Hi Jim

OK if your lathe is cutting smaller at the head stock than it is out
in space your bed has a twist in it. Now this is figuring that the
head stock is in correct alignment and or your spindle bearings are
not shifted in the head stock.

I kind of think its not the bearings and this is why. First you say
the taper is .005 in 4 inches. Now the distance between bearings is
about seven inches. This would mean that your spindle would have to
be out of alignment with the head stock casting about .010 This I
find hard to believe though it could be.

First I would loosen all the bed mounting bolts were it is mounted
to the table or bench. I would let is sit for one week. Now I
would snug down the head stock end of the bed leaving the tail stock
end lose. Now take another sample cut and see what you get.
Remember these things are made from hard rubber and will move all
over the place.

If you find after a week of rest and relaxation your lathe is still
cutting a taper lets try shimming the bed and get the twist out of
it. You will have to put a shim under the front bed mount at the
tail stock end. You could also put a shim under the rear mount on
the head stock end. I am talking a shim of .015 or so. Now bolt
the bed back down and let it sit for a week and then check things
again to see if things are moving yet.

You all will be surprised at just how little it takes to get a lathe
out of whack. Also just how little it takes with patients to get it
back cutting nice and strait.

It took Dave Kirk several weeks to get his bed moved around to were
he was cutting no more than .0005 in a few inches. Don't remember
just what Dave came up with but I am sure he is going to let us
know. :-()

We have a lathe at work that is a 14 by 40 and we do a job that
requires us to check the alignment at the begging of the day and
after lunch. This job we are using a fixture in the head stock that
we machine the face each time we put it in the spindle. Then we
mount a custom made mandrel to this that is hardened and ground. On
this mandrel we mount the lens mount for an electron microscope that
has a bore of 1.120 +.0002 - .0000. This lens mount is 14 inches
long and has an outside diameter of 2 inches. Now we have to face
each end perpendicular to the bore to a tolerance of + or - .000050
and at the same time hold an overall length of .0001. Now we do this
on a TWS Taiwanese lathe that now has over 17000 hours on the run
meter. Dam fine machine but we are asking it to do something very
much out of the ordinary. So you say how do we do this. Well ever
time we set the job up we have to align the bed with the fixture in
place. We do this by traversing the mandrel with a .000050
electronic indicator. We need to have the mandrel aligned to .0001
in 14 inches. The lathe is fitted with four bed feet at each end of
the machine. This makes for real fun moving things. With this
setup we can actually hump the bed in the middle or belly it down as
well as twisting it. This lathe weights 3200 pounds so is no light
weight. I give this example just so you can see what can be done
with a lathe.

Turk


--- In daltonlathes@..., "Jim Bonner" <bogyjim@...>
wrote:

Hi all,

I'm wondering if someone could give me some advice on getting my
lathe to cut straight. The lathe is a Dalton B6. When I cut a

test

bar,(without a center in the tailstock) I get about .005 taper in

6

inches. The smaller diameter is at the headstock end. I would

think

that if it was a matter of normal bed wear, the smaller diameter
would be at the tailstock end. I have checked for bed wear by
mounting a travel indicator on the carriage and indicating off the
tailstock flat way. It doesn't indicate any wear that way.

I'm thinking that the spindle bearings aren't aligned with the

bed.

As I recall there is about .004 shim under the large spindle

bearing

halves to take up for wear in the bearing.

Any suggestions?

thanks, Jim Bonner

As to micrometers versus calipers. Well there is no contest here.
A caliper is only accurate to maybe + or - .001 and that is the very
best ones and in like new condition. A micrometer on the other hand
is a precise tool. Your standard micrometer must meet an AGG 1500
government specification to be sold in the US. Now US Japanese as
well as most European micrometers will pass with flying colors. I
still would not trust a Chinese micrometer to better than .0005.
This I say as we have asked employees to remove there Chinky
micrometer from the building as we find they just will not cut the
mustard.

At my business we have our measuring tools checked and calibrated
every six months. Any tool not meeting the grade are removed from
the building. Company tool or personal. Micrometers are tested to
this tolerance. Fist they anvils have to be dead flat and this is
checked with a device that uses wave lengths of light. Forget what
it is called. Next the micrometer is cleaned and the nut adjusted
for feel. Next it is checked every .100 and must be accurate to no
less than .00005. Most all of the micrometers out there today will
meet this requirement when new

So you see a caliper is good for quick roughing measurements but
when push comes to shove you need a micrometer. I use .00005
resolution digital electronic micrometers at work and here at home.
Trust them they work.

