Re: Taper - I think I have a problem?!
No twist in my bed but the headstock was off by 0.015 in 8" when I got it.
After aligning using "Rollie's Dad's Method", my DTI (0.0005) doesn't twitch over the same distance. I can turn a 3" length and have it come out with no taper as measured with a good (? Starret) micrometer.
Aaron
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Show quoted text
----- Original Message -----
From: Ed Boysun
To: 7x12minilathe@...
Sent: Saturday, March 24, 2007 8:54 AM
Subject: [7x12minilathe] Re: Taper - I think I have a problem?!
Guys that should know, tell me that a lathe bed has almost no resistance
to twist. You need to beg, borrow, or steal a machinist's precision
level and check the bed, both at the headstock and near the tailstock to
make sure that the level reads exactly the same in both places. If your
bench is solid, you may need to add shims beneath the legs on the lathe,
then clamp it back to the bench. If your table is not completely rigid,
you can adjust the feet of the table to impart some twist to the table,
and thus to the lathe bed. It surprised me; just how much a small shim
will de-twist the bed. A twisted bed will exhibit exactly the symptoms
you describe.
Ed B
--- In 7x12minilathe@..., "wrlabs" <wrlabs@...> wrote:
>
> Hi Folks,
>
> If I can poll the collective wisdom on this I'd appreciate it.
>
> I'm not sure I have a problem, but I think so.
>
> Turning down a rod I get a 0.015" difference over 5.5", please see:
>
>
>
> I would guess that would turn into 0.030" over 11"?
>
> If I turn a cone in the chuck and pull up the tailstock, they appear
> to match up as near as I can tell.
>
> My failed laser edge finder drew a circle around the the tailstock
> center that looked centered to me.
>
> I get this just turning a reasonably robust rod just clamped in the
> chuck too (measurable difference between ends, forget what the value
> is now).
>
> I'm really lost on this, only thing I can think of (SWAG) is (horrors)
> that the bed is crooked or perhaps the saddle is crooked?!???
>
> I'm really out of ideas, am I expecting too much of the 7x12?
>
> Thanks & take care, Vikki.
>
|
Re: Micromill vs Minimill .... Now milling attachment
Have you seen this? A friend has one, he is happy doing basic work, but he said it can only handle small cuts or he has a chatter problem. --- In 7x12minilathe@..., Richard Stevens <rtjstevens@...> wrote:
Hi, I too have a Seig 7x12 and have been wondering about milling too,
The smaller lathe has a milling attachment one can buy - but it
won't fit the 7x12 (I believe). Does anyone know of one that will fit? I do have a DVD from Chronos UK that shows a Taig/Peatol attachment (with a few minor mods) being able to fit the 7x10/12. Has anyone any experience of doing this? If so, what's the max capacity for milling?
I'm sure many will say - buy the Seig X-1/2/3 but Taig/Peatol also do a
standalone milling machine for approx ?550 (UK Pounds). Is this better than the equivalent mill from Seig?
Thanks
Richard (UK)
|
Re: Marvel Mystery Oil & lathes
If it's all you have on hand, it's better than nothing. I have used
it in all my pneumatic tools for thirty five years. Personally, I use
a syn 30wt on the lathe and mill cause it's what I have around. The
v-twin 50wt was a bit thick.
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., "rancerupp" <rupps@...> wrote:
I really don't wish to start ANOTHER oil thread. I followed some of the
recent ones (which were good) and gleened some good information from
them.
Just one simple question. Does M.M.O. have any place in the lathe
workshop? Thanks.
Rance
|
Re: Indexable bit holder for cummins mini lathe
Mine uses 5/16 according to the owners manual. I have a QCTP so I
have 5/16 and 3/8. I would think use the biggest you can.
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., "harleyknall" <knall@...> wrote:
I just got my cumming 7x12 mini lathe, it came with 5 crappy 5/16"
bits. They seemed to contact the work are a bit low, and needed to be
shimmed UP.
