I am going to make a threading dial for my Jet 1024. It seems pretty
straight forward, but I want to do a sanity check and ask a couple of
questions.

1. My Logan 200 and the Jet have the same lead screw (8 tpi). I assume
that this means I should use a 16 tooth dial gear, as that is what the
Logan has.

2. The lead screw looks like an Acme thread, could it be something
else? If so, how would I figure out what it is?

3. What is this kind of gear called? I.e., when I call Boston Gear,
what should I say I need? Is "To fit an 8 tpi Acme thread sufficient"?

Thanks,
Bob

In article ,
Bob Engelhardt wrote:

I am going to make a threading dial for my Jet 1024. It seems pretty
straight forward, but I want to do a sanity check and ask a couple of
questions.

1. My Logan 200 and the Jet have the same lead screw (8 tpi). I assume
that this means I should use a 16 tooth dial gear, as that is what the
Logan has.

2. The lead screw looks like an Acme thread, could it be something
else? If so, how would I figure out what it is?

3. What is this kind of gear called? I.e., when I call Boston Gear,
what should I say I need? Is "To fit an 8 tpi Acme thread sufficient"?

Since there is no load on the teeth, tooth form is not important.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

I agree with Nick. The form is not important. But I am pretty sure
that the form for mating with a Acme thread is a 14.5 pressure angle.
Dan


Nick Hull wrote:

Since there is no load on the teeth, tooth form is not important.

--
Free men own guns, slaves don't
www.geocities.com/CapitolHill/5357/

In article ,
says...

3. What is this kind of gear called? I.e., when I call Boston Gear,
what should I say I need? Is "To fit an 8 tpi Acme thread sufficient"?

Ignoring the tooth form, which Nick has responded to, you
won't be able to buy a stock gear of the proper pitch. If I
did the math right, you'd need a 25.133 diametral pitch
gear (8 x pi), or a 1.01 Module (metric) gear. Huh, maybe
you could get away with a 1.0 Module.

I don't think McMaster carries Module gears, you can get
them from Ametric if you're willing to give it a try.

http://www.ametric.com/home.htm

Since the tooth form will be wrong, you might consider a
design that would allow disengaging the thread dial when
it's not being used, especially if this is a lathe that
doesn't have a separate shaft for the regular feeds, i.e.,
the lead screw is always turning.

Ned Simmons

On Sun, 07 Aug 2005 15:31:37 -0400, Bob Engelhardt
wrote:

I am going to make a threading dial for my Jet 1024. It seems pretty
straight forward, but I want to do a sanity check and ask a couple of
questions.

1. My Logan 200 and the Jet have the same lead screw (8 tpi). I assume
that this means I should use a 16 tooth dial gear, as that is what the
Logan has.

2. The lead screw looks like an Acme thread, could it be something
else? If so, how would I figure out what it is?

3. What is this kind of gear called? I.e., when I call Boston Gear,
what should I say I need? Is "To fit an 8 tpi Acme thread sufficient"?

Thanks,
Bob


Hi Bob,
I'm not sure if this helps or not, but the threading dial I use on my
1024 (the twin of yours...) is from a 9" South Bend, same 8TPI lead
screw, but the gear on the threading dial is 32 teeth. I stumbled on
the SB indicator and having nothing to lose, just tried it on my Jet,
which did not have one when I got it. Nice smooth operation with
minimal slop. Works fine.

I am pretty sure that someone else here can tell you what sort of
thread form a SB uses. Should be close enough.

-AL A.

PS, how did you make out with the backgears? Did you get that
all straightened out?

-AL

Nick Hull wrote:
Since there is no load on the teeth, tooth form is not important.

Good point. That will make one easier to find. Except ...

Ned Simmons wrote:
Ignoring the tooth form, which Nick has responded to, you
won't be able to buy a stock gear of the proper pitch.

Oh, no! That means I'll *have* to buy a dividing head (to make my own
gear on the mill). I'm sure that my wife will understand. VBG

If I did the math right, you'd need a 25.133 diametral pitch
gear (8 x pi)...