Turk
--- In daltonlathes@..., "Dave" <dkirk_4@...> wrote:

Hello everyone,
I was just looking at some tool catalogs, and it struck me that

since

all the calipers are listed as having accuracies of plus or

minus .001

in 6 inches, and most of the micrometers are listed as being plus

or

minus .0005-.00015 in 1", that the calipers are just as if not a

little

more than accurate as the micrometers. And a little more useful

since

you get more than one inch out of them.
But, if that is the case, I don't think anyone would be

spending

like 700 dollars on a set of 1-4" micrometers. Can someone

enlighten me

here? Or possibly point me to some information explaining this,

since

this might make for a pretty long post?
I'm also noticing that the digital stuff doesn't list the

accuracies

most of the time. But then there is a set of Mitutoyo 0-6"

micrometer

with interchangable anvils and the accuracy is listed as plus or
minus .0002 + .00005 x L/3 where L is the max. measuring length.

Pretty

concise listing, right? Then even Starret and Brown and Sharpe

will

only have the resolution listed. Very confusing. What gives here?

Dave Kirk

Hi gang,
What I ended up with on the Dalton was about .001 taper in 5 1/4"
towards the tailstock end. I checked this after a week and then after
two and three weeks and it stayed there but I haven't checked it
since. This was with a Baker back plunger indicator. It also
indicates 0 runout when I checked the taper in the spindle, so I know
it's good! ;-)

Back to the calipers for a moment. The calipers I have were listed
as being plus or minus .001 in six inches. I don't know how long
they'll stay that way, but out of the box, wouldn't that be plus or
minus .00016 an inch? ( .001/6 ) There are some Mitutoyo micrometers
here listed as being plus or minus .00015 in the 3-6 inch range. I
think maybe I just don't know what they mean when they talk
about .001 in 6". I don't suppose it really matters where the Dalton
is concerned anyway, I was just curious.

Ok, I hear some wicked thunder just the other side of the
mountains outside my window here. I'm gonna go check out the Dalton
on e-bay then I think I'll go see what the Dalton is up to taper-
wise.
Back later,
Dave

Ok guys, thanks for the response. Like Ron, at first I was thinking
headstock or spindle alignment. But the more I think about it, what
would cause that? I loosened the mounting bolts today (they weren't
real tight, just snug) and will wait a few days to try shimming.
I'll do as Dennis suggested and try .015 under the near foot at the
tailstock end. I'll keep you posted as to my progress.

Dave, as to your calipers, when they say accurate to +/- .001 at 6
inches, don't let that lead you to belive they are 6 times more
accurate at 1". Think of it as a linear thing. +/- .001 anywhere
between 0 and 6".

Jim



--- In daltonlathes@..., "Jim Bonner" <bogyjim@...> wrote:

Hi all,

I'm wondering if someone could give me some advice on getting my
lathe to cut straight. The lathe is a Dalton B6. When I cut a test
bar,(without a center in the tailstock) I get about .005 taper in 6
inches. The smaller diameter is at the headstock end. I would

think

that if it was a matter of normal bed wear, the smaller diameter
would be at the tailstock end. I have checked for bed wear by
mounting a travel indicator on the carriage and indicating off the
tailstock flat way. It doesn't indicate any wear that way.

I'm thinking that the spindle bearings aren't aligned with the

bed.

As I recall there is about .004 shim under the large spindle

bearing

halves to take up for wear in the bearing.

Any suggestions?

thanks, Jim Bonner

Ok, I'm back.
Would you believe I can't find my test bar? I think It got
misplaced and then used for something. Considering the meagre space I
have for my toys, it's not that unbelievable. So, I'm making another
one.
And that leads me to the first question here. How tight should you
tighten the three jaw chuck? I've been clamping it pretty tight. Just
short of leaving jaw marks I think. I like to think that whatever is
in there isn't going to move no-how! Is this bad for it?
And, what is best on my leadscrew? I put some "Super Impact
Grease" on it. This is just real sticky grease. I put it on the
change gears and it leaves little stringers between the gears while
the lathe is running. But I'm thinking that little metal chips are
going to get on there and the grease will be hell to get off of the
leadscrew so maybe oil is a better idea?

