed, 13 Apr 2005 14:31:28 GMT, "DeepDiver"
wrote:

"Karl Townsend" remove .NOT to reply wrote
in message ink.net...

Right idea. Wrong machine. I've never used one of these Rong Fus so I
don't know for certain, but I don't see how they would be anywhere near
rigid enough.

Well, that's the only mill I have available (unless we farm the job out to a
professional shop). In which case, my part in the whole problem is finished.

I'm beginning to think that you need to do just that.

But actually, there is one advantage mill-drills have over their larger
brethren for jobs like this: you can swing the head on the column. Normally,
that is considered a disadvantage (and I agree) because you can't make
z-axis changes without losing your zero. But for this job, I have to get to
the holes from the bottom of the plate because they are too close
(horizontally) to the post to get to them from the top. I don't know of many
home-shop mills out there that can fit a 48" post under the mill head.

Actually there's a good number of them out there. They're called
horizontal mills and this job pretty much screams for one.

I've got a good bit of experience plunging end mills into a
interrupted cut in 316 SS and I must say that I have serious doubts
about a mill-drills rigidity being good enough. I was doing it on a
huge Cincinnati #3 horizontal mill that weighed about 8000lbs and I
was wishing for more rigidity.

But
with the mill-drill, I can clamp this part upside down, with base on the
edge of the milling table and the post off the side (hanging towards the
ground), and then swing the head over to get to the holes.


Personally, I'd use 2 flute HSS here.

Why two-flute instead of four-flute?


Less force required to maintain a heavy enough chip. Two flutes
plunge better than four flutes. However since you're just reaming a 4
flute may work better so you'll just have to try both to see what
you're machine likes the best.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

"Wayne Cook" wrote in message
...
On Wed, 13 Apr 2005 14:31:28 GMT, "DeepDiver"
wrote:

Actually there's a good number of them out there. They're called
horizontal mills and this job pretty much screams for one.

I realize there are mills available better suited to this job. What I said
was that they are not commonly found in a home shop.


I've got a good bit of experience plunging end mills into a
interrupted cut in 316 SS and I must say that I have serious doubts
about a mill-drills rigidity being good enough.

I too have my concerns, which is why I posted the question. I'm not above
saying that I can't do this job (actually, a favor for a friend).


I was doing it on a huge Cincinnati #3 horizontal mill that
weighed about 8000lbs and I was wishing for more rigidity.

I'm fairly certain there's not a single machine of that caliber anywhere
within 30 miles radius of me. How far beyond, I don't know.


Thanks.

"PrecisionMachinisT" wrote in message
...

Suggest dont give up your day job just yet.

Thanks, that was very helpful.

When I wrote "job", I was using that term in the context of a "task", not a
means of employment. I'm trying to help out a friend who's in a jam.

"Gunner" wrote in message
...

Plasma cutter

Just out of curiosity, how "clean" is the cut made by a plasma cutter? I
don't think the edge finish would be acceptable to the final "customer".
Furthermore, he would want a nicely-shaped round hole so that would mean a
robotic plasma cutter.

Thanks

Personally, I'd use 2 flute HSS here.

Why two-flute instead of four-flute?

Why HSS instead of carbide? I bought some Atrax carbide endmills
from Enco sale flyers and they are awesome in SS.

cs

"Chuck Sherwood" wrote in message
...
Personally, I'd use 2 flute HSS here.

Why two-flute instead of four-flute?

Why HSS instead of carbide? I bought some Atrax carbide endmills
from Enco sale flyers and they are awesome in SS.


The problem with carbide is that if your set-up and machine are not
rock-solid rigid, the carbide will fracture. HSS tends to be more forgiving.

- Michael

The problem with carbide is that if your set-up and machine are not
rock-solid rigid, the carbide will fracture. HSS tends to be more
forgiving.

