Re: Control Board Ratings
G'day Ed.
The control boards have a current limit adjustment which sets the
maximum current which can be fed to the motor. I only have circuit
details of the board in my lathe (As available off the board
manufacturer's web site.) so I don't know how the current limit
function is achieved on other boards. I just know it is there from
articles about adjusting the minimum speed an earlier lathes.
Current limiting is necessary to prevent overheating of the motors,
inadvertent fuse blowing and demagnetisation of the field magnets.
As I said the board on my lathe is good for 6 amps (12 amps with
additional heatsink) so it is able to supply the motor without
limitation.
I am hoping Jim RabidWolfe can give some insight into what other types
of board can do.
Some of the boards do use pulse width modulation much as I imagine is
used by the stepper motor drive circuit. I many ways this is a more
modern technique than SCR phase control as used on my board. Your
stepper motor pulses would have a comparatively high voltage and short
duration to get the speed of response.
One good turn deserves another.
Regards,
Ian
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Ian - So what does this mean - the board automatically limits current
to what it's set at? Is this similar to a 'chopper' circuit? The
control board I built for my CNC router allows me to set the current
for my stepper motors and run them at much higher voltages than
they're rated for.
Ed
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Re: Control Board Ratings
BTW I fitted the "correct" Horsepower resitor to my control board
last night and now have adjusted it for 3.5 amps stall current. When
the stall load is applied the current rises to 4.5 amps then
immediately swings back to 3.5 amps. Ian - So what does this mean - the board automatically limits current to what it's set at? Is this similar to a 'chopper' circuit? The control board I built for my CNC router allows me to set the current for my stepper motors and run them at much higher voltages than they're rated for. Ed
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I wanted to let everyone know about three Flickr groups I've created:
Flickr has a number of advantages over the Yahoo photo page since it
has virtually unlimited storage & a very useful annotation feature
(roll your mouse over the photo at
to see what I mean). Photos can also be tagged so they can be
searched. For example, searching for minimill and beltdrive would find
the above photo and the others in the series.
The groups are public, so anyone can browse the photos, but you must
join the group to post photos to it. Not to mention, no more having to
login to Yahoo just to look at a photo!
Flickr is owned by Yahoo, the same username & password that you use to
login to Yahoo groups will work for it as well. I encourage everyone
to join whichever groups apply to you!
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You are right, A gun barrel is hard to drill. I would love to be able to buy a deep hole rig and the bits, but if I could afford that, I wouldn't need to ask questions. Not to mention, it would not fit in my upstairs spare bed-room turned machine shop. I am in the process of building a rifling machine, which will only ream and rifle. I am debating trying to build a tiny hook cutter, or to make a stepped rifling reamer. The reamer is a tad more complicated, but at this small size, probably a better choice than a tiny hook cutter. BTW are you a Lilja from the Lilja barrel folks? --- In 7x12minilathe@..., "Pete Lilja" <plilja@...> wrote:
A gun barrel is not an easy thing to drill accurately. Some rather
specialized machinery is utilized.
Granted yours is a short barrel but take a look around here for some
ideas as to how they're made:
Specifically look here:
It is my understanding that a gun drill is a special lathe with a
hollow drill (not a twist bit by any means) that floods the cutting edge with lots of oil for lubrication, cooling and chip removal.
There is an awful lot of info on rifles, shooting and some on barrel
making on the web site above. The barrel is rather critical in the performance of the gun. I wouldn't attempt one on a mini-lathe myself.
How do you plan to rifle the barrel?
----- Original Message -----
From: taurokm3
To: 7x12minilathe@...
Sent: Wednesday, April 11, 2007 5:00 PM
Subject: [7x12minilathe] Re: Deep Hole .218 x 8"
The material is 4140 Steel, and it will go in the chuck, it would go
through the spindle, but I have no way to clamp it to the face plate.
This is going to be a gun barrel. It is .770" diameter and 8
inches long (total), with a tip that is 1" x .950" I am thinking of
building some v notched clamps out of aluminum that would bolt to the
faceplate, with notches for the bolts so I can center the stock. It
has been suggested that I weld a standard bit to a length of drill rod
with a V and use that, I just don't know what kind of hole that would
give me.
Thanks
Doug
--- In 7x12minilathe@..., "John" <John@> wrote:
>
> Are you drilling this hole into material that can be held in the
lathe > chuck? Material dimensions and the material type would be helpful info. >
> The technique is straight forward (but tedious) if the material fits
> in the chuck. Best situation is if the material fits through the
> spindle, of course.
