开云体育

Folks,

After having shimmed up my first tool in my std. toolpost (using a spare
butt hinge and laminations from a disassembled transformer), the desire
(no, NEED) for fabricating an alternative to the problem of shimming is
screming loud and clear. I've got a question about an alternative (middle
of the road) solution. I'll call it the Shim Screw Tool Post. For some
reason, the sound of that rolling off my toung brings 'Scrimshaw' to
mind. Oh well, on to my question.

How about adding shim screws to the bottom plate of the std. tool post?
They would be used for adjusting the height of tools where you would
normally use shims. This still allows each tool to be set to a different
height. The heads of the shim screws would need to be at least as large as
the tool being supported.

I can't believe this idea has not already been thought of long before now
so I can't officially take all the credit. I've submitted a couple of pics
for your review under "Rance's Stuff". I'm gonna go ahead and post this
before the pics are uploaded in hopes that they won't be rejected. (I'm
really not trying to push the moderators here :) ).

I'm guessing that tool stability would be the first, and biggest concern.
I truly believe that quantity and careful choice of shim-screw size could
overcome that objection though.

The only initial downside that I can see is that for some tool holder
accessories (appendages, you might call them) is that the rigidity for
THOSE might be reduced (depending on their design). But then I can see
that it won't affect ALL those designs. I can add more pics to clairify if
needed.

With this design, the less experienced machinist could build more holders
at a lower cost using fewer tool bits (ie. dovetail cutter) than the
sexier 'one-tool-per-holder' QCTP's. And it can ALL be done on the lathe!
:) I really like that since I don't have a mill and don't see one in the
near future.

If working with shorter tool posts (7x12 vs 8x12) I could imagine using
headless screws and adjusting them from underneath the tool post using an
allen wrench. "How" you ask, "would you then adjust the tool?". I could
imagine setting the tool post upside down on a flat surface and setting
the tool height (away from the lathe, at your workbench). A picture would
be worth 1000 words here. I'll submit one if needed.

My drawings are NOT to scale. This idea also comes from my ONLY first-hand
experience which is with my new 8x12 which might be considerably different
than the more common 7x12's.

I'm REALLY interested in your opinions on this so please fire away with
your comments, suggestions, concerns. Thanks in advance.

Rance (the redneck)

Thanks Ron, and to Clint for posting the pics.

I went to the local scrap yard (for the 1st time) and found a
plethora of alum. scraps. I got 2' of 1.5" bar stock and a 6"x1"
square plate for starters. I'm gonna be going back there often. :)
I'll go ahead and fine-tune my shimming for this first tool but the
first thing I want to do is to build a new tool post as I've
described.

Ron, others, would you think that al. would be sufficient for this or
does it have to be steel? The toolpost that comes with the 8x12 seems
huge. I would think that an alum. one of the same dimensions would be
fine.

Also Ron, did you have any problems with the mounted tool bit
twisting while using your set screw configuration? Clint had
expressed concern of rigidity.

Rance


--- In 7x12minilathe@..., "Ronald Durbin"
<trainguy_347@...> wrote:

I have done this with a smaller post, except that
I used set screws (or grub screws, as our British brothers and

sisters

call them) comming up from the bottom. To adjust, just undo the
retaining nut on top, lift up the post, back off the top screw
slightly, engage (run further in) the bottom screw tightly, and
replace the post as per normal. This sometimes take a few tries,

but

once the height is achieved, all is well. Great drawings, by the

way!.

Ron.

Hi, Rance. Aluminum (aluminium) is strong, but it has been my experience that threaded holes are easily stripped or deformed with twisting motions. Steel would probably be best. As for the stability, try using a shimming block against the inside vertical surface of the tool, between it and the tool post. Good luck, Ron.


---- rancerupp <rupps@...> wrote:

Thanks Ron. So how about using threaded inserts in an aluminum block?
First downside I see with an insert it creates an additional place
for possible lost rigidity. I've seen Pem Nuts for 6-32 screws in
1/16" alum. pate. Has anyone seen similar for 3/16 or 1/4 inch bolts?
T-Nuts come to mind, but those are for wood. If the threads are the
only forseeable problem, then I'd prefer to use alum.

As for rigidity, my toolpost is 2 3/4 square and 1 5/8 high. Top lip
is a bit over 1/2, the middle slot is about 3/4, the bottom lip is a
bit over 1/4. The middle slot is about 1/2 in from the outer edge.
With that, the shortest threaded insert would be for the bottom
(1/4").

Good point about shimming the sides. I have some ideas on that but
I'll wait before introducing those.

