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You have either misconnected something on the board, or cause a short. the most common cause of blowing fuses is either the bridge rectifier or the pot shorting out on the fuse-holder.

Check the connections and check for swarf on the board.

Begin there and let me know what you find - give me a yell if I can help.

Rabid
Uncle Rabid ( )
We Repair Electronic Speed Controllers
For Asian Mini Lathes and Mini Mills
"Just Crazy Enough To Get the Job Done"

Hi,
I just picked up a Cummins mini lathe and was wondering if there is
any resource out there that can tell me what speeds to run for diff
materials....I mostly play with Stainless Steel and not sure what speed
I should run my lathe at....Can anyone help??....Thanks, Kevin

On Saturday 31 March 2007, steam4ian wrote:

Thanks Vikki.
Good sleuthing. In that it fits the 7x14 it should fit the 7x12.

I'm not 100% sure that post fits the 7x stuff, but it seems a safe
assumption, I think :-).

That
tool post is really good because the bottom of the tool slot is
cupped to match the curved packer, the tool and packer is supported
over the full length of the packer. Somewhere I have seen a standard
tool post used with just the packer curved, the problem is that there
is only a thin line of contact with the bottom of the slot, not much
friction.

Does not sound good to me, I'd avoid anything like that unless I was
just doing balsa :).

At the price the Micro mark tool post could be hard to justify
against getting a QCTP, but it is worth thinking about.

I think that would be more rigid than the QCTP and if it were somewhat
less expensive having a few of them around might be worth it.

Take care, Vikki.
--
Victoria Welch, WV9K/7
“Anyone who describes Islam as a religion as intolerant encourages
violence,” --Turkish Foreign Ministry spokeswoman Tasnim Aslam

Thanks Vikki.
Good sleuthing. In that it fits the 7x14 it should fit the 7x12. That
tool post is really good because the bottom of the tool slot is cupped
to match the curved packer, the tool and packer is supported over the
full length of the packer. Somewhere I have seen a standard tool post
used with just the packer curved, the problem is that there is only a
thin line of contact with the bottom of the slot, not much friction.

At the price the Micro mark tool post could be hard to justify against
getting a QCTP, but it is worth thinking about.

One good turn deserves another.
Regards,
Ian

On Saturday 31 March 2007, steam4ian wrote:

G'day all.
Not wanting to rain on Rance's parade I have started a new topic.
Has anybody made, bought or used a rocking shim in the tool post?
The idea is that the bottom of the shim has a slight convexity and
the tool tip height can be finely adjusted by differential tightening
of the front and back screws. This replicates the adjustment provided
by the cup washer and half moon shim in the old lantern style tool
posts. Tip height adjustment does alter the tool rake but not enough
to be a problem

The one I was considering (still am :) is this one:



Seems like it should be solid enough. I like my QCTP, but it does flex
sometimes.

My experience was with the a single rocker post that held one bit on a
bigger machine, I liked it and it was easy to adjust.

I am concerned about the lateral tool rigidity, that is, the
likelyhood of the tool swinging back under load. Any comments.

Before I pick up some 50mm x 3mm flat and attack it with a file it
would be good to hear from others.

Can't speak from experience on that one I linked to, but it *looks*
good :). I need to ask them if that is for the 7x variety, at 5/8 max
for a bit, I am not sure.

Hope this helps!

Take care, Vikki (no connection to Micro-Mark).
--
Victoria Welch, WV9K/7
"I'm anti-war! Trouble is, the enemy isn't." -- Unknown

G'day all.
Not wanting to rain on Rance's parade I have started a new topic.
Has anybody made, bought or used a rocking shim in the tool post?
The idea is that the bottom of the shim has a slight convexity and the
tool tip height can be finely adjusted by differential tightening of
the front and back screws. This replicates the adjustment provided by
the cup washer and half moon shim in the old lantern style tool posts.
Tip height adjustment does alter the tool rake but not enough to be a
problem

I am concerned about the lateral tool rigidity, that is, the likelyhood
of the tool swinging back under load. Any comments.

Before I pick up some 50mm x 3mm flat and attack it with a file it
would be good to hear from others.