>
> John
>
>
>
> --- In 7x12minilathe@..., "taurokm3" <grimjack@> wrote:
> >
> > Any one have any thoughts on the best way to go about a deep hole
> > without buying a deep hole rig? I am currently experimenting with a > > home made drill, .175 x 11" shank with a .218 x 1" head, and I want to > > mill it to a flat on top and bottom, then sharpen it like a twist
> > drill. I know it will need cleared frequently, and a lot of lube.
> > BTW, I am using oil hardening drill rod for the bit. Any one have any > > other ideas?
> >
>
[Non-text portions of this message have been removed]
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CJ, go to Then click on Premium Content. You'll have to pay $4.95 (I think) and there you will find an excellent education on the knurling. I paid for unlimited access to the Premium Content because it is a wonder source of both instrucitons and projects. Also, the free portion of that Web site provides about the best education on the mini-lathe there is anywhere. --- In 7x12minilathe@..., "cjwires" <cjwarchitects@...> wrote:
hi, I am a new "enthusiast" to the mini machine world. Can anyone
point me to some basic info about how to use a knurling tool on the mini lathe? thanks, CJ
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See the 7x12 Files section, FAQ which has a basic overview in the section on Knurling. That may get you going, if not post back with specific questions. John --- In 7x12minilathe@..., "cjwires" <cjwarchitects@...> wrote:
hi, I am a new "enthusiast" to the mini machine world. Can anyone
point me to some basic info about how to use a knurling tool on the mini lathe? thanks, CJ
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I just got this email from Enco and thought I'd share it...
Ed
Hi Metalworking Professional,
Today through April 30th, get Free UPS Shipping* when you purchase $50
or more in merchandise from Enco.
Take advantage of this exclusive offer by entering WBARN7 in the promo
code box on the shopping cart page at use-enco.com, or mention the
code when you call 800-USE-ENCO and speak to a friendly sales
associate. Hurry, this offer expires Monday, April 30th, 2007, so act
today!
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G'day Jim, et al
Jim I look to your comments on the current capacities of the various
control boards used in the 7x lathes. I am posting on the group
because the outcome of the discussion effects others on the group.
For my lathe this is not a concern, the KB Electronics board fitted
has capacity for motors up to 1.0HP or can supply 9 amps. KB advised
me that my 400W (180Volt) motor with full load current of 2.2 amps
can have a current limit setting of 3.5 amps
HOWEVER, other control boards may not be so generaously rated and
some recent correspondence implies that the boards are limiting the
available current to the motors. In that the motors have an
overcurrent capacity of up to 2 times the full load current it seems
unlikely to me that the SCRs on FETs would be so minimally rated that
more than full load current can be supplied. (Making gibes
about "Chinese Horse Power" is not helpful).
BTW I fitted the "correct" Horsepower resitor to my control board
last night and now have adjusted it for 3.5 amps stall current. When
the stall load is applied the current rises to 4.5 amps then
immediately swings back to 3.5 amps.
One good turn deserves another.
Regards,
Ian
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Re: Database of past messages
G'day Patrice, et al. I have just looked ate the "Data Base" web site; it contains excellent material. Thanks for letting it be known. One good turn deserves another. Regards, Ian --- In 7x12minilathe@..., "borenson444" <strempe4@...> wrote:
Thanks all for the replies. I am glad to know that this could help.
Ian, the database (loose use of the term) is located on my personal
website for ease of use. Here is the addy:
It is HTML based for ease of use and downloading (Yahoo is great but
sadly a little lacking in this department ;-).
I'll wait for the ok from the owner of this group.
Thanks again
Patrice
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hi, I am a new "enthusiast" to the mini machine world. Can anyone point me to some basic
info about how to use a knurling tool on the mini lathe? thanks, CJ
|
Re: Database of past messages
Thanks all for the replies. I am glad to know that this could help.
Ian, the database (loose use of the term) is located on my personal
website for ease of use. Here is the addy:
It is HTML based for ease of use and downloading (Yahoo is great but
sadly a little lacking in this department ;-).
I'll wait for the ok from the owner of this group.
Thanks again
Patrice
|
The best description I've seen for accurately drilling a deep hole was posted by Peter S in the following thread: In case that link doesn't work, go here: And search for: Drilling a Long Straight Hole The post by PeterS on page 2 of the thread has the info. If you can't find it write to me via email and I'll send it. This approach will need to be adapted for the smaller hole you're drilling but this should be possible. I believe you could make and use D bits rather than purchase special reamers, a cost vs time tradeoff. John --- In 7x12minilathe@..., "taurokm3" <grimjack@...> wrote:
The material is 4140 Steel, and it will go in the chuck, it would go
through the spindle, but I have no way to clamp it to the face plate.
This is going to be a gun barrel. It is .770" diameter and 8
inches long (total), with a tip that is 1" x .950" I am thinking of
building some v notched clamps out of aluminum that would bolt to the
faceplate, with notches for the bolts so I can center the stock. It
has been suggested that I weld a standard bit to a length of drill rod
with a V and use that, I just don't know what kind of hole that would
give me.