I like the idea of being able to use the indexable bits (3 sided)
what size shank should I be looking to get?
1/4 " ? 3/8"?
Thanks guys.
|
Re: Anybody know what this is?
Hi Mark, Check Frank Ford's site for how he adapted a similar large toolholder to fit his QCTP: Frank has lots of interesting ideas so his site is well worth checking out. The toolholder in the blurry picture looks like it is made for facing while the shank is mounted perpendicular to the spindle axis (the normal position). My tangential for the QCTP is similar in some ways since it can turn or face without changing position on the toolpost - depending on the shape of the bit, the blurry holder might be able to do the same. The difference would be the simplicity of making a jig to sharpen the tangential. John --- In 7x12minilathe@..., "markzemanek" <markzemanek@...> wrote:
Yeah, that 90 degree turn is a bit of a mystery alright.
It may not be out of the hands of the home shop machinist to build
his/her own tool holders. A short while back there was a discussion
about tangential tool holder, which for all purposes on our 7x's can
use 1/8" tool bits, and gadgetbuilder (where are ya' dude!...help me
out here...) has built a piece that sure inspires me. Before I can
make one, however, I am going to have to wait until I get myself a
mill...
Mark
==========
--- In 7x12minilathe@..., "Charles E. Kinzer"
<ckinzer@> wrote:
Did some minor searching and ETCO is Engineering Tooling Corp.,
"Quality Tools and Inserts for Swiss Style CNC Screw Machines"
A couple of the tool holders shown on their home page seem to hold
these inserts, just not at the 90 degree angle of the one on ebay.
The screw machine world is a bit of mystery to me. I suspect they
buy the "micro inserts" ready ground, and being small, they are cheaper.
I suspect it would be too much of a project to make a similar tool
holder for the home shop and use small HSS tool bits.
Chuck K.
----- Original Message -----
From: markzemanek
To: 7x12minilathe@...
Sent: Saturday, March 24, 2007 2:12 PM
Subject: [7x12minilathe] Anybody know what this is?
Howdy gang:
I've come across an interesting looking, alternative tool post on
ebay, of the likes I've never seen before.
The seller does not mentio what advantage it has over thet
nomral type tool post. The photo is quite poor, and the seller further seems
more interested in terms of payment.
Looking beyond all this, though, might anybody here know what the
application is for this type of toolpost?
Thanks, Mark
|
Re: Taper - I think I have a problem?!
G'day Vikki Your site shows you have a dial indicator. Mount it on the cross slide and extend the tail stock quill out to the limit of its travel and clamp it. Run the dial indicator along the side and top of the quill. You may well find the dial indicator moves during the travers indicating that the quill is not parallel to the bed axis. Unless you have spent time working over the tailstock you will find that it is too high by up to 20 thou and the the quill alignment is out by up to the same amount. I spent yesterday finally getting my tailstock to near "perfect" alignment and height yesterday, this has taken me 10 months of intermittent effort. I moved the clamping screw from under to above the foot. Don't use the rolling centre when making alignment; for critical work use a dead centre with the tip lubricated with molebdenum grease. I use the method which holds a shim between the centre to verify alignment. BTW. It turning between centres the alignment of the headstock will not effect the job. If the tailstock quill is not aligned then the alignment with the headstock will differ as the quill is extended. Keep up the work on the laser centre and edge finder, it looks a great project. One good turn deserves another. Regards, Ian --- In 7x12minilathe@..., "wrlabs" <wrlabs@...> wrote:
Hi Folks,
If I can poll the collective wisdom on this I'd appreciate it.
I'm not sure I have a problem, but I think so.
Turning down a rod I get a 0.015" difference over 5.5", please see:
I would guess that would turn into 0.030" over 11"?
If I turn a cone in the chuck and pull up the tailstock, they appear
to match up as near as I can tell.
My failed laser edge finder drew a circle around the the tailstock
center that looked centered to me.
I get this just turning a reasonably robust rod just clamped in the
chuck too (measurable difference between ends, forget what the value
is now).
