Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Old May 13th 10, 11:08 PM posted to rec.crafts.metalworking
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Default Remember that o-ring groove in that piston?

Well, I tried to assemble the hole thing and the push rod threaded into my
piston crooked... How is that possible I wondered. I did everything on the
lathe. Oh, ****. No I didn't. My mini lathe was too small so I only
center drilled the piston on the lathe. I drilled it on the drill press. I
really need to throw this damn thing away. The table was tilted side to
side. I straightened that today, but found the table is also slightly
tilted front to back. GACK!!! Its not horrible for punching holes in
sheet, but I guess I need to add a mill drill to my wish list for anything
else.




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Old May 14th 10, 12:02 AM posted to rec.crafts.metalworking
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Default Remember that o-ring groove in that piston?

Since you haven't thrown the drill press away yet, why not take it on as
a challenge? Tram it in like a vertical mill. If it doesn't, take action.
I know that you won't do that again anyway, since you already owned
up to it here. Since you already had it in the lathe, that would be
the best place to drill the hole. I assume by saying "too small", you
mean "too short"?

One of the worst things that happens to me since the kids grew up and
left home many years ago is that when something goes wrong in the shop,
or if something is lost, I have no one to blame it on but me! Pretty
tough to take sometimes.

Actually, your post is a good wake up call for me, as I have never
trammed my own drill press. Worse than that, I have an X-Y table bolted
to the table 99% of the time, and, on top of that, I have another table,
made of wood, that is T-shaped so it can be quickly clmaped in the vise
mounted to the X-Y table. The leg of the "T" is a piece of 2X4.
How perpendicular can all that be?

Do inquiring (sp?) minds want to know?

Pete Stanaitis
---------------

Bob La Londe wrote:
Well, I tried to assemble the hole thing and the push rod threaded into
my piston crooked... How is that possible I wondered. I did everything
on the lathe. Oh, ****. No I didn't. My mini lathe was too small so I
only center drilled the piston on the lathe. I drilled it on the drill
press. I really need to throw this damn thing away. The table was
tilted side to side. I straightened that today, but found the table is
also slightly tilted front to back. GACK!!! Its not horrible for
punching holes in sheet, but I guess I need to add a mill drill to my
wish list for anything else.



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Old May 14th 10, 01:33 AM posted to rec.crafts.metalworking
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Default Remember that o-ring groove in that piston?

Bob La Londe wrote:
Well, I tried to assemble the hole thing and the push rod threaded into
my piston crooked... How is that possible I wondered. I did everything
on the lathe. Oh, ****. No I didn't. My mini lathe was too small so I
only center drilled the piston on the lathe. I drilled it on the drill
press. I really need to throw this damn thing away. The table was
tilted side to side. I straightened that today, but found the table is
also slightly tilted front to back. GACK!!! Its not horrible for
punching holes in sheet, but I guess I need to add a mill drill to my
wish list for anything else.


Next time, rough drill it undersized in the press, then bore the hole to
size, with a boring bar in the lathe.

I'm not sure about "too small", though -- unless the tailstock chuck
won't take the drill, you should be able to keep loads light by feeding
slowly.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
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Old May 14th 10, 01:42 AM posted to rec.crafts.metalworking
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Default Remember that o-ring groove in that piston?

"Tim Wescott" wrote in message
...
Bob La Londe wrote:
Well, I tried to assemble the hole thing and the push rod threaded into
my piston crooked... How is that possible I wondered. I did everything
on the lathe. Oh, ****. No I didn't. My mini lathe was too small so I
only center drilled the piston on the lathe. I drilled it on the drill
press. I really need to throw this damn thing away. The table was
tilted side to side. I straightened that today, but found the table is
also slightly tilted front to back. GACK!!! Its not horrible for
punching holes in sheet, but I guess I need to add a mill drill to my
wish list for anything else.


Next time, rough drill it undersized in the press, then bore the hole to
size, with a boring bar in the lathe.

I'm not sure about "too small", though -- unless the tailstock chuck won't
take the drill, you should be able to keep loads light by feeding slowly.