Agreed. And rock solid really means rock solid... Any chatter or movement
at all - including simple vibration of the unit can ruin expensive tooling
fast and furiously.

Another problem I've only read about is that Carbide tends to micro-fracture
if coolant is needed but not used properly. The very tip of the carbide
simply doesn't get cooled properly due to vaporization of the coolant around
the area being cut, etc. Micro-fractures lead to not-so-micro fractures and
then chipping, etc.

Regards,
Joe Agro, Jr.
(800) 871-5022
http://www.AutoDrill.com
http://www.Multi-Drill.com

V8013

Take a piece of plywood and cut a nicely shaped hole in it somewhat
larger than your 13/16th hole. Clamp it to the stainless and use it
for a guide for the plasma torch.

Try to find someone with a plasma torch in your area and look at some
of the stuff they have cut. Plasma is often used to make silhouette
lawn art.

Dan

On Wed, 13 Apr 2005 19:48:33 GMT, "DeepDiver"
wrote:

"Wayne Cook" wrote in message
.. .
On Wed, 13 Apr 2005 14:31:28 GMT, "DeepDiver"
wrote:

Actually there's a good number of them out there. They're called
horizontal mills and this job pretty much screams for one.

I realize there are mills available better suited to this job. What I said
was that they are not commonly found in a home shop.

What I was saying is that there's a lot of home shop machinists out
there with horizontal mills. They tend to be cheap so there's a fair
number that get snapped up by people with the room for them.


I've got a good bit of experience plunging end mills into a
interrupted cut in 316 SS and I must say that I have serious doubts
about a mill-drills rigidity being good enough.

I too have my concerns, which is why I posted the question. I'm not above
saying that I can't do this job (actually, a favor for a friend).


I'm not saying you can't do it either. But I think you may be in for
more grief and expense in tooling than the job is worth. That's a
pretty tough job with the right machines. There's a chance you could
do it with a mill drill but be prepared to buy a fair number of end
mills and possibly have some other trouble as well.


I was doing it on a huge Cincinnati #3 horizontal mill that
weighed about 8000lbs and I was wishing for more rigidity.

I'm fairly certain there's not a single machine of that caliber anywhere
within 30 miles radius of me. How far beyond, I don't know.


For reference I bought that same machine at my former employers
auction for $500 and then later sold it for $1000.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

Chuck Sherwood wrote:

Personally, I'd use 2 flute HSS here.


Why two-flute instead of four-flute?



Why HSS instead of carbide? I bought some Atrax carbide endmills
from Enco sale flyers and they are awesome in SS.


The interrupted cut is hard on carbide. Use M42 or M57 HSS, that's
HSS plus cobalt. The M42, etc. is a LOT tougher than plain HSS, but
also extremely tolerant of interrupted cuts, which the carbide has a problem
with, especially when things are not rigid.

I have doubts about the Rong-Fu. I am pretty confident I could do this on
my Bridgeport, although I'd probably have to baby it some to keep from
trashing the cutters. I might try with 4-flute, as they are a little
more rigid
(thicker web) and you are not going to cut fast enough to fill the flutes.

Jon

"Wayne Cook" wrote in message
...
On Wed, 13 Apr 2005 19:48:33 GMT, "DeepDiver"
wrote:

What I was saying is that there's a lot of home shop machinists out
there with horizontal mills. They tend to be cheap so there's a fair
number that get snapped up by people with the room for them.

I forgot you were in Texas where everything is BIGGER (including your home
machine shops, I guess).

Seriously, I didn't realize that these machines were popular among home
machinists; I thought they were prohibitivly large. Everyone I know who
works in a home shop uses some form of vertical mill.


I'm not saying you can't do it either. But I think you may be in for
more grief and expense in tooling than the job is worth. That's a
pretty tough job with the right machines. There's a chance you could
do it with a mill drill but be prepared to buy a fair number of end
mills and possibly have some other trouble as well.

