• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • PLEASE: Read the FORUM RULES BEFORE registering!

Fun With Unknownium, a MT2 Tailstock Center Drill Holder-From Scratch

Ulma Doctor

Infinitely Curious
Active Member
Joined
Feb 2, 2013
Messages
4,294
Likes
3,483
#1
I use my Shenwai SW900B lathe to do a lot of my projects.

photo 3.jpg

this time i wanted to make a full-time tailstock center drill holder,
the problem was that i never cut a morse taper before on a lathe.
i doubted my ability to make a concentric tool with a MT2 taper that actually worked.
that had to change.
if i was to succeed, i would need to rise to my challenge and go and do something about it :grin:

after going through a what seemed like a semester of virtual trigonometry and watching hours upon hours of videos
i came across fellow member, @Halligan142 's videos on cutting a MT2 taper
here is a link to the video that inspired my confidence
a well made production , it's for another purpose i'll leave for his description.
i stole an idea from him and wanted to give the credit where it was due.
enjoy his video!


after watching the video,
i got up and went directly to my garage shop
i had a leftover 7" long X 1" diameter piece of unknownium, left from a project completed yesterday
here was the shaft before the 2 projects...

FullSizeRender_5.jpg

Here are the Cliff's Notes , using the formula Halligan142 used in his video:

tailstock offset=(Length of Part X Taper per foot)/24

in other words, the offset for the tailstock is determined by the length of stock multiplied by the taper in inches per foot.
you then divide the product of the afore by 24 to find the offset you will introduce.

in my case, i made my unknonium 7.00" long
my arithmetic worked out like this...
7"long x .5994= 4.1958
4.1958/24=.1748"
so my tailstock offset should be .1748"

using a shop made test bar, i indicated the tailstock straight as a verified reference point before the offset
i put a dial indicator on my apron and measured the tailstock's creep towards me as i adjusted the tailstock offset screws.
after rounding up slightly, i dialed in .1750" offset.
i used the threading feeds to hog off most of the material with a HSS Roughing grind at .020"passes.
when i came down to getting within about .030" of what i figured was final dimension,
i switched to TT style carbide inserts and slowed the feedrate to finest feed rate possible
the cuts came out silky smooth!!!! :grin:



FullSizeRender_1_6.jpg
IMG_2846.JPG

here is a picture of the first fit up in the tailstock
still need 2 small .001" passes to get right

FullSizeRender_4_2.jpg

after working the newly formed MT2 arbor with scotchbrite and 400 grit wet/dry sandpaper
i got this as a result...

if you really look-you can faintly see the blue on my shop made arbor
it covers a very nice contact area, that i'm proud to have constructed

FullSizeRender_3_2.jpg

eager to compare my newly crafted joy,
i compared the MT2 taper my normally used live center sets on :grin:

FullSizeRender_2_2.jpg

maybe you can tell by the poor picture,
but my new taper had about 30% more contact area than the old MT2 taper on my live center, that i thought was very accurate

i still need to part the excess material off the arbor,
but that will be left for act 2

same bat time, same bat channel!!!
 
Last edited:

rgray

Active User
H-M Supporter-Premium Member
Joined
Nov 26, 2012
Messages
809
Likes
353
#2
Nice!!
I'm gonna keep that formula handy. Looks like it will be a good one to know.
 

richl

Active User
Active Member
Joined
Mar 2, 2013
Messages
700
Likes
470
#4
Thanks Mike, that was a big gray area for me also, I was not looking forward to digging thru a couple volumes of machinist manuals to get that info. Very nice work on your walk thru also.
As for Mr. Halligan, he sure takes a beating in his video comments. His way of doing things may appear rough to a pure machinist, but coming from the construction world myself, I am sure my way of doing things are a touch more crude:encourage:
 

Ulma Doctor

Infinitely Curious
Active Member
Joined
Feb 2, 2013
Messages
4,294
Likes
3,483
#5
Thanks Mike, that was a big gray area for me also, I was not looking forward to digging thru a couple volumes of machinist manuals to get that info. Very nice work on your walk thru also.
As for Mr. Halligan, he sure takes a beating in his video comments. His way of doing things may appear rough to a pure machinist, but coming from the construction world myself, I am sure my way of doing things are a touch more crude:encourage:
Hi richl,
thank you for your kind words.
this was a dragon i had to slay! i'm glad i did!!!
i agree, a lot of people bash people that DO things, instead of TALKING and armchair quarterbacking.

i'm of the mind that if a part comes out as good or better than an original, who cares what method you took to get there.
(unless you are doing it for money, then the shortest time is the best way)
making things all complicated first, doesn't assure precise results.
i find in real life, that the simpler you make a problem, the easier the job becomes.
 

Ulma Doctor

Infinitely Curious
Active Member
Joined
Feb 2, 2013
Messages
4,294
Likes
3,483
#6
Meanwhile, Back in Gotham City.....

i got a few moments alone in the shop with my machines and tools.
i parted off the the center drill arbor

IMG_2852.JPG
using my Hercus ARH lathe, i used a 4 jaw chuck and indicated and center drilled the arbor
i then drilled the arbor to 9/32"diameter and 1.15" deep.
then bored the arbor with a tiny cheap carbide boring bar to about .300"diameter
i then used a chucking reamer to finish the bore to .312" to accept my favorite #4 center drills with a snug fit.

i then cross drilled the arbor to accept a 5/16-18 x 1/4'" anti vibration set screw

IMG_2853.JPG
and made final assembly.

IMG_2854.JPG

IMG_2855.JPG

and the money shot, the finished tool is installed and ready for work!!!

IMG_2856.JPG

thanks to Halligan142 for the great tailstock offset method and formula to turn the MT2 taper.
my creation may not have been as easy if it were not for his inspiration!

as always, thanks for reading!!!
 

Silverbullet

Active Member
Active Member
Joined
May 4, 2015
Messages
2,347
Likes
1,055
#7
Now you can make tapping and die holders on a slider into the tailstock . All kinds of arbors needed for the lathe and drill press even mills . I see er32 collet chucks in your future.
 

richl

Active User
Active Member
Joined
Mar 2, 2013
Messages
700
Likes
470
#9
As soon as I get a chance for some playtime that's what I want to do with my 2" boring holder.
It really does open up the possibility of a bunch of tooling for the lathe, and 30 tapers for the mill:encourage:
 

Ulma Doctor

Infinitely Curious
Active Member
Joined
Feb 2, 2013
Messages
4,294
Likes
3,483
#10
As soon as I get a chance for some playtime that's what I want to do with my 2" boring holder.
It really does open up the possibility of a bunch of tooling for the lathe, and 30 tapers for the mill:encourage:
thanks for commenting richl,
i hope to see your creations!
 
Container Above bottom breadcrumb