Thanks
Doug
--- In 7x12minilathe@..., "John" <John@> wrote:
Are you drilling this hole into material that can be held in the lathe
chuck? Material dimensions and the material type would be helpful
info.
The technique is straight forward (but tedious) if the material fits
in the chuck. Best situation is if the material fits through the
spindle, of course.
John
--- In 7x12minilathe@..., "taurokm3" <grimjack@> wrote:
Any one have any thoughts on the best way to go about a deep hole
without buying a deep hole rig? I am currently experimenting with a
home made drill, .175 x 11" shank with a .218 x 1" head, and I
want to mill it to a flat on top and bottom, then sharpen it like a twist
drill. I know it will need cleared frequently, and a lot of
lube. BTW, I am using oil hardening drill rod for the bit. Any one
have any other ideas?
|
Somehow, I thought there was some significance to a hole that was just under .22! There's a bit of amateur barrel-making advice at yarchive.net/metal/barrel-drilling.html (Google "gun barrel boring" if that doesn't work). I once went round the BSA (Birmingham Small Arms) factory here in the UK, to see how their Martini action .22 target rifles were made. At the end of the barrel production line there was an old guy equipped with a couple of wooden blocks, a hammer and a convenient window. His job was to straighten the the things up after all the machining, and he did it well - my 1960's model still shoots better than I can. Andy taurokm3 <grimjack@...> wrote: The material is 4140 Steel, and it will go in the chuck, it would go through the spindle, but I have no way to clamp it to the face plate. This is going to be a gun barrel. It is .770" diameter and 8 inches long (total), with a tip that is 1" x .950" I am thinking of building some v notched clamps out of aluminum that would bolt to the faceplate, with notches for the bolts so I can center the stock. It has been suggested that I weld a standard bit to a length of drill rod with a V and use that, I just don't know what kind of hole that would give me. Thanks Doug --- In 7x12minilathe@..., "John" <John@...> wrote:
Are you drilling this hole into material that can be held in the lathe
chuck? Material dimensions and the material type would be helpful info.
The technique is straight forward (but tedious) if the material fits
in the chuck. Best situation is if the material fits through the
spindle, of course.
John
--- In 7x12minilathe@..., "taurokm3" <grimjack@> wrote:
Any one have any thoughts on the best way to go about a deep hole
without buying a deep hole rig? I am currently experimenting with a
home made drill, .175 x 11" shank with a .218 x 1" head, and I want to
mill it to a flat on top and bottom, then sharpen it like a twist
drill. I know it will need cleared frequently, and a lot of lube.
BTW, I am using oil hardening drill rod for the bit. Any one have any
other ideas?
--------------------------------- Yahoo! Mail is the world's favourite email. Don't settle for less, sign up for your freeaccount today.
|
A gun barrel is not an easy thing to drill accurately. Some rather specialized machinery is utilized.
Granted yours is a short barrel but take a look around here for some ideas as to how they're made:
Specifically look here:
It is my understanding that a gun drill is a special lathe with a hollow drill (not a twist bit by any means) that floods the cutting edge with lots of oil for lubrication, cooling and chip removal.
There is an awful lot of info on rifles, shooting and some on barrel making on the web site above. The barrel is rather critical in the performance of the gun. I wouldn't attempt one on a mini-lathe myself.
How do you plan to rifle the barrel?
toggle quoted message
Show quoted text
----- Original Message -----
From: taurokm3
To: 7x12minilathe@...
Sent: Wednesday, April 11, 2007 5:00 PM
Subject: [7x12minilathe] Re: Deep Hole .218 x 8"
The material is 4140 Steel, and it will go in the chuck, it would go
through the spindle, but I have no way to clamp it to the face plate.
This is going to be a gun barrel. It is .770" diameter and 8
inches long (total), with a tip that is 1" x .950" I am thinking of
building some v notched clamps out of aluminum that would bolt to the
faceplate, with notches for the bolts so I can center the stock. It
has been suggested that I weld a standard bit to a length of drill rod
with a V and use that, I just don't know what kind of hole that would
give me.
Thanks
Doug
--- In 7x12minilathe@..., "John" <John@...> wrote:
>
> Are you drilling this hole into material that can be held in the lathe
> chuck? Material dimensions and the material type would be helpful info.
>
> The technique is straight forward (but tedious) if the material fits
> in the chuck. Best situation is if the material fits through the
> spindle, of course.