I'm really lost on this, only thing I can think of (SWAG) is
(horrors) that the bed is crooked or perhaps the saddle is crooked?!???
I'm really out of ideas, am I expecting too much of the 7x12?
Thanks & take care, Vikki.
|
Re: Anybody know what this is?
Yeah, that 90 degree turn is a bit of a mystery alright. It may not be out of the hands of the home shop machinist to build his/her own tool holders. A short while back there was a discussion about tangential tool holder, which for all purposes on our 7x's can use 1/8" tool bits, and gadgetbuilder (where are ya' dude!...help me out here...) has built a piece that sure inspires me. Before I can make one, however, I am going to have to wait until I get myself a mill... Mark ========== --- In 7x12minilathe@..., "Charles E. Kinzer" <ckinzer@...> wrote:
Did some minor searching and ETCO is Engineering Tooling Corp.,
"Quality Tools and Inserts for Swiss Style CNC Screw Machines"
A couple of the tool holders shown on their home page seem to hold
these inserts, just not at the 90 degree angle of the one on ebay.
The screw machine world is a bit of mystery to me. I suspect they
buy the "micro inserts" ready ground, and being small, they are cheaper.
I suspect it would be too much of a project to make a similar tool
holder for the home shop and use small HSS tool bits.
Chuck K.
----- Original Message -----
From: markzemanek
To: 7x12minilathe@...
Sent: Saturday, March 24, 2007 2:12 PM
Subject: [7x12minilathe] Anybody know what this is?
Howdy gang:
I've come across an interesting looking, alternative tool post on
ebay, of the likes I've never seen before.
The seller does not mentio what advantage it has over thet nomral type
tool post. The photo is quite poor, and the seller further seems more
interested in terms of payment.
Looking beyond all this, though, might anybody here know what the
application is for this type of toolpost?
Thanks, Mark
|
Re: Taper - I think I have a problem?!
Thanks to all that responded to this query.
OK, I am *totally* intimidated after going through some of the websites
suggested :-(.
It is going to take a LOT more experience and especially more
understanding than I have before I start tearing down the lathe to that
degree.
Of interest, I dug out that bolster bar I made out of the 1" stainless
rod and measured that at each end (3") and it is only off by 0.001.
Chucked on one end, center drilled and supported by the live center in
the tailstock.
Wonder if my problem is flex in the workpiece, as in I am hogging it?
It would see that would make it off in the middle were it is unsupported
though.
Yep, I am totally confused about what is going on here.
The item that was off the 0.015 was wood and I am now wondering if the
centers being slightly off from the center marks (assuming they were
perfect) would cause that much difference? I would think that turning
that down would result in it being symmetrical / consistent from end to
end once it was turned down far enough?
Starting to think I really need a mentor or at least a decent course
about all this.
Thanks & take care, Vikki (The Massively Confuzed).
|
Re: Anybody know what this is?
Did some minor searching and ETCO is Engineering Tooling Corp., "Quality Tools and Inserts for Swiss Style CNC Screw Machines"
A couple of the tool holders shown on their home page seem to hold these inserts, just not at the 90 degree angle of the one on ebay.
The screw machine world is a bit of mystery to me. I suspect they buy the "micro inserts" ready ground, and being small, they are cheaper.
I suspect it would be too much of a project to make a similar tool holder for the home shop and use small HSS tool bits.
Chuck K.
toggle quoted message
Show quoted text
----- Original Message -----
From: markzemanek
To: 7x12minilathe@...
Sent: Saturday, March 24, 2007 2:12 PM
Subject: [7x12minilathe] Anybody know what this is?
Howdy gang:
I've come across an interesting looking, alternative tool post on
ebay, of the likes I've never seen before.
The seller does not mentio what advantage it has over thet nomral type
tool post. The photo is quite poor, and the seller further seems more
interested in terms of payment.
Looking beyond all this, though, might anybody here know what the
application is for this type of toolpost?
