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Gregor, while I am no expert, generally there are three terms that
are used in heat treating - annealing, hardening , and tempering.
each metal has its own specifics but for example for o-1 ( aka oil
hardening ) its is annealed by heating it to a critical temperature (
for 0-1 when it is no longer magnetic ) then allowing to cool
slowly, often while packed in ashes. Once annealed it is at its
softest state and that is when it is shaped to rough form. The next
step is to again heat it to the critical temp then plunge it in the
appropriate coolant ( for o-1 warm oil) once it is quenched it is as
hard as it will get, but it is very brittle - to make it less brittle
it is tempered by heating it to a specific temp ( depending on how
hard you want it - the 350 -400 range is common for hand tools for
working wood). If you overheat it at this stage and make it too
soft, you can start again ( though I usually skip annealing and just
heat treat it, then after quenching, temper it again)

From another site I found this- The proceedure for 4140 is preheat to
1250 deg F then bring it up to 1550 deg F. Let it soak at temp for
probably 15-20 min and oil quench. Max hardness on 4140 is around 55
Rc I don't think you would want it that hard my sugestion would be to
draw it back to about 46-48 Rc.

Unless your part is very big you should have no problem getting it up
to 1550 with a MAPP torch, though I don't know how you would confirm
you reached that temp. Here is a site with a short description of
the temps for that metal

Family=Alloy+Steels&MetalName=4140

Very useful.
Thanks.
-JC

I made up a cheat sheet for setting the RPM on my minilathe for
various materials and diameters, and thought some folks here could use
it too.

Here it is in PDF:


And ODG:


The ODG file is editable with OpenOffice Draw, which is freely
available for just about any platform. You'll need this file to
change the knob RPM maps and SFM to suit your lathe & turning habits.
The PDF file is really just so you can see it without OpenOffice.

The table is a spreadsheet. To adjust it's values, right click on it
and select "EDIT". Then just change the SFM value and the other
fields will recompute. It rounds to 50 rpm unless sufficiently slow,
where it rounds to 25rpm. When you're done, just hit <ESC> and print it.

Since I have mostly HSS tooling, that's what the table is set for. I
figure it's easy enough to double the numbers mentally for carbide.
The RPMs were checked with a laser tachometer.

I hope someone else finds this useful!

-Paul Moir

Another question from a beginner. According to a basic book about home machinery it is possible to temper metal using a MAPP gas torch. I have tried this on a 4x1/2 punch made out of annealed 4140 with a standard MAPP gas torch suitable for plumbing work. I was unsuccessful because the punch did not get hot enough. Any suggestions? Thank you.
Gregor Stransky, San Antonio, Texas

--Hi Rance,

Not sure where your looking, but in the 2007 Grizzly catalog
(pg.614) they are $2.95 ea. I bought three, 1/32,1/16,1/8 with a 7/8
hole a few years ago when I first got my mini mill, during an
accessory "buying spree", just to have around. Shortly after that I
bought several end mills, taps, R-8 colletts, and more from someone
at a flea market selling tons of machine accessories that were used,
but well cared for, and no Asian stuff, all high quality prfessional
shop stuff, and I got a few 1/2" hole slitting saws with the bunch
of stuff, all for about $15! The biggest disappointment of all of it
was the "fits all" arbor from Grizzly. I don't use the saws alot,
but they're nice to have on hand. Certainly not a "must have" for
just starting out though. I cut alum. dry, steel needs cutting
fluid, w/ slow feed. Use some type of shield, they spray alot of
fluid!

Frank

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

Thanks Frank,

So is $9-$10 about the going price for :

Diameter (Inch): 2-1/2
Face Width (Inch): 1/16
Arbor Hole Size: 7/8
Material: HSS
Number of Teeth: 28
Type of Tooth: Plain Tooth

or should I look elsewhere since it prob. won't be the first
accessory I'll be wanting to use? Thanks.

Rance

PS: I think I'll just make my own arbor. Only need one size for

now.