>
> John
>
>
>
> --- In 7x12minilathe@..., "taurokm3" <grimjack@> wrote:
> >
> > Any one have any thoughts on the best way to go about a deep hole
> > without buying a deep hole rig? I am currently experimenting with a
> > home made drill, .175 x 11" shank with a .218 x 1" head, and I want to
> > mill it to a flat on top and bottom, then sharpen it like a twist
> > drill. I know it will need cleared frequently, and a lot of lube.
> > BTW, I am using oil hardening drill rod for the bit. Any one have any
> > other ideas?
> >
>
|
Re: Database of past messages
G'day Patrice Sounds a good idea. BUT ihave looked on the Southbend10k group and can't find the data base, where is it? One good turn deserves another. Regards, Ian --- In 7x12minilathe@..., "borenson444" <strempe4@...> wrote:
Hi
I am a Southbend lathe owner that created a database of past
messages for the Southbend groups a while ago. Since the resource seems to be
useful, I thought I'd maybe try and add one or two new ones. Metalwork being my hobby, this group seems interesting.
So I am asking permission from the administrator as well as from members.
I hope that this message will be moderated to see if it's ok as I
would not want to post something I am not supposed to.
Thanks for your time.
Patrice
|
The material is 4140 Steel, and it will go in the chuck, it would go
through the spindle, but I have no way to clamp it to the face plate.
This is going to be a gun barrel. It is .770" diameter and 8
inches long (total), with a tip that is 1" x .950" I am thinking of
building some v notched clamps out of aluminum that would bolt to the
faceplate, with notches for the bolts so I can center the stock. It
has been suggested that I weld a standard bit to a length of drill rod
with a V and use that, I just don't know what kind of hole that would
give me.
Thanks
Doug
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., "John" <John@...> wrote:
Are you drilling this hole into material that can be held in the lathe
chuck? Material dimensions and the material type would be helpful info.
The technique is straight forward (but tedious) if the material fits
in the chuck. Best situation is if the material fits through the
spindle, of course.
John
--- In 7x12minilathe@..., "taurokm3" <grimjack@> wrote:
Any one have any thoughts on the best way to go about a deep hole
without buying a deep hole rig? I am currently experimenting with a
home made drill, .175 x 11" shank with a .218 x 1" head, and I want to
mill it to a flat on top and bottom, then sharpen it like a twist
drill. I know it will need cleared frequently, and a lot of lube.
BTW, I am using oil hardening drill rod for the bit. Any one have any
other ideas?
|
Re: Database of past messages
Two thumbs up....
I think it would be a great addition to the group
cheers
toggle quoted message
Show quoted text
----- Original Message -----
From: borenson444
To: 7x12minilathe@...
Sent: Wednesday, April 11, 2007 12:28 PM
Subject: [7x12minilathe] Database of past messages
Hi
I am a Southbend lathe owner that created a database of past messages
for the Southbend groups a while ago. Since the resource seems to be
useful, I thought I'd maybe try and add one or two new ones. Metalwork
being my hobby, this group seems interesting.
So I am asking permission from the administrator as well as from members.
I hope that this message will be moderated to see if it's ok as I
would not want to post something I am not supposed to.
Thanks for your time.
Patrice
|
Re: Database of past messages
Patrice, Just a member here, but it sounds like a FINE idea considering the lack of Yahoo search capabilities. Jeff * REPLY SEPARATOR * On 4/11/2007 at 4:28 PM borenson444 wrote: Hi
I am a Southbend lathe owner that created a database of past messages
for the Southbend groups a while ago. Since the resource seems to be
useful, I thought I'd maybe try and add one or two new ones. Metalwork
being my hobby, this group seems interesting.
So I am asking permission from the administrator as well as from members.
I hope that this message will be moderated to see if it's ok as I
would not want to post something I am not supposed to.
Thanks for your time.
Patrice
- Demand Designs Analog/Digital Modelling & Goldsmithing jdemand@... -
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Database of past messages
Hi
I am a Southbend lathe owner that created a database of past messages
for the Southbend groups a while ago. Since the resource seems to be
useful, I thought I'd maybe try and add one or two new ones. Metalwork
being my hobby, this group seems interesting.
So I am asking permission from the administrator as well as from members.
I hope that this message will be moderated to see if it's ok as I
would not want to post something I am not supposed to.
Thanks for your time.
Patrice
|
--- In 7x12minilathe@..., Chris Eilbeck <chris@...> wrote:
On Mon, Apr 09, 2007 at 10:02:50PM -0000, Ian Foster wrote:
G'day Chris,
You need to taper the work piece to start with so do this by the
offset tail stock method. Follow by cutting your thread with the same
lathe settings. How do you firmly hold the work in the chuck when you've got the
tailstock centre offset?
You don't hold the work in the chuck. You turn between centers...mount a MT#3 center in the headstock and a MT#2 in the tailstock. Drive the work with a lathe dog. Charlie
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