IIRC, the formula: (# teeth + 2) / OD gives the DP. In this case:
(16+2)/.715 = 25.17. Pretty close - it has to be an approximation, that
"teeth + 2" is just too simple to be dead on.

Since the tooth form will be wrong, you might consider a
design that would allow disengaging the thread dial when
it's not being used, especially if this is a lathe that
doesn't have a separate shaft for the regular feeds, i.e.,
the lead screw is always turning.

I'm just using the basic design from the Logan (a pivoting assembly),
which allows disengagement. But the Jet does have a separate lead
screw, so I'm covered twice.

Thanks for the replies,
Bob

There is an article on making said gear with a lathe on a the yahoo
SB10k group. Its a jpg file if you want it email me (despam my
address), also one of HSM magazines had a recent article on hobbing a
threading dial gear. Looks like a interesting project, I made a
thread dial but bought the gear.

DE


Hi Bob,
I'm not sure if this helps or not, but the threading dial I use on my
1024 (the twin of yours...) is from a 9" South Bend, same 8TPI lead
screw, but the gear on the threading dial is 32 teeth. I stumbled on
the SB indicator and having nothing to lose, just tried it on my Jet,
which did not have one when I got it. Nice smooth operation with
minimal slop. Works fine.

I am pretty sure that someone else here can tell you what sort of
thread form a SB uses. Should be close enough.

-AL A.

PS, how did you make out with the backgears? Did you get that
all straightened out?

-AL


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

I am going to make a threading dial for my Jet 1024. It seems pretty
straight forward, but I want to do a sanity check and ask a couple of
questions.

1. My Logan 200 and the Jet have the same lead screw (8 tpi). I assume
that this means I should use a 16 tooth dial gear, as that is what the
Logan has.

2. The lead screw looks like an Acme thread, could it be something
else? If so, how would I figure out what it is?

3. What is this kind of gear called? I.e., when I call Boston Gear,
what should I say I need? Is "To fit an 8 tpi Acme thread sufficient"?

Thanks,
Bob
check this out.... ebay item #7536944404
I have an Craftsman/Atlas 12x36 with 8TPI leadscrew and this
one is the same as mine. Will probably work on yours. Bolts to the
apron, loosen mounting screw and the unit swivels away from the lead
screw to disengage.
HTH
Ken.

Al A. wrote:
... the threading dial I use on my
1024 (the twin of yours...) is from a 9" South Bend, same 8TPI lead
screw, but the gear on the threading dial is 32 teeth. ...

Your dial is rotating at half the speed (relative to the lead screw) as
a 16 tooth dial. Does that mean that your dial has twice as many marks?
There are 4 marks on my Logan dial: "1" & "2" 180 degrees apart and a
"|" between them.

PS, how did you make out with the backgears? Did you get that
all straightened out?

The bushings on the spindle pulley were badly scored, so I replaced
them. Of course, they were not a standard size, so I had to turn them to
fit (Catch 22 - I needed a lathe to fix my lathe). Boring them out
wasn't a big deal, but one of them had a *taper* on the OD!

Re-assembling it was a lot easier after boring out the bull gear a
smidgen. After it was all assembled and I added oil to the reservoirs I
discovered that the inboard seal on the outboard bearing was bad
(leaked). It would have been easy to replace, but I'm not going to take
it apart again just for that seal. I'll just keep adding oil.

Bob

Response top posted:
Hi Bob
If you can get your hands on a copy of the Home Shop Machinist,
May/June 2000, page 38, Peter Lott has a four page article called "
the Lathe Thread-Chasing Dial- - - Lathes with Inch-Thread Screws".
He goes into the whys, hows and wherefores of the threading dials and
how he made one for his 12" Seneca Falls Star lathe. Lots of good
info including how he calculated the drive gear. Also a 'Thread
Chasing Dial Table' for use with even and odd thread lead screws.
Best of luck
Bob

On Sun, 07 Aug 2005 15:31:37 -0400, Bob Engelhardt
wrote:

I am going to make a threading dial for my Jet 1024. It seems pretty
straight forward, but I want to do a sanity check and ask a couple of
questions.