--- In 7x12minilathe@..., "nyceacres200"
<nyceacres200@> wrote:

--- Hi Rance/Vikki,
For the occaisional times I need a slitting saw, I bought a few
from Grizzly a couple of years ago 2.5" dia. w/ a 7/8" hole, in
different thickness', and the "fits all" arbor. I found that the
saws don't run true with that arbor, although with care, they

work.

I also bought some smaller dia. (I think they're 1.75" dia) with

a

1/2" hole, at a flea market, for literaly pennies. The 1-1/4"

dia.

of the arbor leaves very little blade showing on the smaller

ones.

I

made a 7/8" arbor from alum. round stock, and a 1/2" arbor from

3/4"

round steel rod. They work much better,the saws run true, and

are

easier to use. And easy to make. The 3/4" rod arbor for the

smaller

saws leaves more cutting room. The diameter and thickness of the
saws depend on your needs. So far these few sizes have worked

for

me. If blanks are available, making your own is even easier.

Frank

G'donya John!

Ian
--- In 7x12minilathe@..., "born4something" <ajs@...>
wrote:

Hi Ian,

See my responses interspersed.


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

G'day John.
Firstly, I am not retired and out of it, I have my own engineering
consulting business of which I am both director and an enployee,

it

supports my other activities.

We do have a lot in common. That's my situation too. I haven't had

much

call for OH&S awareness thrust at me in this role. Pre 2003 I was

middle

managing in the public sector so awareness and compliance was really
pushed. If you go through the current competency based national
qualification scheme for any trade you'll get to do the OH&S ticket

and

learn all about it. I did a data cabling cert a while back and had

to do

it. My prior quals assumed it but when I wanted to add another

ticket I

got caught up in it. Similarly, a friend with a solar heating /

plumbing

company and a dozen employees gets tangled in it. Largely once you

get

involved with the construction industry at a hands on / employer

level.

My own company has only one employee (manager, secretary, director,

tea

maker - me) mostly doing design work so I haven't needed to worry

much.

Do you have other employees?

My thoughts still stand with respect to the home machinist. If the
machine is used by your employees then application of a guard or

some

similar "engineering" measure is esential. But, the ACTUAL hazard
must be identifed. It is pointless guarding the chuck and leaving

a

rotating workpiece exposed. The hazad of the key being flung out

is

real but the guard is not necessarilly the solution. As an
alternative the key could be set in a holder that de-energises the
lathe when the key is not in the holder.

Agreed. But shhh... Don't mention the rotating work as well!
Interestingly, my machine was delivered with a light spring slipped

over

the chuck key. It was just strong enough to eject the key from the

chuck

if you weren't constantly holding it in. You could not let go when

you

regripped the key while adjusting the chuck without having to fetch

the

key back out of the chip tray!

The chuck guard is grandma engineering, reaction not application.
Eventually we could have to fully enclose the lathe like a CNC
machine.

Only reason we don't is historical precedence. The modern automobile
could not be launched today unless fully computerised driving and

crash

avoidance were developed first. What's this human in control?! And

then

there's the hammer, chainsaw, ...

Did Sieg stuff up or those who ordered the machines from them?

Since others in various countries have reported the same 6" figure

on

the 7x12 machines I doubt it was just my distributor. It's looking
pretty universal.

If the chuck guard is to be retained you either put up with the
reduced swing or change the mounting of the guard as you

suggested.

Few users of the lathe will be swinging the full 7 inches but
interference with the standard faceplate is a different matter.

Not having a full 7" didn't really worry me either. But I was mighty
cheesed when I bought their faceplate and had to remove the supplied
guard to fit it. After trueing the faceplate up I haven't used it

again.

I've made do with the 4-jaw a few times where the faceplate would

have

been the more logical choice. <G>

I don't know what it is about these lathes but they bring out a

rash

of complaints in some people. For me, I am just happy to have a
lathe; even more so one that is not such a sacred cow that I am
unwilling to tamper with it. It is amazing, if you stuff a part

up it

is just an email to someone like LMS and you are underway again at
comparatively little cost, few other lathes offer that

opportunity.