One good turn deserves another.
Regards,
Ian

The other day I put a dial indicator in a spare toolholder for my
QCTP, set it on centreline of my lathe, and left it on the shelf.

Tonight I had to do some stuff using the 4 jaw chuck, the job was
helped immensely by having the gauge set up already. (although it was
slowed by me not having the correct key for the chuck :{)

Stu G

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.

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:

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.

--- In 7x12minilathe@..., Michael Taglieri
<miket--nyc@...> wrote:

Another way I got the same result was to replace the clamping screw
that's there with a slightly longer one and modify the screw so I could
turn it from the threaded end to lock and unlock the tailstock. I filed
the end of the screw to a square and made a little wrench with a square
hole that I use to tighten and loosen the screw. Initially I was
wondering if that little square nubbin on the end would be strong enough
to torque the clamping screw down with, but I case-hardened it and it's
held up fine.

Mike Taglieri miket--nyc@...

Everyone has his reasons.
- Jean Renoir "The Rules of the Game"


On Wed, 28 Feb 2007 01:48:21 -0800 (PST) Malcolm Parker-Lisberg
<mparkerlisberg@...> writes:

To save all the trouble of all that machining, remove
the 5mm cap head screw that holds the tailstock bottom
plate to the top half that is used when adjusting the
offset. Drill 5mm through the top half, removing the
thread for the screw and make a sliding captive 5mm
threaded plate to take a 30 mm m5 cap head screw from
the inside of the top of the tailstock. Raise the
clamping nut with two 10mm washers so your tailstock
clamping spanner clears the new 5mm caphead offset
clamping screw. You can now adjust the position of the
tailstock without having to turn it over to adjust the
offset clamping screw.

Exactly what I've done ,the nut was made by milling two flats on steel
round bar drilling and threading and then slicing, the nut fits nicely
in the slot ,however as I have made a cam lock to the little machine
shop design ,the cap head does not interfere with any thing.

Geoff UK

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, 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:

If you are more interested in having the parts you describe instead of learning and playing with a lathe, you might do well to consider www.emachineshop.com. They have a small software program to download that allows you to make a sketch that gets quoted. You can experiment with a variety of manufacturing techniques, materials, quantities, tolerances, etc. to see what each option would cost. You can do all of this before you submit it to them for manufacture. You can also email them about other manufacturing options that you may not be aware of.
As others have said, the learning curve and cost of additional tooling are both fairly steep - worth it, mind you, if that is what you want to do, but otherwise maybe not the best approach.
Jim


nicipi <nicipi@...> wrote:
First, thanks for all your feedback Mike, John, Ian and Mike - you
guys have added a lot to my sense of what's involved in this
endeavor. I should at least clarify my tolerances.

The wall thickness can actually be anywhere between 16thou and
32thou, and every one that I make can be in that range (don't all
need to be identical); the only restriction here is that it still be
flarable. Also, the thickness should be relative to the 0.437" outer
diameter of the main part of the tube (the 0.437" can be plus/minus
5thou or maybe even 10thou). It is important that the
0.625" "outward rolled-like bead" be clean and rounded (a picture
would really help here - I have a photo and a schematic but don't
know how to share it with you guys). Otherwise, the surfaces don't
need to be perfect, so for example, as John points out, the inside of
the tube can be done with just drill/bore (if I'm using the right
wording).

What I first need to do is make sure I understand the procedural
options here. Each of you guys have added something unique to try,
and I've been reading your instructions over and over. What's just
now becoming a little clearer to me are things like what does the
tailstock do, what are the options for supporting the piece, what are
centers, etc., and most importantly, what is a mandrel and how is it
used (so that I can implement Mike's technique or variant thereof -
the mandrel seems to be a key here.) It certainly would be helpful
to see one of these machines up close and in action. I even looked
on youtube but only one video came up when I searched on "mini-lathe"
and it wasn't very enlightening.

Nicipi

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.

Thanks for advice, resistors ordered at cost of ?1 so if that is all that is wrong I shall have saved ?84 !! Thanks for your interest and support. Ian

On Friday 30 March 2007, born4something wrote:

Hi Vikki,

Don't feel too bad about that. A while back I made a similar blunder.