Ok, the calipers. So, the .001 deviation is anywhere in there,
whether you're in the one inch or five inch range, you could be off
by .001". And with the micrometer, you're only off by half that or
less. What exacly is the AGG 1500 standard? And, since the 8.00 ones
have to meet it like the 250.00 ones do, I would imagine that the
real expensive ones have hardened and ground threads and the like and
will retain their accuracy for more than a month? So what about the
digital micrometers, do they automatically adjust for error? Do they
wear out too?
All right, enough for one evening. Maybe I should just go bug one
of the sales people at Brown and Sharpe. Hey Dennis, can I use your
name so they know I'm legit? =8-O
I'm going to go slather some more grease on my leadscrew and use it
as an auto feed for me test bar. Thanks for the responses!
Oh yeah, does that Dalton come with an extra cross slide and top
slide or did that guy just take it off the lathe and lay it in his
driveway so he could get a better picture of it?
Dave

--- In daltonlathes@..., "Dave" <dkirk_4@...> wrote:

Dave the only thing that belongs to the Dalton is the cone pulley

on the morfidit countershaft and maybe one of the back plates he
calls a face plate would be usable. Other than the chucks there is
nothing Dalton. I have not a clue as to what that cross slide
compound thingy belongs to but its old rusty and beat. Same for the
milling thingy. Never seen one like this before and sure is not a
Dalton one.

Denny

Ok, I'm back.

Would you believe I can't find my test bar? I think It got
misplaced and then used for something. Considering the meagre

space I

have for my toys, it's not that unbelievable. So, I'm making

another

one.
And that leads me to the first question here. How tight should

you

tighten the three jaw chuck? I've been clamping it pretty tight.

Just

short of leaving jaw marks I think. I like to think that whatever

is

in there isn't going to move no-how! Is this bad for it?
And, what is best on my leadscrew? I put some "Super Impact
Grease" on it. This is just real sticky grease. I put it on the
change gears and it leaves little stringers between the gears

while

the lathe is running. But I'm thinking that little metal chips are
going to get on there and the grease will be hell to get off of

the

leadscrew so maybe oil is a better idea?

Ok, the calipers. So, the .001 deviation is anywhere in there,
whether you're in the one inch or five inch range, you could be

off

by .001". And with the micrometer, you're only off by half that or
less. What exacly is the AGG 1500 standard? And, since the 8.00

ones

have to meet it like the 250.00 ones do, I would imagine that the
real expensive ones have hardened and ground threads and the like

and

will retain their accuracy for more than a month? So what about

the

digital micrometers, do they automatically adjust for error? Do

they

wear out too?
All right, enough for one evening. Maybe I should just go bug

one

of the sales people at Brown and Sharpe. Hey Dennis, can I use

your

name so they know I'm legit? =8-O
I'm going to go slather some more grease on my leadscrew and use

it

as an auto feed for me test bar. Thanks for the responses!
Oh yeah, does that Dalton come with an extra cross slide and top
slide or did that guy just take it off the lathe and lay it in his
driveway so he could get a better picture of it?
Dave

Is the Dalton currently on ebay some sort of LOT 5? When I lightened
up the pics, it looks like a worm drive apron.

Jim

开云体育

Morning folks!
I was looking for federal micrometer spec's online this morning and
found this. Very interesting reading,check it out---

Gotta go to work, check back later
Dave

Good evening everyone,
Anyone else get a kick out of the Complimentary Small Plastic Ruler
Metrology?
So I'm just up from checking the taper on the B-4. I'm smaller at
the tailstock end by .006. Guess I know what I'll be doing this
weekend. Just for fun I checked with the calipers and the micrometer
and the calipers were off by a thousandth on the actual dimension but
the difference was the same.
Dave

Hello Dave,
What is the diameter of your test bar?

R.T. :D

--- In daltonlathes@..., "R.T." <redlupmi2@...> wrote:

Hello Dave,
What is the diameter of your test bar?

R.T. :D

At the moment, the test bar diameter is .946. I'm using a piece of
12L14 steel since I only have a 5/8 piece of aluminum that's long
enough. Last time I did this I started out with a 1" piece of aluminum
and it was just under 1/2" by the time I was done!
There is about 7" extending out the chuck, and I get some vibration
cutting down the tailstock end of the test bar, so I'm wondering if
maybe, due to the length, and there only being about two inches on the
other side of the chuck jaws since the spindle ID is only 3/4, if the
test bar is in there a little crooked. I think I should put some
smaller diameter stock in there just so I have plenty through the
spindle so I know it's in there straight, to see if I still come up
with the same .006 taper before I go any furthur.
Dave

Hello Dave,
I would bet the bar is flexing causing the taper. Larger diameter is
preferred, such as 2", can even be pipe or tubing.