Got that off my chest!

I hearty hear, hear! I'm in no doubt on that one. My budget was $1k

and

that's sorta where I ended up with some accessories. Ok, I cribbed

a few

more accessories than that. But no, I'm not complaining overall. I

can

live with having to lap my gibs, align the tailstock, clean up the

odd

burred thread, fitting an apron swarf guard, etc. But some things

are

harder to rectify properly. That guard is one of them. Yeah, I had

to

get that off my chest too!

And yes, I love the spares situation too. I have and old ex Water

Board

aluminium runabout. Before I owned it I doubt it ever saw a boat

ramp.

Just a rocky hillside into a dam. It was a workboat and had a hard

life.

Very little paint left after 30 years. Gee I love that Ugly

Duckling. I

never worry about fenders to keep it from being scratched on

barnacles.

Or people scratching the paint with shoes. It's really laid back and
comfortable. I'm feeling that way about my 7x12 after 4 months due
largely to LMS being on standby!

One good turn deserves another.
Regards to all,
Ian

Keep on turnin',
John

FYI, check out the GrizHFMiniMill mailing list. I find it much more
useful then the minimill list.

Some, Gregor - other than price, it's not much. It's a good mill if you're
planning on doing only very small parts. Even the "Mini" mill is definitely
NOT a Bridgeport.

You have to remember the intent of the designers on these machines and keep
their limitations in mind.

Rabid
Uncle Rabid ( )
We Repair Electronic Speed Controllers
For Asian Mini Lathes and Mini Mills
"Just Crazy Enough To Get the Job Done"
(Join Rabid's Lathe/Mill Controller/Mod's List!)
(Also visit BarStockEngines - join us in building without Castings!)

Hi,
Does any of you have any experiance with the CJ0618 mini lathe?
I'll appretiate getting any piece of info.

Itamar.

Gregor
The Mini Mill sometimes proves to be a bit cramped for space and
travel. The Micro Mill, which is even smaller, would be very limiting
in what you would be able to do with it. I'd probably nudge you toward
the larger Mini Mill just to keep the predictable curses from scaring
small children. A bit more expense, but it's also a quite bit more
machine.

Steve

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

Hi:
I just joined the group. I only recently became interested in home shop
machinery and have been doing some lathe work on my 7x12 Cummins. I

plan to

buy a mill in the near future. Does anybody have any experience with

the

HarborFreight Micro Mill/Drill that sells for $299? I already posted

the

same question to the mini-mill group, but received only a few

responses.

Thank you.
Gregor Stransky, San Antonio, Texas

I see from ArcEuroTrade's website that they have 7x14s on offer just
now. "5 machines only" it says. Also says "Due to overstocking", which
seems a bit contradictory.
Andy

Greger

I have owned the mini mill but not the micro mill. depends on what you are interested in as far as projects.
personally, I think the mini is as small as I would ever go, actually I ended up with a Bridgeport style mill because I was so limited on the mini.

Cumminstool.com has the mini mill at the best deal I know of right now, dont know for sure if they carry the micro mill?
Clint
.


gregorstransky@... wrote:

Hi Ian,

See my responses interspersed.


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

G'day John.
Firstly, I am not retired and out of it, I have my own engineering
consulting business of which I am both director and an enployee, it
supports my other activities.

We do have a lot in common. That's my situation too. I haven't had much
call for OH&S awareness thrust at me in this role. Pre 2003 I was middle
managing in the public sector so awareness and compliance was really
pushed. If you go through the current competency based national
qualification scheme for any trade you'll get to do the OH&S ticket and
learn all about it. I did a data cabling cert a while back and had to do
it. My prior quals assumed it but when I wanted to add another ticket I
got caught up in it. Similarly, a friend with a solar heating / plumbing
company and a dozen employees gets tangled in it. Largely once you get
involved with the construction industry at a hands on / employer level.
My own company has only one employee (manager, secretary, director, tea
maker - me) mostly doing design work so I haven't needed to worry much.
Do you have other employees?