I realize that. I'm still not sure if it's feasible myself. I'm hoping the
job doesn't require moving the center of the holes. Simply enlarging them
was the original proposal and I'm fairly confident I can do that. If the
holes do need to be re-centered, I may just pass on the "job".


For reference I bought that same machine at my former employers
auction for $500 and then later sold it for $1000.

Sadly, the liberals and lawyers have driven most of the big manufacturing
industry out of California. So my choices are more limited.

Thanks again for your feedback!
Michael

On Thu, 14 Apr 2005 01:18:37 GMT, "DeepDiver"
wrote:

"Wayne Cook" wrote in message
.. .
On Wed, 13 Apr 2005 19:48:33 GMT, "DeepDiver"
wrote:

What I was saying is that there's a lot of home shop machinists out
there with horizontal mills. They tend to be cheap so there's a fair
number that get snapped up by people with the room for them.

I forgot you were in Texas where everything is BIGGER (including your home
machine shops, I guess).

True. :-)

Seriously, I didn't realize that these machines were popular among home
machinists; I thought they were prohibitivly large. Everyone I know who
works in a home shop uses some form of vertical mill.

Not all horizontal mills are large. Even the small ones are more
rigid than many vertical mills. I can remember dozens of people who
are either on this group or have been on it that have horizontal
mills. Some have added vertical heads to them to make them more
versatile while other mills like mine are combination horizontal and
vertical.


I'm not saying you can't do it either. But I think you may be in for
more grief and expense in tooling than the job is worth. That's a
pretty tough job with the right machines. There's a chance you could
do it with a mill drill but be prepared to buy a fair number of end
mills and possibly have some other trouble as well.

I realize that. I'm still not sure if it's feasible myself. I'm hoping the
job doesn't require moving the center of the holes. Simply enlarging them
was the original proposal and I'm fairly confident I can do that. If the
holes do need to be re-centered, I may just pass on the "job".

Agreed though I still have the speed concerns we discussed earlier.


For reference I bought that same machine at my former employers
auction for $500 and then later sold it for $1000.

Sadly, the liberals and lawyers have driven most of the big manufacturing
industry out of California. So my choices are more limited.


That's funny. I'm always envious of you guys living in California
have such easy access to cheap machines. Machines in this area are
extremely scarce and normally bring premium prices because of this.


Seriously I see more machines available in California and the East
coast when I look on ebay than any other place.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

Seriously, I didn't realize that these machines were popular among home
machinists; I thought they were prohibitivly large. Everyone I know who
works in a home shop uses some form of vertical mill.

I think Horizontal mills are gaining popularity. I know a couple
hobbyists that own them. One added a bridgeport M-head so that he
can use it as a vertical mill two. I personally own two horizontal
mills and I find them very useful machines.

chuck

Wayne Cook wrote:
... Not all horizontal mills are large. Even the small ones are more
rigid than many vertical mills. ...

But as soon as you switch to end mills (per the the OP's requirement),
you lose a lot of the horizontal's rigidity. I.e., the cutter is no
longer supported at both ends. Bob

But as soon as you switch to end mills (per the the OP's requirement),
you lose a lot of the horizontal's rigidity. I.e., the cutter is no
longer supported at both ends. Bob

I think a horizonal mill is still much more rigid than a vertical
mill for a number of reasons. First, even my small clausing horizontal
mill have a #30 taper which is much heavier than an R8 or MT2
vertical spindle. Second, the spindle is in the column which is
directly attached to the knee. A lot more stuff is between the
table and the spindle in a vertical mill.

Using an endmill in the horizontal I can plung with the Y axis,
which is probably more rigid than plunging with the quill on most
vertical machines and definately more rigid than the quill on a mill
drill. I know because I got the big Jet mill drill and its no
comparison to my rockwell horizontal. Another big plus is that the
rockwell has almost 7 inchs of Y travel which is more than any
vertical mill I have ever used.