The material behind the chuck shouldn't matter as long as it is well
secured. TIGHT in the chuck. Don't want the part rocking there either.

Let's see if Dennis agrees. :o)

R.T. :D
The Notorious Alabama Dalton Gangster

--- In daltonlathes@..., "Dave" <dkirk_4@...> wrote:

Morning folks!
I was looking for federal micrometer spec's online this morning

and

found this. Very interesting reading,check it out---

Gotta go to work, check back later
Dave

Thanks for the link Dave. My full time position is that of an an
Optical Manufacturing Engineer for a leading Metrology company (Zygo
Corp). We make some of the stuff NIST uses and we all use the SRPs.
I'm going to print this out and also forward the link to several co-
workers

Ron Peeler
B-4 Owner


--- In daltonlathes@..., "Dave" <dkirk_4@...> wrote:

Morning folks!
I was looking for federal micrometer spec's online this morning

and

found this. Very interesting reading,check it out---

Gotta go to work, check back later
Dave

Good evening gentlemen,
Well, it turns that at least some of the taper is due to the chuck
jaws. I can fit a .002 feeler gage in between the jaws and the work.
Sooo, anybody know if there are jaws still available for a Cushman, or
is it time for a new chuck?
Dave

Hi gang,
I almost forgot to ask if anyone needs any parts for their Daltons.
The one on ebay is just an hour away, so I'm wondering what the parts
situation is out there. Let me know if I should go get this baby.
Glad you enjoyed the CSPR metrology link Ron. I figured somebody else
would get a kick out of it.
Dave

Hi gang

OK there are two face plates up on eBay right now and stay away from
them as I am going to win them. 7631116925 is one of them.

I have one more just like these here now and I am going to open
these up to Dalton spindle size. Now John Gland has spoke for one
of them but the other two will go to the first and second guy that
emails me telling me he wants one. These I think are wood working
face plates but are 6 1/4 inch in diameter and are just a little
lighter than an original Dalton but they will work just great.

The cost is what ever the face plates plus shipping and $35 for my
time to put the thread in them. These will be fit to one of my best
spindles so I know they will work on yours. 1 1/4 - 12 and will not
work on the TL except Todd Young's.

Todd has a very strange TL. First all the Dalton cast in letters
have been ground off and there was a flat sheet metal plate riveted
to the front of the bed covering the big cast Dalton TL letters
there. The spindle is 1 1/4 -12 not 1 1/2 - 8 like all the other
TL's If I remember right he has a odd serial number also. May have
been a prototype that was sold of or was made for some other company
that the tags have been lost from the lathe. The oiling chain that
carries oil up to the spindle is also different than all the other
ones we know of. I have been helping Todd with getting his lathe up
and running. He restores old tractors and little parade cars. Todd
lives in St Louis and he has a model T that is just like the one I
am working on for a niece.

Anyway take a look at the eBay auction and if you wont one of these
two providing I get them let me know.

Owe and I would not use anything under 1 1/2 inches for a test bar.

Turk

开云体育

Hi Ed,

No, it wouldn't matter which direction you were cutting. The taper
is a result of a changing distance between the tool point and the
spindle axis.


Dave, your chuck may not be a factor in your taper. If the test bar
is tight and not moving in the jaws, a little clearance at the ends
of the jaws wont matter. As others have mentioned, the test bar
should fairly large in OD. I'm using a piece of 1 3/4" 6061. I
think the journals are down to about 1.680 now with a slightly
smaller relief in between.

Yes, I can see a new chuck in your future.... :-) Your chuck is
probably worn to a point where new jaws wouldn't help. Even if you
got new jaws, it's my understanding that they would have to be ground
to to match your chuck. I wonder if Dennis has a trick to "load" the
jaws under tension so you could use a boring bar to true up your
existing jaws.

Jim




--- In daltonlathes@..., "Ed stoller" <edstoller@...>
wrote:

As a non machinist lurking in the background here, I wonder if the

taper would be the same if you cut from right to left and left to
right. I have the same problem with my Senica Falls 103 year old
lathe which is very worn and had been abused.

Ed Stoller
New Fairfield, CT


----- Original Message -----
From: Dave
To: daltonlathes@...
Sent: Wednesday, June 21, 2006 7:49 PM
Subject: [daltonlathes] Re: Taper


Good evening gentlemen,
Well, it turns that at least some of the taper is due to the

chuck

jaws. I can fit a .002 feeler gage in between the jaws and the

work.

Sooo, anybody know if there are jaws still available for a

Cushman, or

is it time for a new chuck?
Dave