1. My Logan 200 and the Jet have the same lead screw (8 tpi). I assume
that this means I should use a 16 tooth dial gear, as that is what the
Logan has.

2. The lead screw looks like an Acme thread, could it be something
else? If so, how would I figure out what it is?

3. What is this kind of gear called? I.e., when I call Boston Gear,
what should I say I need? Is "To fit an 8 tpi Acme thread sufficient"?

Thanks,
Bob

rgentry_at_oz_dot_net
_AT_ = @, _dot_ = . to eMail

Ned Simmons wrote:
... you
won't be able to buy a stock gear of the proper pitch. ...

I just found a gear! The Logan company has a replacement gear. But ...
it's $45 gasp!. I happen to have a '71 Logan parts catalog where that
part is $5.75. A vivid example of the power of compounded inflation -
that is only about 6% per year, compounded.

I think that I'll keep looking,
Bob

It really isn't that hard to make one. You need to make a hob by
making a copy of your lead screw (left hand thread), mill a couple of
teeth and relieve it. Make a mount for your toolpost for the blank to
rotate, put the hob in the spindle between centers, and advance the
blank into it. You don't even have to harden the hob it you make a
brass gear.

It helps to gash it first to be sure you get the right number of teeth,
otherwise you might get one mor or less than you need. A spin indexer
is close enough for this step.

To make the hob without a threading dial, just don't disengage the half
nuts. It gets a little tedious and you may have to rotate the spindle
by hand at times, but it can be done.

For a threading dial, you could make the gear out of various plastics.
Nylon and Deldrin would probably be better choices, but I have made
gears out of Lexan ( Hey it was what I had ).

Dan


paul wrote:
You don't even have to harden the hob it you make a
brass gear.

paul wrote:

... make one. ... make a hob ... Make a mount ... make a
brass gear.
...

Oh - I like that. Another skill curve to climb ("because it's there").

Bob

wrote:
... make the gear out of ...
Nylon and Deldrin ...

Good idea - I have some stuff in "the pile" that might be good.

I suppose I could even cast one. I have the Logan gear as a pattern. I
could make a mold and cast in reinforced epoxy. But the hobbing idea is
cooler.

Bob

DE wrote:
There is an article on making said gear with a lathe on a the yahoo
SB10k group. ...

Thanks. I "joined" the group and found the article.

Ken Sterling wrote:
check this out.... ebay item #7536944404 ...

Duh - why didn't I think of that. eBay! Of course - you can get
anything on eBay.

I checked the Completed auctions - there were some dials that were
bargains and some weren't ($110??? - no way).

Thanks,
Bob

Bob Gentry wrote:
... Home Shop Machinist,
May/June 2000, page 38, Peter Lott has a four page article called "
the Lathe Thread-Chasing Dial- - - ...

Just what I need! HSM doesn't have that back issue and none of the
Massachusetts libraries subscribe, but I'll have our librarian do a
nationwide search (ain't the 'net wonderful?).

Thanks,
Bob

Bob
My Enco 1024 has an original threading dial.
I also have an Atlas 10" thread dial and a Logan 9 with thread dial.
I'd be happy to make any measurements or comparisons that would help.

- -
Rex Burkheimer
WM Automotive
Fort Worth TX

Rex B wrote:
....
I'd be happy to make any measurements or comparisons that would help.

Thanks, I think that I'm all set. I've been looking around and I'm
pretty confident about it. I was kinda in the dark about the number of
teeth on the gear. Scott Logan (I think it was) in a Yahoo post
explained it: the number of gear teeth divided by the screw tpi gives
the highest number on the dial. E.g., 16 / 8 = 2, the dial has "1" &
"2". The number gives the fractional pitch possible. E.g., 1/2 for 2,
1/4 for 4.

