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Lew Hartswick
01-31-2011, 07:42 PM
I'm trying to cut a couple threading indicator "gears" (a couple of the lathes
seem to have eaten a few teeth) (don't ask me how, I cant figure it
out either)
Since the gear has 40 teeth and that gizintas 360 so nice and even at
9 deg I thought the Spindex would be the easiest to use since it can
incerement in 1 deg steps. WELLLLL, I just finished the first experiment
and it seems to have picked up an error. By the time I got back to 0
the cutter did NOT hit the first 0 location by about an 1/8 of an inch
on a blank 3.15" dia.
Picture 1
http://i233.photobucket.com/albums/ee238/LewHartswick/DSCF0009.jpg

So the mandrel or the collet must have sliped but by looking at the
teeth there is no obvious discontinuity and going back over the
locations it is obvious that it is some gradual error. ie. checking at
90, 180, and 270 the error is gradualy increasing. Now the spindex
just can't pick up a gradual error it has to come back to 0 and be
the same place. So figure it must be the way I turn the wheel or be
related to that.

Next IDEA have a couple dividing heads as follows:

http://i233.photobucket.com/albums/ee238/LewHartswick/DSCF0010.jpg

http://i233.photobucket.com/albums/ee238/LewHartswick/DSCF0011.jpg

Problem is the Ellis has a 1 3/4 - 8 thread and a B & S 9 taper bore
the Japinese one has a 1 1/4 - 8 thread and some small taper bore
and the only 3 jaw chuck I have is 1 1/2 -8 thread and the mandrel
is 5/8 shaft.

Now two questions; 1 what is going on with the Spindex or
2 How can I hold the 5/8 shaft in either of the dividing heads?
Thanks.
...Lew...

Toolguy
01-31-2011, 07:49 PM
Could the gear be slipping on the arbor as it's being machined?

mmc005
01-31-2011, 08:07 PM
Have you tried reversing direction starting at 360 degrees and going backwards(don't forget about backlash) to see if there is any error in your head? I doubt there is, but if you can't see any visible error in the cut teeth then maybe it is in the head, the more you rotate the head the greater the error maybe?

Lew Hartswick
01-31-2011, 08:09 PM
Could the gear be slipping on the arbor as it's being machined?
Nope it's pined to the shaft.

Lew Hartswick
01-31-2011, 08:10 PM
Have you tried reversing direction starting at 360 degrees and going backwards(don't forget about backlash) to see if there is any error in your head? I doubt there is, but if you can't see any visible error in the cut teeth then maybe it is in the head, the more you rotate the head the greater the error maybe?
When I got back to 0 it was off , so something had to slip but it appears to have been a tensy bit each time. :-)

Toolguy
01-31-2011, 08:16 PM
Maybe the shaft is slipping in the collet. I have used spin jigs a lot over the years. The index plate is solid with no backlash like a worm and gear. Maybe the index plate is slipping. Something has to be moving to not come back to zero.

Bob Ford
01-31-2011, 08:23 PM
It appears that you are using a 5C collet. Could the arbor be slipping in the collet. I suspect a slightly dull cutter on one side.

Bob

lane
01-31-2011, 08:33 PM
When you retract the pin in the spindex to rotate it .Are you sure you are putting it back in the correct hole to lock in the 9 degree movement.I do not have my indexer in front of me but I think you have to back up one hole each time you index . If you use the same hole you get 10 degree per index . so buy moving back one hole each index you get 9 degrees . i can get very confusing.I think that is the problem.
You can use the dividing head working between centers the Brown ans Sharp copy has a #7 brown and Sharp taper The other as you said has a B&S #9 taper
Use the Ellis head and the center . A whole lot simpler and easier to do.

John Stevenson
01-31-2011, 08:35 PM
The index plate on a spin indexer isn't normally pinned or keyed, just pressed on.
Try that first.

Toolguy
01-31-2011, 08:38 PM
Some are threaded on, but not keyed or pinned, so they can come loose from vibration. LocTite fixes that.

John Stevenson
01-31-2011, 08:45 PM

For every 9 degrees it's not straight forward. Start at zero,
second hole is #9 in the vernier scale and move one way to the next hole so the pin engages, ignore the marking on the plate, these are full degrees only.
then you need to go 18 degrees which is one full hole an #8 in the vernier scale that lines up with the nearest hole going the same way.