Actually it has an amazing amount of power for a cheap tiny lathe. HF calls
it a 7 X 10, but I think its really a 7 x 8. Several people on-line have
commented that when they swap out to the 14" bed from The Little Machine
Shop they gain about 6 inches of working length rather than the 4 you would
expect. As soon as they are back in stock I plan to order the longer bed
for it, and turn the old bed into a tail stock parking rest. I still want a
bigger lathe but this little one is handy sometimes.

Now to save that piston... I am thinking I might bore it out further,
hammer in a plug, and re drill it concentrically. Then either drive in a
couple wedge pins or just slap a couple weld tacks on it.




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Old May 14th 10, 01:51 AM posted to rec.crafts.metalworking
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Posts: 3,146
Default Remember that o-ring groove in that piston?

On May 13, 6:08*pm, "Bob La Londe" wrote:
...I drilled it on the drill press. *I
really need to throw this damn thing away. *The table was tilted side to
side. *I straightened that today, but found the table is also slightly
tilted front to back. *GACK!!! *...


Long before I found a mill I fixed my cheap drill press by making the
head slide down the column so I didn't need the table, only the
squarer base. It can also be clamped to a large beam or plate to drill
it.

jsw


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Old May 14th 10, 03:48 AM posted to rec.crafts.metalworking
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Posts: 6,746
Default Remember that o-ring groove in that piston?


Bob La Londe wrote:

"Tim Wescott" wrote in message
...
Bob La Londe wrote:
Well, I tried to assemble the hole thing and the push rod threaded into
my piston crooked... How is that possible I wondered. I did everything
on the lathe. Oh, ****. No I didn't. My mini lathe was too small so I
only center drilled the piston on the lathe. I drilled it on the drill
press. I really need to throw this damn thing away. The table was
tilted side to side. I straightened that today, but found the table is
also slightly tilted front to back. GACK!!! Its not horrible for
punching holes in sheet, but I guess I need to add a mill drill to my
wish list for anything else.


Next time, rough drill it undersized in the press, then bore the hole to
size, with a boring bar in the lathe.

I'm not sure about "too small", though -- unless the tailstock chuck won't
take the drill, you should be able to keep loads light by feeding slowly.


Actually it has an amazing amount of power for a cheap tiny lathe. HF calls
it a 7 X 10, but I think its really a 7 x 8. Several people on-line have
commented that when they swap out to the 14" bed from The Little Machine
Shop they gain about 6 inches of working length rather than the 4 you would
expect. As soon as they are back in stock I plan to order the longer bed
for it, and turn the old bed into a tail stock parking rest. I still want a
bigger lathe but this little one is handy sometimes.

Now to save that piston... I am thinking I might bore it out further,
hammer in a plug, and re drill it concentrically. Then either drive in a
couple wedge pins or just slap a couple weld tacks on it.



Bore it out oversized and concentric, tap it, and either use a larger
rod, or an internal/external threaded bushing.
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Old May 14th 10, 04:13 PM posted to rec.crafts.metalworking
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Posts: 523
Default Remember that o-ring groove in that piston?

Seems to me a drill press out of tram, even with a tilted table, would only tend to drill larger
holes - not holes at the angle of tilt.

Bob Swinney
"Bob La Londe" wrote in message ...
Well, I tried to assemble the hole thing and the push rod threaded into my
piston crooked... How is that possible I wondered. I did everything on the
lathe. Oh, ****. No I didn't. My mini lathe was too small so I only
center drilled the piston on the lathe. I drilled it on the drill press. I
really need to throw this damn thing away. The table was tilted side to
side. I straightened that today, but found the table is also slightly
tilted front to back. GACK!!! Its not horrible for punching holes in
sheet, but I guess I need to add a mill drill to my wish list for anything
else.



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Old May 14th 10, 04:55 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Feb 2010
Posts: 204
Default Remember that o-ring groove in that piston?

Bob La Londe wrote:
"Tim Wescott" wrote in message
...
Bob La Londe wrote:
Well, I tried to assemble the hole thing and the push rod threaded
into my piston crooked... How is that possible I wondered. I did
everything on the lathe. Oh, ****. No I didn't. My mini lathe was
too small so I only center drilled the piston on the lathe. I
drilled it on the drill press. I really need to throw this damn
thing away. The table was tilted side to side. I straightened that
today, but found the table is also slightly tilted front to back.
GACK!!! Its not horrible for punching holes in sheet, but I guess I
need to add a mill drill to my wish list for anything else.