Anyone know of sources for threaded steel inserts? Thanks.

Rance


--- In 7x12minilathe@..., <trainguy_347@...> wrote:

Hi, Rance. Aluminum (aluminium) is strong, but it has been my

experience that threaded holes are easily stripped or deformed with
twisting motions. Steel would probably be best. As for the stability,
try using a shimming block against the inside vertical surface of the
tool, between it and the tool post. Good luck, Ron.

---- rancerupp <rupps@...> wrote:

Thanks Ron, and to Clint for posting the pics.

Ron, others, would you think that al. would be sufficient for

this or

does it have to be steel? The toolpost that comes with the 8x12

seems

huge. I would think that an alum. one of the same dimensions

would be

fine.

Also Ron, did you have any problems with the mounted tool bit
twisting while using your set screw configuration? Clint had
expressed concern of rigidity.

Rance


--- In 7x12minilathe@..., "Ronald Durbin"
<trainguy_347@> wrote:

I have done this with a smaller post, except that
I used set screws (or grub screws, as our British brothers and

sisters

call them) comming up from the bottom. To adjust, just undo the
retaining nut on top, lift up the post, back off the top screw
slightly, engage (run further in) the bottom screw tightly, and
replace the post as per normal. This sometimes take a few

tries,

but

once the height is achieved, all is well. Great drawings, by

the

way!.

Ron.

Well dooooooooh! 8) I have a lathe now. What was I thinking. I'm
gonna have to change my mindset. I could easily make my own steel
inserts now, right? :D That's one of the reasons I got this thing, so
I could make bits here and there when I need one and not have to run
to the h/w store or across town.


--- In 7x12minilathe@..., "rancerupp" <rupps@...> wrote:

Thanks Ron. So how about using threaded inserts in an aluminum

block?

First downside I see with an insert it creates an additional place
for possible lost rigidity. I've seen Pem Nuts for 6-32 screws in
1/16" alum. pate. Has anyone seen similar for 3/16 or 1/4 inch

bolts?

T-Nuts come to mind, but those are for wood. If the threads are the
only forseeable problem, then I'd prefer to use alum.

As for rigidity, my toolpost is 2 3/4 square and 1 5/8 high. Top

lip

is a bit over 1/2, the middle slot is about 3/4, the bottom lip is

a

bit over 1/4. The middle slot is about 1/2 in from the outer edge.
With that, the shortest threaded insert would be for the bottom
(1/4").

Good point about shimming the sides. I have some ideas on that but
I'll wait before introducing those.

Anyone know of sources for threaded steel inserts? Thanks.

Rance


--- In 7x12minilathe@..., <trainguy_347@> wrote:

Hi, Rance. Aluminum (aluminium) is strong, but it has been my

experience that threaded holes are easily stripped or deformed with
twisting motions. Steel would probably be best. As for the

stability,

try using a shimming block against the inside vertical surface of

the

tool, between it and the tool post. Good luck, Ron.

---- rancerupp <rupps@> wrote:

Thanks Ron, and to Clint for posting the pics.

Ron, others, would you think that al. would be sufficient for

this or

does it have to be steel? The toolpost that comes with the 8x12

seems

huge. I would think that an alum. one of the same dimensions

would be

fine.

Also Ron, did you have any problems with the mounted tool bit
twisting while using your set screw configuration? Clint had
expressed concern of rigidity.

Rance


--- In 7x12minilathe@..., "Ronald Durbin"
<trainguy_347@> wrote:

I have done this with a smaller post, except that
I used set screws (or grub screws, as our British brothers

and

sisters

call them) comming up from the bottom. To adjust, just undo

the

retaining nut on top, lift up the post, back off the top

screw

slightly, engage (run further in) the bottom screw tightly,

and

replace the post as per normal. This sometimes take a few

tries,

but

once the height is achieved, all is well. Great drawings, by

the

way!.

Ron.

Rance, as a machinist, even a hobby machinist, you do start to look at things differently. It sometimes is a curse. When my eyesight was better, I saw every crooked picture on a wall, and noticed every miter joint that didn't line up. With age, I don't notice as much, but still like to believe that I can think out problems and come up with creative solutions. Today, I tried my hand at making a miniature cannon, with plans as a guideline, but not using them for accurate machining. I just wanted to get my skills back, and it was fun figuing out how to replace a section that I accidently cut off! Good luck, Ron.
Keep makin' chips!!