Then 27 degrees which is two full holes and #7 on the vernier etc, etc.

Pays to have a list made up of the holes and numbers.

lane
01-31-2011, 09:13 PM

For every 9 degrees it's not straight forward. Start at zero,
second hole is #9 in the vernier scale and move one way to the next hole so the pin engages, ignore the marking on the plate, these are full degrees only.
then you need to go 18 degrees which is one full hole an #8 in the vernier scale that lines up with the nearest hole going the same way.

Then 27 degrees which is two full holes and #7 on the vernier etc, etc.

Pays to have a list made up of the holes and numbers.

Yes just what I though.

mmc005
01-31-2011, 11:22 PM
John and Lane, thanks for that info. I never knew that about those indexers.

Dave

Lew Hartswick
01-31-2011, 11:44 PM
Yes folks I know how to use the vernier on the indexer. :-) I even made up a table of the 40 values to so I wouldn't get confused adding 9
So how can I use one of the dividing heads I have ? The pin in the index
holes is a sticky bit and loosening the clamp and tail stock each time
is just as bad. The dividing head would be the nice way especially
since they both are 40 : 1 it would just be one turn of the crank.
...lew...

Oldbrock
02-01-2011, 12:30 AM
I have an Ellis dividing head that had a 1 3/4 - 8 thread but my southbend has a 1 1/2" 8 so all my chucks are that size. I took the dividing head apart and rethreaded the dividing head spindle 1 1/2" 8 so my chucks fit.. I can now take the chuck of the lathe with a part ready to be milled and put it on the dividing head without disturbing the part in the chuck. Worked out for me. Peter

Lew Hartswick
02-01-2011, 10:25 AM
I have an Ellis dividing head that had a 1 3/4 - 8 thread but my southbend has a 1 1/2" 8 so all my chucks are that size. I took the dividing head apart and rethreaded the dividing head spindle 1 1/2" 8 so my chucks fit.. I can now take the chuck of the lathe with a part ready to be milled and put it on the dividing head without disturbing the part in the chuck. Worked out for me. Peter
Now there is a winner but it will take a bit more time than I was
hopeing to use for this. :-) How much material is left between the
B&S taper and the thread? I'll look today at school. The other div.
head is so nice wish I could come up with a way to use an arbor in
it. Some sort of a drawbar or...or.. ? Or find a 3 jaw with a 1 1/4
Thanks fo the idea.
...lew...

John Stevenson
02-01-2011, 11:07 AM
The other div.
head is so nice wish I could come up with a way to use an arbor in
it. Some sort of a drawbar or...or.. ? Or find a 3 jaw with a 1 1/4
Thanks fo the idea.
...lew...

Determine if it is a Morse taper or B&S and if Morse get a MT2 x 5/8" weldon end mill holder for the short period.
Long time look at a MT2 to ER32 collet chuck ?

Lew Hartswick
02-01-2011, 12:54 PM
Determine if it is a Morse taper or B&S and if Morse get a MT2 x 5/8" weldon end mill holder for the short period.
Long time look at a MT2 to ER32 collet chuck ?
I don't know what the small one is but it's smaller than a Morse 2 ,
the Ellis is a Brown and Sharp #9 According to the manual. (no manual
for the small Japaneese one)( I forget the name and I'm at home now
due to a "school closed due to snow" )
Wonder if I could make a B&S taper on a stub with a 1 1/5 thread to
hold the 3 jaw I have, it would probably need a "draw bar" to insure
it didnt come loose while machining. Hummmmm!
...lew...

lane
02-01-2011, 08:32 PM
I don't know what the small one is but it's smaller than a Morse 2 ,
the Ellis is a Brown and Sharp #9 According to the manual. (no manual
for the small Japaneese one)( I forget the name and I'm at home now
due to a "school closed due to snow" )
Wonder if I could make a B&S taper on a stub with a 1 1/5 thread to
hold the 3 jaw I have, it would probably need a "draw bar" to insure
it didnt come loose while machining. Hummmmm!
...lew...

Read post #8 it is all their.

Oldbrock
02-02-2011, 03:46 PM
Lew, lots of meat left between the taper and the thread. Looks like it was born that way. Peter