Bob

In article ,
Bob Engelhardt wrote:
Al A. wrote:
... the threading dial I use on my
1024 (the twin of yours...) is from a 9" South Bend, same 8TPI lead
screw, but the gear on the threading dial is 32 teeth. ...

Your dial is rotating at half the speed (relative to the lead screw) as
a 16 tooth dial. Does that mean that your dial has twice as many marks?
There are 4 marks on my Logan dial: "1" & "2" 180 degrees apart and a
"|" between them.

My 12x24" Clausing (with an 8 TPI leadscrew) has four numbered
markings 1, 2, 3 & 4, with four index marks half way between them. I
suspect that is what you would need with a 32 tooth pickup gear.

BTW One thing which I have not seen mentioned yet in this thread is
that you will either have to cut your teeth at a slight angle
(to match that of the Acme thread on the leadscrew), or to mount
the shaft of the dial at an angle to allow the gear faces to
line up with the leadscrew thread. It is not much of an angle
(precisely how much depends on the diameter of the leadscrew in
combination with the thread pitch. (It calculates out to 2.28
degrees with a 1" diameter 8 TPI leadscrew.) In either case,
you may have to make corrections to the gear form to compensate
for the angle.

Be glad that you're not making a threading dial for a Metric
leadscrew. That has to have four different gears -- all of which mesh
with the leadscrew, one at a time, to handle all of the pitches common
in the metric system. (This is one of the places where the Imperial
system works out easier, because so many of the threads are a power of
two relationship with other threads.) When you need to handle a 1.00mm,
0.80mm, 0.60mm, 0.45mm and other such, the design of a threading dial
gets a bit more complex. And, of course, there is an additional bit to
the threading charts to tell you which pickup gear to use with a given
thread. :-)

Good Luck,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Bob Engelhardt wrote:
I am going to make a threading dial for my Jet 1024. ...

Thanks for all the replies in this thread. I have finished my dial,
after many distractions. Here is a pictu
http://home.comcast.net/~bobengelhardt/thread-dial.jpg

I made the gear by hobbing a piece of plastic, unknown lineage. But it
machined real nice - long smooth curls, very waxy in appearance. And
strong (tensile). The threading dial that I copied had a spur gear, but
I cut a worm wheel, to fit the worm lead screw. The tool I ground to
cut the hob was not very precise, but it works. I "gashed" the gear on
the lathe by using the feed gear train to step the spindle. I also
hobbed the gear on the lathe with the hob between center and by making a
blank holder to fit the lathe tool holder.

There is a spring under the head of the mounting SHCS. It supplies
enough pressure to hold the gear against the screw, but allows the dial
to be swung away.

Thanks again,
Bob

Bob Engelhardt wrote:
I am going to make a threading dial for my Jet 1024. ...

Thanks for all the replies in this thread. I have finished my dial,
after many distractions. Here is a pictu
http://home.comcast.net/~bobengelhardt/thread-dial.jpg

I made the gear by hobbing a piece of plastic, unknown lineage. But it
machined real nice - long smooth curls, very waxy in appearance. And
strong (tensile). The threading dial that I copied had a spur gear, but
I cut a worm wheel, to fit the worm lead screw. The tool I ground to
cut the hob was not very precise, but it works. I "gashed" the gear on
the lathe by using the feed gear train to step the spindle. I also
hobbed the gear on the lathe with the hob between center and by making a
blank holder to fit the lathe tool holder.

There is a spring under the head of the mounting SHCS. It supplies
enough pressure to hold the gear against the screw, but allows the dial
to be swung away.

Thanks again,
Bob
Nice, Bob. However, the "spring under the head of the SHCS" has me
concerned. Do you tighten the SHCS to "prevent" the gear from moving
away from the lead screw? If not, I think I would recommend that you
do, to prevent a little piece of swarf from making your dial "jump a
tooth" when you're not looking..... could ruin a good project someday
G Glad you're now ready to start doing some threading.....
Ken.