Thanks, Mark
|
Re: [SPAM] Anybody know what this is?
This is a tool holder and not a tool post. It would mount in a tool post.
It looks to me like it simply holds very small HSS tool bits, but in a way that gives them lots of support and contact. This would beef up the rigiditiy and would also helps with heat dissipation. So it would substantially let small tool bits act as if they were larger than they are.
I suspect the advantage is that you can grind a small tool bit a lot faster than a large one. And since only a small part of even a large tool bit typically contacts the workpiece, you aren't really giving up anything in most cases.
Chuck K.
toggle quoted message
Show quoted text
----- Original Message -----
From: markzemanek
To: 7x12minilathe@...
Sent: Saturday, March 24, 2007 2:12 PM
Subject: [SPAM] [7x12minilathe] Anybody know what this is?
Howdy gang:
I've come across an interesting looking, alternative tool post on
ebay, of the likes I've never seen before.
The seller does not mentio what advantage it has over thet nomral type
tool post. The photo is quite poor, and the seller further seems more
interested in terms of payment.
Looking beyond all this, though, might anybody here know what the
application is for this type of toolpost?
Thanks, Mark
|
Re: Anybody know what this is?
Nope, but I don't believe I'd buy from this ebayer. Must have had a nervous breakdown in Feb of this year. History can be seen at tinyurl.com/3884pk . You can use toolhaus.org to check neutral/neg. fb for ebayers. Rance --- In 7x12minilathe@..., "markzemanek" <markzemanek@...> wrote:
Howdy gang:
I've come across an interesting looking, alternative tool post on
ebay, of the likes I've never seen before.
The seller does not mentio what advantage it has over thet nomral type
tool post. The photo is quite poor, and the seller further seems more
interested in terms of payment.
Looking beyond all this, though, might anybody here know what the
application is for this type of toolpost?
Thanks, Mark
|
Anybody know what this is?
Howdy gang:
I've come across an interesting looking, alternative tool post on
ebay, of the likes I've never seen before.
The seller does not mentio what advantage it has over thet nomral type
tool post. The photo is quite poor, and the seller further seems more
interested in terms of payment.
Looking beyond all this, though, might anybody here know what the
application is for this type of toolpost?
Thanks, Mark
|
Indexable bit holder for cummins mini lathe
I just got my cumming 7x12 mini lathe, it came with 5 crappy 5/16"
bits. They seemed to contact the work are a bit low, and needed to be
shimmed UP.
I like the idea of being able to use the indexable bits (3 sided)
what size shank should I be looking to get?
1/4 " ? 3/8"?
Thanks guys.
|
Marvel Mystery Oil & lathes
I really don't wish to start ANOTHER oil thread. I followed some of the
recent ones (which were good) and gleened some good information from
them.
Just one simple question. Does M.M.O. have any place in the lathe
workshop? Thanks.
Rance
|
And that fractured English is a word for word copy of the Weiss website which Robin found. Weiss, Warco and Chester look identical in their respective photos. The only difference seems to be in the motor wattage: 700W at Chester, 550W at Warco, and less than either at Weiss. Unlike Warco, Chester don't mention imperial/metric leadscrew options.
Ellis Cory Robin wrote........The Chester rep said that it wasn't sourced from the same manufacturer as the warco lathe..........
No. not with this translation ' Casting iron change gears get greater capacity'
LOL
Ellis
---------------------------------
Copy addresses and emails from any email account to Yahoo! Mail - quick, easy and free. Do it now...
|
Re: Micromill vs Minimill .... Now milling attachment
hi Richard,
For that sort of money, you can buy this:
mind you, it'd take up quite a bit more space than a micro- or even a mini-mill.
You should be able to get a milling attachment for the mini-lathe - ?68 is the best price that I've seen, Sieg brand, too.