---- rancerupp <rupps@...> wrote:

A common method of making strong threaded holes in aluminum is with
Helicoils. If you're not familiar with them, they're spring looking
objects, wound from trapezoidal wire, usually stainless steel. In
practice, the hole is tapped oversize with a special "STI" (Screw
Thread Insert) tap, the insert is screwed in, its driving tang is
broken off & the job is done. In addition to being common in the
aviation industry they're also widely used to repair damaged threaded
holes.



Roy

--- In 7x12minilathe@..., "rancerupp" <rupps@...> wrote:

Thanks Ron. So how about using threaded inserts in an aluminum

block?

First downside I see with an insert it creates an additional place
for possible lost rigidity. I've seen Pem Nuts for 6-32 screws in
1/16" alum. pate. Has anyone seen similar for 3/16 or 1/4 inch

bolts?

T-Nuts come to mind, but those are for wood. If the threads are the
only forseeable problem, then I'd prefer to use alum.

As for rigidity, my toolpost is 2 3/4 square and 1 5/8 high. Top

lip

is a bit over 1/2, the middle slot is about 3/4, the bottom lip is

a

bit over 1/4. The middle slot is about 1/2 in from the outer edge.
With that, the shortest threaded insert would be for the bottom
(1/4").

Good point about shimming the sides. I have some ideas on that but
I'll wait before introducing those.

Anyone know of sources for threaded steel inserts? Thanks.

Rance


--- In 7x12minilathe@..., <trainguy_347@> wrote:

Hi, Rance. Aluminum (aluminium) is strong, but it has been my

experience that threaded holes are easily stripped or deformed with
twisting motions. Steel would probably be best. As for the

stability,

try using a shimming block against the inside vertical surface of

the

tool, between it and the tool post. Good luck, Ron.

---- rancerupp <rupps@> wrote:

Thanks Ron, and to Clint for posting the pics.

Ron, others, would you think that al. would be sufficient for

this or

does it have to be steel? The toolpost that comes with the 8x12

seems

huge. I would think that an alum. one of the same dimensions

would be

fine.

Also Ron, did you have any problems with the mounted tool bit
twisting while using your set screw configuration? Clint had
expressed concern of rigidity.

Rance


--- In 7x12minilathe@..., "Ronald Durbin"
<trainguy_347@> wrote:

I have done this with a smaller post, except that
I used set screws (or grub screws, as our British brothers

and

sisters

call them) comming up from the bottom. To adjust, just undo

the

retaining nut on top, lift up the post, back off the top

screw

slightly, engage (run further in) the bottom screw tightly,

and

replace the post as per normal. This sometimes take a few

tries,

but

once the height is achieved, all is well. Great drawings, by

the

way!.

Ron.

Hi, Roy. That is a good point. I had thought of recommending Helicoils, but the expense of the special taps and insertion tools seemed somewhat prohibitive at our level. Used many a Helicoil myself to get a million dollar light bulb-making machine going again. Not as impressive as saving a 10 million dollar jet fighter, but they do work great, if you have enough depth to use them. I have cut them off to use in shallower holes, but I was getting paid to do that, not playing on my own time. They are a wonderful tool to have in reserve when just nothing else will work.
Rance, don't be afraid of using steel for making things; it machines nicely, and is pretty darn common in junk and salvage yards. Don't be seduced by stainless steel for making parts, unless really needed. It sounds superior, but for a novice it can be a nightmare, mainly because of it's "stringy" toughness when machining. Wait a bit until you see how other materials cut, then practice on some stainless to see the difference. All part of the learning curve, Babe!
BTW, remember to use coarser threads in soft materials, and finer threads for harder ones. For example, 1/4-20 for aluminum, 1/4-28 for mild steel. That's why the different thread sizes are there, not just for marketing purposes, as it sometimes seems.
Which brings up another point: when did hardware store like Sears stop selling fine thread fasteners? It seems like everything is now the coarse thread (NC as opposed to NF). At least thats the way it is at my local Sears.
Ron.
---- roylowenthal <roylowenthal@...> wrote:

Personal feeling is that they're nifty enough to be worth the price:-
) Locally, most auto parts stores have single size Helicoil kits in
the 1/4" to 1/2" range (& corresponding metric sizes) for a fairly
reasonable price. For the smaller sizes, you still have to go to an
industrial distributor. FWIW, the aviation industry routinely uses
fine threads for everything to maximize fastener strength (greater
root diameter.)

A few years ago, Sears tried some dedicated hardware stores - nifty
places, apparently didn't sell enough to stay open. Locally, the
only reliable retail source of NF stuff is the "Do It Best" hardware
store with the aisle filled with drawers of hardware assortments.
Mercifully, the industrial hardware place actively encourages retail
sales; unfortunately they're halfway across the next town over.

