CXA holder for MT3 to power feed drills

[cathead]

This was a big project for one day but managed to finish it up before supper. I have a large chunk of steel that
with one cut gave me the rough dimensions of the holder. After truing it up on all 6 sides, I proceeded to mill
out the dovetail. Once that was done, a 5/16 inch drill was passed though the holder, then a 3/4 inch, then a
slightly larger bit entering into the hole one inch.
This was my starting point, a big chunk of steel in my home made band saw.


Here it is after some machining including a Morse#3 taper hole.


I used the lathe to power the #3Morse tapered reamer.


Here is the #3 Morse tapered CXA style holder ready for power feed drilling. I don't have a job for it at the moment but if I
have to do a lot of drilling of large holes in thick material, it will come in handy.

 

[Ulma Doctor]

Very nice, Burt!

 

[cathead]

Out of curiosity, I installed the drill chuck with a nice straight piece of steel rod to see if the new CXA5(home made)
was level with the bed of the lathe. I'm reading a few thousandths drop over about 5 inches as I head for the
drill chuck. Then I checked the carriage against the bed and found pretty close to the same readings.
I think that would mean my new holder is quite true. I also tried a DTM MT3 holder and got about the same
results. Then I went to the old "Springfield" 1920s lathe and did the same tests there. The drop was a little
less on that with both the CXA and the DTM. So it looks like the new CXA5(home made) will be fine for general
use. The carriage isn't moved much in reaming the Morse taper so it all makes sense to me now. I wasn't too much
worried about the "reading drop" after I did my testing. Drilling isn't a precision operation anyway so all in all happy
with the results. I'm pretty sure the steel used was hardenable but thinking it might be better left as is in case
I decide to tweak on it a little more some day. I may also get some readings using a granite surface plate and
see how those readings compare just for fun.

 

[Shotgun]

I'm inspired.
I've got a big boring bar holder that's doing nothing, because I have no boring bars anywhere near 3/4". You're setup to get the taper should let me get a similar holder in just a few minutes, and it'll be useful all over the place.

It'll also enable me to use it for boring bars I have. Just put them in the drill chuck.

 

[cathead]

I'm inspired.
I've got a big boring bar holder that's doing nothing, because I have no boring bars anywhere near 3/4". You're setup to get the taper should let me get a similar holder in just a few minutes, and it'll be useful all over the place.

It'll also enable me to use it for boring bars I have. Just put them in the drill chuck.

Just a note for you: The MT3 reamer I used is a finishing reamer and worked quite well for the whole operation.
One can drill down partly with the appropriate sized bit from the wide end to get a rough taper,
then finish up. You need to position the tool holder carefully at the proper height in the process.
Also be sure to check that the holder isn't so hard that you can't ream it.

 

[mmcmdl]

Jeeez . Day late and a $ short for me as always . I'm running a Dorian up to Cabin Fever tomorrow . Nice job on yours cathead .