Hugh
(London UK)
Richard Stevens <rtjstevens@...> wrote:
Hi, I too have a Seig 7x12 and have been wondering about milling too,
The smaller lathe has a milling attachment one can buy - but it won't fit
the 7x12 (I believe). Does anyone know of one that will fit? I do have a DVD
from Chronos UK that shows a Taig/Peatol attachment (with a few minor mods)
being able to fit the 7x10/12. Has anyone any experience of doing this? If
so, what's the max capacity for milling?
I'm sure many will say - buy the Seig X-1/2/3 but Taig/Peatol also do a
standalone milling machine for approx ?550 (UK Pounds). Is this better than
the equivalent mill from Seig?
Thanks
Richard (UK)
[Non-text portions of this message have been removed]
|
Micromill vs Minimill .... Now milling attachment
Hi, I too have a Seig 7x12 and have been wondering about milling too,
The smaller lathe has a milling attachment one can buy - but it won't fit
the 7x12 (I believe). Does anyone know of one that will fit? I do have a DVD
from Chronos UK that shows a Taig/Peatol attachment (with a few minor mods)
being able to fit the 7x10/12. Has anyone any experience of doing this? If
so, what's the max capacity for milling?
I'm sure many will say - buy the Seig X-1/2/3 but Taig/Peatol also do a
standalone milling machine for approx ?550 (UK Pounds). Is this better than
the equivalent mill from Seig?
Thanks
Richard (UK)
|
Re: Taper - I think I have a problem?!
Leveling is the normal way (pun) that larger lathes are set up but the
minilathe is relatively stiffer due to its small size. Although the
castings aren't "aged", they are generally ground accurately so there
isn't any twist in the typical minilathe. Unless it is firmly bolted
down -- this can induce a twist, especially if bolted to something
that changes with humidity (wood) or temperature (metal) at a rate
different from the lathe bed itself. The simple rubber feet work well
because the lathe is light enough so it doesn't twist under its own
weight (as large machines may). (Hardinge made a large "portable"
lathe with wheels that was quite accurate so there is some precedence
for lathes not being bolted down.)
More commonly, tapers occurring in work held in the chuck (not between
centers) arise from poor alignment between the spindle and the ways.
This can be corrected by the owner with simple techniques but takes
several hours: Once
aligned the machine seems to remain aligned so this is a one-time
effort, i.e. the castings don't seem to "age" and twist.
John
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., "Ed Boysun" <boysungran@...> wrote:
Guys that should know, tell me that a lathe bed has almost no resistance
to twist. You need to beg, borrow, or steal a machinist's precision
level and check the bed, both at the headstock and near the tailstock to
make sure that the level reads exactly the same in both places. If your
bench is solid, you may need to add shims beneath the legs on the lathe,
then clamp it back to the bench. If your table is not completely rigid,
you can adjust the feet of the table to impart some twist to the table,
and thus to the lathe bed. It surprised me; just how much a small shim
will de-twist the bed. A twisted bed will exhibit exactly the symptoms
you describe.
Ed B
--- In 7x12minilathe@..., "wrlabs" <wrlabs@> wrote:
Hi Folks,
If I can poll the collective wisdom on this I'd appreciate it.
I'm not sure I have a problem, but I think so.
Turning down a rod I get a 0.015" difference over 5.5", please see:
I would guess that would turn into 0.030" over 11"?
If I turn a cone in the chuck and pull up the tailstock, they appear
to match up as near as I can tell.
My failed laser edge finder drew a circle around the the tailstock
center that looked centered to me.
I get this just turning a reasonably robust rod just clamped in the
chuck too (measurable difference between ends, forget what the value
is now).
I'm really lost on this, only thing I can think of (SWAG) is (horrors)
that the bed is crooked or perhaps the saddle is crooked?!???
I'm really out of ideas, am I expecting too much of the 7x12?