My thoughts still stand with respect to the home machinist. If the
machine is used by your employees then application of a guard or some
similar "engineering" measure is esential. But, the ACTUAL hazard
must be identifed. It is pointless guarding the chuck and leaving a
rotating workpiece exposed. The hazad of the key being flung out is
real but the guard is not necessarilly the solution. As an
alternative the key could be set in a holder that de-energises the
lathe when the key is not in the holder.

Agreed. But shhh... Don't mention the rotating work as well!
Interestingly, my machine was delivered with a light spring slipped over
the chuck key. It was just strong enough to eject the key from the chuck
if you weren't constantly holding it in. You could not let go when you
regripped the key while adjusting the chuck without having to fetch the
key back out of the chip tray!

The chuck guard is grandma engineering, reaction not application.
Eventually we could have to fully enclose the lathe like a CNC
machine.

Only reason we don't is historical precedence. The modern automobile
could not be launched today unless fully computerised driving and crash
avoidance were developed first. What's this human in control?! And then
there's the hammer, chainsaw, ...

Did Sieg stuff up or those who ordered the machines from them?

Since others in various countries have reported the same 6" figure on
the 7x12 machines I doubt it was just my distributor. It's looking
pretty universal.

If the chuck guard is to be retained you either put up with the
reduced swing or change the mounting of the guard as you suggested.
Few users of the lathe will be swinging the full 7 inches but
interference with the standard faceplate is a different matter.

Not having a full 7" didn't really worry me either. But I was mighty
cheesed when I bought their faceplate and had to remove the supplied
guard to fit it. After trueing the faceplate up I haven't used it again.
I've made do with the 4-jaw a few times where the faceplate would have
been the more logical choice. <G>

I don't know what it is about these lathes but they bring out a rash
of complaints in some people. For me, I am just happy to have a
lathe; even more so one that is not such a sacred cow that I am
unwilling to tamper with it. It is amazing, if you stuff a part up it
is just an email to someone like LMS and you are underway again at
comparatively little cost, few other lathes offer that opportunity.

Got that off my chest!

I hearty hear, hear! I'm in no doubt on that one. My budget was $1k and
that's sorta where I ended up with some accessories. Ok, I cribbed a few
more accessories than that. But no, I'm not complaining overall. I can
live with having to lap my gibs, align the tailstock, clean up the odd
burred thread, fitting an apron swarf guard, etc. But some things are
harder to rectify properly. That guard is one of them. Yeah, I had to
get that off my chest too!

And yes, I love the spares situation too. I have and old ex Water Board
aluminium runabout. Before I owned it I doubt it ever saw a boat ramp.
Just a rocky hillside into a dam. It was a workboat and had a hard life.
Very little paint left after 30 years. Gee I love that Ugly Duckling. I
never worry about fenders to keep it from being scratched on barnacles.
Or people scratching the paint with shoes. It's really laid back and
comfortable. I'm feeling that way about my 7x12 after 4 months due
largely to LMS being on standby!

One good turn deserves another.
Regards to all,
Ian

Keep on turnin',
John

Gregor:

There's a bit of information regarding the HF mini and micro mills
over on the C-O Lathe group, listing the pluses, limitations, etc.
Come on over and have a look...



Type micro mill into the search parameter, and it'll pop up the whole
bevy of related posts...

Cheers,
Mark
=======


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

Hi:
I just joined the group. I only recently became interested in home shop
machinery and have been doing some lathe work on my 7x12 Cummins. I

plan to

buy a mill in the near future. Does anybody have any experience with

the

HarborFreight Micro Mill/Drill that sells for $299? I already posted

the

same question to the mini-mill group, but received only a few

responses.

Thank you.
Gregor Stransky, San Antonio, Texas

G'day John.
Firstly, I am not retired and out of it, I have my own engineering
consulting business of which I am both director and an enployee, it
supports my other activities.
My thoughts still stand with respect to the home machinist. If the
machine is used by your employees then application of a guard or some
similar "engineering" measure is esential. But, the ACTUAL hazard
must be identifed. It is pointless guarding the chuck and leaving a
rotating workpiece exposed. The hazad of the key being flung out is
real but the guard is not necessarilly the solution. As an
alternative the key could be set in a holder that de-energises the
lathe when the key is not in the holder.

