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MT3 1" Slitting Saw Arbor

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[10] Like what you see?
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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.
IMG_2568.jpg

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

DSCN0012.JPG

then i added the drive dog and offset the tailstock to a total indicated offset of .176"
and started cutting the taper
DSCN0013.JPG

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

IMG_2569.jpg

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.

DSCN0015.JPG

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!!!
 
#2
you have a taper attachment on that? I can't see it. Or did you offset your tailstock.
 
#4
I can't make out the dog, can you post a picture of of it if you mount it up again?
 
#5
Mike,
Nice work as usual, and great documentation.
Evan
 
#6
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 :grin:
 
#7
Looks good, Question, How do you do you figure the offset for the tail stock.
 
#9
Looks good, Question, How do you do you figure the offset for the tail stock.
Hi kvt, thank you very much!:grin:

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
 
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#10
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:oops:. I was thinking going away from the op.
 
#11
Warning, be careful with tapers. Sometimes the double taper is stated, sometimes single taper. Sometimes it is inches per foot, sometimes taper per inch, sometimes decimal degrees, sometimes degrees, minutes, and seconds, sometimes diameter change for a given length, sometimes metric. The various Morse tapers do not all have the same angles. And more. It can go badly wrong if you don't stay on the same page with all the units, and pay attention. The instructions Ulma Doctor gave you for the MT3 are simple, useful, and easy to follow.
 
#12
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:oops:. I was thinking going away from the op.
Hi kvt,
i print up all kinds of charts and shop stuff and hang them in strategic places with thumb tacks or staples, as well as keep a binder in the shop.

believe me, adjusting out away from the op was the way i had it envisioned too, until i watched it being done! :grin:

Warning, be careful with tapers. Sometimes the double taper is stated, sometimes single taper. Sometimes it is inches per foot, sometimes taper per inch, sometimes decimal degrees, sometimes degrees, minutes, and seconds, sometimes diameter change for a given length, sometimes metric. The various Morse tapers do not all have the same angles. And more. It can go badly wrong if you don't stay on the same page with all the units, and pay attention. The instructions Ulma Doctor gave you for the MT3 are simple, useful, and easy to follow.
Thank you very much Bob :grin:
i agree 100%, having the taper in inches per foot is critical to using the formula i used.

if you get your math correct, the taper is not very difficult to reproduce- i hope anyone who reads this thread attempts to reproduce at a taper-
if only for fun! :grin:
 
#13
There's the minor matter of offseting the tailstock though. I would never be able to get it back to 'True'
 
#14
There's the minor matter of offseting the tailstock though. I would never be able to get it back to 'True'
sure you could!
you could reverse the process and dial Zero back in and go .176" the opposite direction.
then check with a test bar.
it's not difficult to do :grin:
 
#16
There's the minor matter of offseting the tailstock though. I would never be able to get it back to 'True'
Been thinking about that myself. What about drilling a shallow 1/8 hole in the joint between the top and bottom BEFORE offsetting it. Then to return to zero just align the top until a 1/8 pin fits in the hole.
 
#17
Been thinking about that myself. What about drilling a shallow 1/8 hole in the joint between the top and bottom BEFORE offsetting it. Then to return to zero just align the top until a 1/8 pin fits in the hole.
I think I would use a less permanent solution. With wear the adjustments change over time. An adjustable stop might be useful, and the setting could still be changed when needed.
 
#18
There's the minor matter of offseting the tailstock though. I would never be able to get it back to 'True'
If your lathe compound has enough travel? Cut the taper with your compound. And please don’t be concerned about re-aligning the tailstock. There are many good ideas on aligning the tailstock in the HM. It’s easy enough.
 
#19
[QUOTE="i centerdrilled both ends.[/QUOTE]
Did you use a center drill with radius? Or 60° conical type?
 
#21
I think I would use a less permanent solution. With wear the adjustments change over time. An adjustable stop might be useful, and the setting could still be changed when needed.
Bob, just curious as to what wear you are referring to.
If for any reason the TS zero position had changed over time, the hole could be drilled to the next largest size to 'record' its new position prior to being offset. The pin would only be used as a go/nogo gauge when returning the top back to its starting point so nothing would prevent the TS from subsequent fine tuning for other purposes.
I have not actually done this but logically it makes sense especially if a taper pin is used. A permanent style zero feature like this would be reassuring to me (I think :)).
 
