MT3 1" Slitting Saw Arbor

i started construction on a MT3 slitting saw arbor from materials in the shop.

here is the slug of what i believe to be 12L14 mild steel.
it was unmarked, but acted like 12L14 i have machined before.
it's very nice to turn.


the slug was a fraction over 1" in diameter and 7" long.
i centerdrilled both ends.
i turned the diameter on both ends down to .950".
one for the drive dog, the other to make the taper turning operation quicker



then i added the drive dog and offset the tailstock to a total indicated offset of .176"
and started cutting the taper


and after taking some passes, the arbor partially emerged from the rod!



i drilled & tapped the drawbar end to 3/8"-16 tpi x 1.250" depth and polished it up a bit more to fit into the MT3 test socket.
and here is the blank, pictured next to a MT2 blank i did the day before.



in the next episode...
i turn the cutter seat!
i'll do that inserted into the spindle of my Hercus ARH922.

Same Bat Time, Same Bat Channel!!!

 

you have a taper attachment on that? I can't see it. Or did you offset your tailstock.

 

you have a taper attachment on that? I can't see it. Or did you offset your tailstock.

Hi woodchucker,
i offset the tailstock

 

I can't make out the dog, can you post a picture of of it if you mount it up again?

 

Mike,
Nice work as usual, and great documentation.
Evan

 

I can't make out the dog, can you post a picture of of it if you mount it up again?

Hi middle.road,
the dog is a salvaged and modified collar guide from a meat processing machine.
the collar has weldment at 90° to the bore and has a 1" opening, and seemed like a convenient drive dog
i can post a picture when i get back home

Mike,
Nice work as usual, and great documentation.
Evan

Thanks Evan,
i'm happy you like it.
it was a lot of fun to make

 

Looks good, Question, How do you do you figure the offset for the tail stock.

 

UD, please don’t do anymore until I get more popcorn. I’ll be right back!…Dave

 

Looks good, Question, How do you do you figure the offset for the tail stock.

Hi kvt, thank you very much!

to find the tailstock offset, i used this formula courtesy of @Halligan142 as follows,

Tailstock Offset (T O ) = (length of work X Taper Per Foot)/24, then round the product of the equation up to the next thousandth of an inch

in my case it worked like this for the MT3 taper .6024" per foot, the blank was 7.00" long ...

T O= (7 X .6024)/24
T O= 4.2168/24
T O= .1757", then round up to the next thousandth
T O= .176"
i set the offset by placing an indicator on my saddle aft of the compound rest,
and indicated the vertical flat casting of my tailstock, near the the tailstock quill.
i loosened the tailstock offset adjusting screw on the operator side and tightened the tailstock adjusting screw until i achieved .175" offset.
then i started to re-tighten the offset screws tightening one against the other until i settled at the final .176" offset

 

Thanks
I need to get me a little book to put some of these formulas in. And for some reason I would have had it reversed as I would have had the flair on tapper backwards. I was thinking going away from the op.