The chuck guard is grandma engineering, reaction not application.
Eventually we could have to fully enclose the lathe like a CNC
machine.

Did Sieg stuff up or those who ordered the machines from them?

If the chuck guard is to be retained you either put up with the
reduced swing or change the mounting of the guard as you suggested.
Few users of the lathe will be swinging the full 7 inches but
interference with the standard faceplate is a different matter.

I don't know what it is about these lathes but they bring out a rash
of complaints in some people. For me, I am just happy to have a
lathe; even more so one that is not such a sacred cow that I am
unwilling to tamper with it. It is amazing, if you stuff a part up it
is just an email to someone like LMS and you are underway again at
comparatively little cost, few other lathes offer that opportunity.

Got that off my chest!

One good turn deserves another.
Regards to all,
Ian

Over the last decade or two there's been a bureaucrat takeover of

industrial safety. I'm sure the drive comes from insurers covering
compensation liability. > They'd claim consultation. However, the

safety legislation enforces a

structure aimed at unskilled workers. Not surprising. The structure

was

devised by unskilled administrators forming committees advising
bureaucrats. Maybe I'd best get off my hobby horse at this point and
quote you the legislated hierarchy of controls as used in Australia

(and

elsewhere).

The Hierarchy of Controls = preferred order of control measures

for OHS

risks.

1. Elimination - controlling the hazard at source. 2.
Substitution - eg. replacing one substance or activity with a less
hazardous one. 3. Engineering - eg. installing guards on

machinery

4. Administration - policies and procedures for safe work

practices

5. Personal Protective Equipment - eg respirators, ear plugs.

Training is seen as a means to help this all work. However, it is

not a

substitute for using the above list.

Hi:
I just joined the group. I only recently became interested in home shop machinery and have been doing some lathe work on my 7x12 Cummins. I plan to
buy a mill in the near future. Does anybody have any experience with the HarborFreight Micro Mill/Drill that sells for $299? I already posted the same question to the mini-mill group, but received only a few responses. Thank you.
Gregor Stransky, San Antonio, Texas

Thanks Frank,

So is $9-$10 about the going price for :

Diameter (Inch): 2-1/2
Face Width (Inch): 1/16
Arbor Hole Size: 7/8
Material: HSS
Number of Teeth: 28
Type of Tooth: Plain Tooth

or should I look elsewhere since it prob. won't be the first
accessory I'll be wanting to use? Thanks.

Rance

PS: I think I'll just make my own arbor. Only need one size for now.


--- In 7x12minilathe@..., "nyceacres200"
<nyceacres200@...> wrote:

--- Hi Rance/Vikki,
For the occaisional times I need a slitting saw, I bought a few
from Grizzly a couple of years ago 2.5" dia. w/ a 7/8" hole, in
different thickness', and the "fits all" arbor. I found that the
saws don't run true with that arbor, although with care, they work.
I also bought some smaller dia. (I think they're 1.75" dia) with a
1/2" hole, at a flea market, for literaly pennies. The 1-1/4" dia.
of the arbor leaves very little blade showing on the smaller ones.

I

made a 7/8" arbor from alum. round stock, and a 1/2" arbor from

3/4"

round steel rod. They work much better,the saws run true, and are
easier to use. And easy to make. The 3/4" rod arbor for the smaller
saws leaves more cutting room. The diameter and thickness of the
saws depend on your needs. So far these few sizes have worked for
me. If blanks are available, making your own is even easier.

Frank

Most email clients seem to gracefully handle punctuation at the end of
URLs, but I'll watch more closely in the future.

Mike

I just clicked on it as posted - it looks like the period got included
as part of the hyperlink. It works without it. Thanks.

Hmm... Did you copy the period at the end of the sentence? The link
works fine for me. It's the link to their reference section, rather
then directly to the cutting speeds page, though.