Vertical mills are very useful, Horizontal mills just rock.

chuck

On 14 Apr 2005 15:35:16 GMT, (Chuck
Sherwood) wrote:

But as soon as you switch to end mills (per the the OP's requirement),
you lose a lot of the horizontal's rigidity. I.e., the cutter is no
longer supported at both ends. Bob

I think a horizonal mill is still much more rigid than a vertical
mill for a number of reasons. First, even my small clausing horizontal
mill have a #30 taper which is much heavier than an R8 or MT2
vertical spindle. Second, the spindle is in the column which is
directly attached to the knee. A lot more stuff is between the
table and the spindle in a vertical mill.

Using an endmill in the horizontal I can plung with the Y axis,
which is probably more rigid than plunging with the quill on most
vertical machines and definately more rigid than the quill on a mill
drill. I know because I got the big Jet mill drill and its no
comparison to my rockwell horizontal. Another big plus is that the
rockwell has almost 7 inchs of Y travel which is more than any
vertical mill I have ever used.

Vertical mills are very useful, Horizontal mills just rock.

What he said.

Very good post.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook

"DeepDiver" wrote in message
...
"PrecisionMachinisT" wrote in message
...

Suggest dont give up your day job just yet.

Thanks, that was very helpful.

When I wrote "job", I was using that term in the context of a "task", not
a
means of employment. I'm trying to help out a friend who's in a jam.


I already figgered this much out on my own...

Curious, what you spose does it have to do with anything ???

--

SVL

"PrecisionMachinisT" wrote in message
...

"DeepDiver" wrote in message
...
"PrecisionMachinisT" wrote in message
...

Suggest dont give up your day job just yet.

Thanks, that was very helpful.

When I wrote "job", I was using that term in the context of a "task",
not a means of employment. I'm trying to help out a friend who's in
a jam.

I already figgered this much out on my own...

Curious, what you spose does it have to do with anything ???


Dear PrecisionMachinisT,

Please forgive my error in asking for machining advice in this newsgroup; I
was under the mistaken impression that it existed for that purpose. I hope I
didn't offend your delicate sensibilities with my question. From your posts,
I now realize that this newsgroup must really be for arrogant jerks to make
snide comments with no educational or instructive value. Thank you for
enlightening me.

P.S. You may be a brilliant machinist, but you could really use some lessons
in character (not to mention English grammar, spelling, and punctuation).

Regards,
Michael

"DeepDiver" wrote in message
...
"PrecisionMachinisT" wrote in message
...

"DeepDiver" wrote in message
...
"PrecisionMachinisT" wrote in message
...

Suggest dont give up your day job just yet.

Thanks, that was very helpful.

When I wrote "job", I was using that term in the context of a "task",
not a means of employment. I'm trying to help out a friend who's in
a jam.

I already figgered this much out on my own...

Curious, what you spose does it have to do with anything ???


Dear PrecisionMachinisT,

Please forgive my error in asking for machining advice in this newsgroup;
I
was under the mistaken impression that it existed for that purpose. I hope
I
didn't offend your delicate sensibilities with my question. From your
posts,
I now realize that this newsgroup must really be for arrogant jerks to
make
snide comments with no educational or instructive value. Thank you for
enlightening me.

P.S. You may be a brilliant machinist, but you could really use some
lessons
in character (not to mention English grammar, spelling, and punctuation).


Just that over time Ive learned to not offer help to someone where it will
involve my needing to ask others for help in turn.

Out of respect for those that have helped me, I wont put them out by asking
them to help me to help someone else.

As to my writing style, that is by choice.

Now you can feel free to me all about character one more time.

--

SVL

I have a friend with a Hyperterm Powermax 600 - (Like I have now :-) ) and his wife
used a pine cut out figure to trace around. The plasma was cutting thin steel,
but didn't burn up the pine.

Now for me to try.

Martin
--
Martin Eastburn
@ home at Lion's Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

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