Next time, rough drill it undersized in the press, then bore the hole
to size, with a boring bar in the lathe.

I'm not sure about "too small", though -- unless the tailstock chuck
won't take the drill, you should be able to keep loads light by
feeding slowly.


Actually it has an amazing amount of power for a cheap tiny lathe. HF
calls it a 7 X 10, but I think its really a 7 x 8. Several people
on-line have commented that when they swap out to the 14" bed from The
Little Machine Shop they gain about 6 inches of working length rather
than the 4 you would expect. As soon as they are back in stock I plan
to order the longer bed for it, and turn the old bed into a tail stock
parking rest. I still want a bigger lathe but this little one is handy
sometimes.

Now to save that piston... I am thinking I might bore it out further,
hammer in a plug, and re drill it concentrically. Then either drive in
a couple wedge pins or just slap a couple weld tacks on it.


(a) Press in a plug -- even doing this in a vise is going to be more
accurate than hammering it in.

(b) How much force on the piston, and which way? If the piston isn't
going to be pulling hard on the rod, a press fit or shrink fit may be
plenty strong enough. Or a light press fit with one of the more
insanely strong Loctites, or epoxy. Or just fill the hole with epoxy &
call it a plug (hmm).

(c) Press, weld (not if it's epoxy, though), _then_ bore out the hole --
and check the outside for concentricity and warps, too.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
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Old May 14th 10, 05:10 PM posted to rec.crafts.metalworking
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Posts: 652
Default Remember that o-ring groove in that piston?

"Tim Wescott" wrote in message
...
Bob La Londe wrote:
"Tim Wescott" wrote in message
...
Bob La Londe wrote:
Well, I tried to assemble the hole thing and the push rod threaded into
my piston crooked... How is that possible I wondered. I did
everything on the lathe. Oh, ****. No I didn't. My mini lathe was
too small so I only center drilled the piston on the lathe. I drilled
it on the drill press. I really need to throw this damn thing away.
The table was tilted side to side. I straightened that today, but
found the table is also slightly tilted front to back. GACK!!! Its
not horrible for punching holes in sheet, but I guess I need to add a
mill drill to my wish list for anything else.

Next time, rough drill it undersized in the press, then bore the hole to
size, with a boring bar in the lathe.

I'm not sure about "too small", though -- unless the tailstock chuck
won't take the drill, you should be able to keep loads light by feeding
slowly.


Actually it has an amazing amount of power for a cheap tiny lathe. HF
calls it a 7 X 10, but I think its really a 7 x 8. Several people
on-line have commented that when they swap out to the 14" bed from The
Little Machine Shop they gain about 6 inches of working length rather
than the 4 you would expect. As soon as they are back in stock I plan to
order the longer bed for it, and turn the old bed into a tail stock
parking rest. I still want a bigger lathe but this little one is handy
sometimes.

Now to save that piston... I am thinking I might bore it out further,
hammer in a plug, and re drill it concentrically. Then either drive in a
couple wedge pins or just slap a couple weld tacks on it.


(a) Press in a plug -- even doing this in a vise is going to be more
accurate than hammering it in.


Well, the little 12 ton air over press would have probably been my tool of
choice too, but I might not have thought of it until too late

(b) How much force on the piston, and which way?


Not all that much. (maybe 20 or 30 if there is a plug up) If the guide rod
is straight it's will have a few pounds of vacuum in one direction as it
draws in material and a few more of pressure as it pushed out material.
Right now its hand operated, but the dimensions are planned for it to be
able to drop into an electric caulking gun. (different piston entirely when
I do that conversion)

If the piston isn't going to be pulling hard on the rod, a press fit or
shrink fit may be plenty strong enough. Or a light press fit with one of
the more insanely strong Loctites, or epoxy. Or just fill the hole with
epoxy & call it a plug (hmm).



I'll have to thank about that. Epoxy would work for strength, but this is
an aluminum hand injector that may be handling liquid media upto about 400
degrees... Ideally the media should never run above about 350, but my
thermal remote tells me its hitting 400 occasionally. You know I bought
that thermal remote for checking the preheat on welding thicker aluminum
plate, and since then I have used it for all kinds of things.