Roy

--- In 7x12minilathe@..., <trainguy_347@...> wrote:

Hi, Roy. That is a good point. I had thought of recommending

Helicoils, but the expense of the special taps and insertion tools
seemed somewhat prohibitive at our level. Used many a Helicoil myself
to get a million dollar light bulb-making machine going again. Not as
impressive as saving a 10 million dollar jet fighter, but they do
work great, if you have enough depth to use them. I have cut them off
to use in shallower holes, but I was getting paid to do that, not
playing on my own time. They are a wonderful tool to have in reserve
when just nothing else will work.

Rance, don't be afraid of using steel for making things; it

machines nicely, and is pretty darn common in junk and salvage yards.
Don't be seduced by stainless steel for making parts, unless really
needed. It sounds superior, but for a novice it can be a nightmare,
mainly because of it's "stringy" toughness when machining. Wait a bit
until you see how other materials cut, then practice on some
stainless to see the difference. All part of the learning curve,
Babe!

BTW, remember to use coarser threads in soft materials, and finer

threads for harder ones. For example, 1/4-20 for aluminum, 1/4-28 for
mild steel. That's why the different thread sizes are there, not just
for marketing purposes, as it sometimes seems.

Which brings up another point: when did hardware store like Sears

stop selling fine thread fasteners? It seems like everything is now
the coarse thread (NC as opposed to NF). At least thats the way it is
at my local Sears.

Ron.
---- roylowenthal <roylowenthal@...> wrote:

A common method of making strong threaded holes in aluminum is

with

Helicoils. If you're not familiar with them, they're spring

looking

objects, wound from trapezoidal wire, usually stainless steel.

In

practice, the hole is tapped oversize with a special "STI" (Screw
Thread Insert) tap, the insert is screwed in, its driving tang is
broken off & the job is done. In addition to being common in the
aviation industry they're also widely used to repair damaged

threaded

holes.



Roy

Take a look at Vicki Ford's site through the link on www.mini-lathe.com.
She made two very nice QCTP's from Aluminium, both clamp and piston trpe using steel insert for the threads

gerry
Leeds UK

From: "rancerupp" <rupps@...>
Reply-To: 7x12minilathe@...
To: 7x12minilathe@...
Subject: [7x12minilathe] Re: Shim Screw Tool Post (SSTP)
Date: Sat, 31 Mar 2007 19:32:53 -0000

Thanks Ron. So how about using threaded inserts in an aluminum block?
First downside I see with an insert it creates an additional place
for possible lost rigidity. I've seen Pem Nuts for 6-32 screws in
1/16" alum. pate. Has anyone seen similar for 3/16 or 1/4 inch bolts?
T-Nuts come to mind, but those are for wood. If the threads are the
only forseeable problem, then I'd prefer to use alum.

As for rigidity, my toolpost is 2 3/4 square and 1 5/8 high. Top lip
is a bit over 1/2, the middle slot is about 3/4, the bottom lip is a
bit over 1/4. The middle slot is about 1/2 in from the outer edge.
With that, the shortest threaded insert would be for the bottom
(1/4").

Good point about shimming the sides. I have some ideas on that but
I'll wait before introducing those.

Anyone know of sources for threaded steel inserts? Thanks.

Rance


--- In 7x12minilathe@..., <trainguy_347@...> wrote:

Hi, Rance. Aluminum (aluminium) is strong, but it has been my

experience that threaded holes are easily stripped or deformed with
twisting motions. Steel would probably be best. As for the stability,
try using a shimming block against the inside vertical surface of the
tool, between it and the tool post. Good luck, Ron.

---- rancerupp <rupps@...> wrote:

Thanks Ron, and to Clint for posting the pics.

Ron, others, would you think that al. would be sufficient for

this or

does it have to be steel? The toolpost that comes with the 8x12

seems

huge. I would think that an alum. one of the same dimensions

would be

fine.

Also Ron, did you have any problems with the mounted tool bit
twisting while using your set screw configuration? Clint had
expressed concern of rigidity.

Rance


--- In 7x12minilathe@..., "Ronald Durbin"
<trainguy_347@> wrote:

I have done this with a smaller post, except that
I used set screws (or grub screws, as our British brothers and

sisters

call them) comming up from the bottom. To adjust, just undo the
retaining nut on top, lift up the post, back off the top screw
slightly, engage (run further in) the bottom screw tightly, and
replace the post as per normal. This sometimes take a few

tries,

but

once the height is achieved, all is well. Great drawings, by

the

way!.

Ron.

_________________________________________________________________
Match.com - Click Here To Find Singles In Your Area Today!