Thanks & take care, Vikki.
|
Re: Just got the cummins 7x12 need help with tooling
Some more ideas on grinding bits here: Rather than adjusting the angle of the grinder guide I used little wooden wedges marked with the angle and left the grinder guide horizontal. Recently I built the simple grinding jig from "Screwcutting in the Lathe". This jig sharpens threading bits quickly and accurately. In addition, by angling things properly via the 2 degrees of freedom provided, many other types of lathe tools can be ground accurately without the "facets" I generally wound up with. It does need a larger than normal guide table on the grinder, see: John --- In 7x12minilathe@..., "Mike Payson" <mike@...> wrote:
I had the exact same results as you using that cheapie carbide set.
I'm new to the lathe, so I'm far from an expert, but from my limited
experience and everything I've read, the others are on the right
track. You can buy a bench grinder from a company like Homier or
Cummins for as little as $15, and it will do the job just fine.
Varmint Al has examples of ground bits that you can follow at
(). Don't stress
out about getting it just right. It's a forgiving process. If the
angles are even close to those in the picture, you'll be just fine.
Don't worry if you don't have a diamond hone. I haven't honed my bits
& I've been getting great results. I have no doubt that when I get
around to buying a hone, the results will get even better, but for
now, I'm perfectly happy.
One more big advantage of learning to grind bits is when you need a
custom profile. Want a curved transition between surfaces? just carve
a bit in the appropriate shape. You probably won't be able to find a
premade bit with just the right profile...
On 3/23/07, harleyknall <knall@...> wrote:
It came with 5 bits.... I am unsure what each one is for.... But
I am sure I destroyed 2 of em learning to use the lathe on some scrap.
Ruined 1 by running the lathe in reverse....ruined the other
having it set to low in relation to the tailstock hight.
ANYWHO...... I think I know how to operate the thing now.
I need to get a "parting tool" a tool to thread with, and a "turning
tool"
Where to get ? what size to get? what style to get? as I
mentioned i have 5 difrant bits in front of me and I am oblivious
as to which is for what operation. Should the tool be mounted 90
degrees to the workpiece for all these operations?
Thanks guys, I got enough of a "feel" for the machine tonight
that I know it is MORE than enough machine for the task I need to complete.
Just need to know what bits to use for what operation, the bits I have
seen MOSTLY come labeled with stock #'s not USES labeled on em.
Be sure to check out for small
mills and lathes. Yahoo! Groups Links
|
Re: Taper - I think I have a problem?!
I have read that some folks have had a twist problem. Both my 10 and
14 in beds checked out good. I also use a piece of 24X6X3/8 steel
plate to mount the bed to, with the wide feet under that. Help cut
down on chatter when parting.
toggle quoted message
Show quoted text
--- In 7x12minilathe@..., "Ed Boysun" <boysungran@...> wrote:
Guys that should know, tell me that a lathe bed has almost no resistance
to twist. You need to beg, borrow, or steal a machinist's precision
level and check the bed, both at the headstock and near the tailstock to
make sure that the level reads exactly the same in both places. If your
bench is solid, you may need to add shims beneath the legs on the lathe,
then clamp it back to the bench. If your table is not completely rigid,
you can adjust the feet of the table to impart some twist to the table,
and thus to the lathe bed. It surprised me; just how much a small shim
will de-twist the bed. A twisted bed will exhibit exactly the symptoms
you describe.
Ed B
--- In 7x12minilathe@..., "wrlabs" <wrlabs@> wrote:
Hi Folks,
If I can poll the collective wisdom on this I'd appreciate it.
I'm not sure I have a problem, but I think so.
Turning down a rod I get a 0.015" difference over 5.5", please see:
I would guess that would turn into 0.030" over 11"?
If I turn a cone in the chuck and pull up the tailstock, they appear
to match up as near as I can tell.
My failed laser edge finder drew a circle around the the tailstock
center that looked centered to me.
I get this just turning a reasonably robust rod just clamped in the
chuck too (measurable difference between ends, forget what the value
is now).
I'm really lost on this, only thing I can think of (SWAG) is (horrors)
that the bed is crooked or perhaps the saddle is crooked?!???
I'm really out of ideas, am I expecting too much of the 7x12?
Thanks & take care, Vikki.
|
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