(c) Press, weld (not if it's epoxy, though), _then_ bore out the hole --
and check the outside for concentricity and warps, too.


A few thousandths wouldn't hurt a thing. There is a lot of clearance on
this piston. The o-rings fill the gap. The degree of accuracy for the push
rod to be perpendicular to the piston o-rings is important though. I
already have a rod guide, but can't use it the way it is. If it doesn't go
in and out straight the piston will lose suction or pressure out the back.


--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com


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Old May 14th 10, 05:36 PM posted to rec.crafts.metalworking
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First recorded activity by DIYBanter: Feb 2010
Posts: 204
Default Remember that o-ring groove in that piston?

Bob La Londe wrote:
"Tim Wescott" wrote in message
...
Bob La Londe wrote:
"Tim Wescott" wrote in message
...
Bob La Londe wrote:
Well, I tried to assemble the hole thing and the push rod threaded
into my piston crooked... How is that possible I wondered. I did
everything on the lathe. Oh, ****. No I didn't. My mini lathe
was too small so I only center drilled the piston on the lathe. I
drilled it on the drill press. I really need to throw this damn
thing away. The table was tilted side to side. I straightened that
today, but found the table is also slightly tilted front to back.
GACK!!! Its not horrible for punching holes in sheet, but I guess
I need to add a mill drill to my wish list for anything else.

Next time, rough drill it undersized in the press, then bore the
hole to size, with a boring bar in the lathe.

I'm not sure about "too small", though -- unless the tailstock chuck
won't take the drill, you should be able to keep loads light by
feeding slowly.

Actually it has an amazing amount of power for a cheap tiny lathe.
HF calls it a 7 X 10, but I think its really a 7 x 8. Several people
on-line have commented that when they swap out to the 14" bed from
The Little Machine Shop they gain about 6 inches of working length
rather than the 4 you would expect. As soon as they are back in
stock I plan to order the longer bed for it, and turn the old bed
into a tail stock parking rest. I still want a bigger lathe but this
little one is handy sometimes.

Now to save that piston... I am thinking I might bore it out
further, hammer in a plug, and re drill it concentrically. Then
either drive in a couple wedge pins or just slap a couple weld tacks
on it.


(a) Press in a plug -- even doing this in a vise is going to be more
accurate than hammering it in.


Well, the little 12 ton air over press would have probably been my tool
of choice too, but I might not have thought of it until too late

(b) How much force on the piston, and which way?


Not all that much. (maybe 20 or 30 if there is a plug up) If the guide
rod is straight it's will have a few pounds of vacuum in one direction
as it draws in material and a few more of pressure as it pushed out
material. Right now its hand operated, but the dimensions are planned
for it to be able to drop into an electric caulking gun. (different
piston entirely when I do that conversion)

If the piston isn't going to be pulling hard on the rod, a press fit
or shrink fit may be plenty strong enough. Or a light press fit with
one of the more insanely strong Loctites, or epoxy. Or just fill the
hole with epoxy & call it a plug (hmm).



I'll have to thank about that. Epoxy would work for strength, but this
is an aluminum hand injector that may be handling liquid media upto
about 400 degrees... Ideally the media should never run above about
350, but my thermal remote tells me its hitting 400 occasionally. You
know I bought that thermal remote for checking the preheat on welding
thicker aluminum plate, and since then I have used it for all kinds of
things.



(c) Press, weld (not if it's epoxy, though), _then_ bore out the hole
-- and check the outside for concentricity and warps, too.


A few thousandths wouldn't hurt a thing. There is a lot of clearance on
this piston. The o-rings fill the gap. The degree of accuracy for the
push rod to be perpendicular to the piston o-rings is important though.
I already have a rod guide, but can't use it the way it is. If it
doesn't go in and out straight the piston will lose suction or pressure
out the back.


In that case, were it me and had I a welder handy that would work on the
material, I'd bore it out to some (over) size, press a plug, weld, then
do it right.

Which is starting to sound like it's as much work as just making another
piston, if it's fairly simple. Maybe you should put the current one
into the trophy case as a reminder, and just make another one?

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com


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