I knew cast iron had a rather high carbon content (~5% from memory)
but had never machined it before. So I mounted up my brand new face
plate to give it an initial facing cut - to true it. Wanting a
decent finish I kept up a goodly supply of WD40 aerosol. On a 160mm
disk it flicked everywhere. I had a nice line up the splash guard,
up the wall behind, fell short of the ceiling, down the driver's
door on my wife's car, across the floor and up my shirt. It took
some cleaning up.

So there are at least two of us who will remember not to lubricate
cast iron next time!

Comparatively I was lucky, all I had was a goopy pile in the tailstock
and some spatter on the drill press table!

Next time I will remember that. One has to be so careful about using
fluids around spinning things here and the less of it the better!

My face plate is still in the bag with the red goo, I'm very glad you
told me this story before I got to it :-)!

Take care, Vikki.
--
Victoria Welch, WV9K/7
The ultimate result of shielding men from the effects of folly is to
fill the world with fools. --Herbert Spencer, English Philosopher
(1820-1903)

On Friday 30 March 2007, rancerupp wrote:

TO help contain the dry dust, put a magnet in a baggie and locate it
near your cutting.

Duhhh, I clean up the lathe when I do magnetic stuff with a magnet in a
sandwich baggie turned inside out, just turn it rightside out, seal
and toss.

Why didn't I think of that here?

Sometimes we're slow :-). Thanks for the pointer / refresher /
reminder :-)!

Also, on the cam lock, I did put a washer under the quill lock lever to
move it back a bit from the cam lock lever. It was getting in the way
after all.

Thanks & take care, Vikki.
--
Victoria Welch, WV9K/7
Some people are like a Slinky ... not really good for anything, but you
still can't help but smile when you see one tumble down the
stairs. --Unknown

Hi Ian,

You referenced the 2 locknuts on the compound feed when you were
talking about the locking grub screw in the end of your leed screw
last week. I was mystified but figured I understood the leedscrew
bit so let the compound reference go through to the keeper. Now I
understand!

John



--- In 7x12minilathe@..., "steam4ian" <fosterscons@...>
wrote:

G'day all.

My machine may be a Real Bull, which may explain many of my posts!

More variations. The RBM machine (probably mine) has two lock nuts

on

the compound feed screw to provide adjustment of the bearing
backlash??? They bear on the dial and so effect that as well.
This also may explain why the 50 division dials I bought from LMS
don't fit. The internal diameter is 12mm whilst my feedscrew

shafts

are 10mm diameter.
The fix will not be difficult. For the cross slide I intend to

turn

up a bush, 10mm internal and 12mm external make a saw cut along

the

bush. I can cross drill and tap the dial 6mm (as per my existing
dial) and use a set screw to adjust the friction with the shaft.

For

the componud I can make a similar bush but with a collar at the
inboard end. The dial can also be cross drilled and also have a
recess for the collar of the bush bored out, the existing lock nut
can press against the outboard end of the bush.

Why the 50 div dials? because I work in metric and the Thou

divisions

are a pain, you have to calculate for evey adjustment.

Please join the game of "spot the difference."

One good turn deserves another.
Regards,
Ian

G'day all.

My machine may be a Real Bull, which may explain many of my posts!

More variations. The RBM machine (probably mine) has two lock nuts on
the compound feed screw to provide adjustment of the bearing
backlash??? They bear on the dial and so effect that as well.
This also may explain why the 50 division dials I bought from LMS
don't fit. The internal diameter is 12mm whilst my feedscrew shafts
are 10mm diameter.
The fix will not be difficult. For the cross slide I intend to turn
up a bush, 10mm internal and 12mm external make a saw cut along the
bush. I can cross drill and tap the dial 6mm (as per my existing
dial) and use a set screw to adjust the friction with the shaft. For
the componud I can make a similar bush but with a collar at the
inboard end. The dial can also be cross drilled and also have a
recess for the collar of the bush bored out, the existing lock nut
can press against the outboard end of the bush.

Why the 50 div dials? because I work in metric and the Thou divisions
are a pain, you have to calculate for evey adjustment.

Please join the game of "spot the difference."

One good turn deserves another.
Regards,
Ian