#22
Everytime you slide the tailstock along the bed/ways it wears a little more. Everytime you put that drill chuck (that has run-out) into the tailstock quill, you get a new register. This is not a perfect world. Nature gave you a brain to smooth out those wrinkles in life…Dave
 
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#23
And nature gave us eyes to read. I asked Bob what wear HE was referring to. I can guess but would rather have him express his own thoughts.
Anyone who adjusts a TS every time they slide it along the ways is going to be very familiar with the procedure and would not show a normal hesitation as mentioned above.
 
#24
I may add if you Ck the offset with the size taper your cutting its pretty simple to be very accurate. In other words put a drill in the chuck and use an indicator to Ck for the right size end to end of the taper . 0 on the indicator . LATHES set up .
 
#25
I can't make out the dog, can you post a picture of of it if you mount it up again?
sorry for the delay, here is a picture of the drive dog.
it is a guide collar from a meat processing machine i modified to be a drive dog.
the bend in the shape is why it got scrapped, courtesy of a careless operator :black eye:
it's ugly, but as a drive dog it gets er' done just fine!

IMG_2593.jpg

and here is another for slightly larger mater, pictured next to the first one.
both are constructed from 100% aluminum scraps, except for the clamp screws- i went all out and paid for new hardware for both :grin big:
i just finished the construction of the 1.125" drive dog.
i won't have to turn down much stock on most items to put them between centers, and drive it with the dog!

IMG_2594.jpg

the top dog has a .970" ID, the lower dog has a 1.125" ID
 
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#26
Bob, just curious as to what wear you are referring to.
If for any reason the TS zero position had changed over time, the hole could be drilled to the next largest size to 'record' its new position prior to being offset. The pin would only be used as a go/nogo gauge when returning the top back to its starting point so nothing would prevent the TS from subsequent fine tuning for other purposes.
I have not actually done this but logically it makes sense especially if a taper pin is used. A permanent style zero feature like this would be reassuring to me (I think :)).
I wrote an answer to you, but I guess I forgot to send it.
I was referencing long term wear over time. Your idea of drilling to the next larger size would work. Doing that with a taper pin may not be so easy to be accurate. I was thinking about some sort of screw adjustable stop that could be locked with a jam nut or similar, and readjusted as necessary.
 
#27
Offsetting the TS to turn tapers and then returning it to its original position can be intimidating the first time. Much the way removing the gap piece in a gap bed lathe and then having to reinstall it can cause hesitation in some newbies.

During the time it takes to turn the taper, I doubt that any new wear occurs that needs to be accounted for so why make the operation more complicated than it has to be for a newbie?

Fine tuning the TS however should become familiar to a hobbyist not only because of long term wear but also when the job at hand requires some tweaking of the TS. Since the TS should be in an acceptable zero position before offsetting it to cut a taper, it makes sense to me to have a quick and ready index to make short work of returning it to the starting point. I don't trust my eyes enough to use the scale riveted to the TS that is provided for alignment.
 
#28
During the time it takes to turn the taper, I doubt that any new wear occurs that needs to be accounted for so why make the operation more complicated than it has to be for a newbie?
Indeed. When we offset the tail stock, it is wise to have an indicator on it, and to return it to where we started after the job. However, you might bump the indicator at some point before returning it to its original position and then need to use a test bar or similar to get it back where you want it. Just saying...
 
#29
Which is why the idea mentioned in posts 16 and 21 looks so interesting to me. No indicator or test bar is needed.
 
#30
I did some more work on the arbor yesterday...

i inserted the arbor into the MT3 spindle of my Hercus ARH 922 lathe for the finishing work.
i didn't need the drawbar for the machining operations as the arbor had great holding strength with a slightly forceful rapid insertion.


i parted the arbor a bit shorter

IMG_2595.jpg

then started the 1" and 7/8" steps
IMG_2596.jpg

i drilled and tapped the end for 3/8"- 16tpi x 1" socket head capscrew

IMG_2597.jpg

and then took a clean up skim cut of the OD

IMG_2599.jpg

i'll make the end cap in the next episode....
thanks for reading!
 
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