Mill Drill Issue

[jamesemery728]

This is just a general question about a round column mill drill. When going from milling to drilling the length of the drill chuck is much longer than collets and requires raising the head for enough clearance. I know that this is one of the often mentioned drawbacks of a mill drill that once you raise or lower the head you have to realign everything again. The question is has anyone come up with a practical solution to this issue like a shorter drill chuck or some other innovative idea. I sometimes just put the drill in a collet if the collet and drill are matching sizes but this is not always the case. I have seen all the configurations that people have built that are designed to keep the head from rotating when you raise and the laser beam on the wall, but if anyone has any other creative ideas I would love to hear them.

 

[tel]

I have a bunch of short tooling, including a good selection of stub drills, bushed to 3/8" - actually made for my tailstock turret, but also very handy around the RF30.

 

[RICHARDDV]

something that works for me when i need more clearance when changing from a mill bit to drill bit is to eliminate the drill chuck altogether. i used a drill chuck taper adapter ( mt 2/ j 33 etc.) and center drilled it and threaded it to accept threaded stubby aircraft drills. all i need to do is pop the mill adapter out and install the drill adapter without disturbing the column setting richard

 

[Metal Butcher]

I have a round column mill/drill and have given up on the idea of finding a solution. I don't think there is a worth while fix for the problem. And I wish I could give you an answer to directly address the the heart of your post.

Locking the loose fitting gear rack to the column won't work, and if it did it would create a problem of its own by fixing the position of the head. I tried the laser idea and it was no where near what I could call accurate, simply a waste of time tying to make an accurate adjustment.

I reconfigure my machine from drilling to milling constantly. I simply use an edge finder and zero out my hand wheels on the edges of the work piece in the X-Y axis. It takes a few minutes to collet mount the edge finder and then switch it out for another collet to fit the end mill. I get accurate results using this method and with time it became a step that no-longer seems to be a big bother.

Now...cranking the head up and down, that's another story! :rant:

-MB

 

[gbritnell]

Hi James,
At the time I bought my mill drill there weren't many options for the home machinist in the way of milling machines. (1978) Over the years I have followed the Mill/Drill activities on Yahoo groups and threads started about this subject on other forums. Sadly I haven't read about any viable way of accurately moving the head up and down while maintaining position. The closest anyone has come is to mount an angle plate on the end of the table and when you are ready to move the head put a dial indicator against the plate then move it. With the laser method even if you're off .003 then you might as well pick up your position again. I have come to the realization that this is how it is so I just deal with it.
Nowadays there are so many different mills available for the home shop machinist that I don't know why anyone would buy a round column. With the bench top type mills that have the head moving up and down on a set of ways that problem should be eliminated. I have never asked the question about how accurate they are compared to a knee mill.
I have done thousands of jobs on my round column mill and it works fine. For the minute or so that it takes to relocate my position I hardly think about it any more, but please let me know if you find out something positive.
gbritnell

 

[kcmillin]

Give yourself more options for mounting tooling, and like Tel, get/make shorted tooling.

I use an ER32 collet chuck to allow me to get a milling bit lower, and still have room to put a drill bit in an R8 collet. I also have a 1/4" drill chuck with a straight shank, this is much shorter than a standard chuck and gives me yet more options. I rarely have issues with clearance, as long as I think ahead through all the steps.

But as MB says, it is not a time consuming process to reset the table, just a matter of minutes, it is something that all of us mill/drill owners have to deal with.

Kel

 

[kanvelchoudhary]

i believe the simplest idea is to use a mark with a scale around the column. with little consideration you will find that each time you increase the clearance their is a specific deviation which can be easily calibrated on the scale in terms of angle.
or u can simply go on with modified tools which can be used without drill chuck.

 

[aheg1220]

Makes some "collets" for your drills. Turn some blanks to fit in a collet, drill a hole through it with the drill bit you are using it for, then cut some slots in the "collet". Stick the drill bit in the "collet", put it in an actual collet for your mill, and make some chips....

 

[metalmad]

the idea about a clocked up angle plate one the end of the table sounds very good !!
Pete

 

[imagineering]

Someone, somewhere, perhaps on this site, used a Laser mounted on the Mill/Drill Head which then beamed to a Vertical Line Marked on the opposite Workshop Wall. IIRC he was claiming 100% accuracy within the limits of his Tooling.

 

[milotrain]

It might be possible (although not small, easy or convenient) to set up a second round column in the back of the mill and bind the mill head to a large bushing pack that travels up and down the second column, sort of like dual column height gauges.

 

[Maryak]

I have owned and operated a round column mill drill for some 8 yrs now. The only times I have encountered an alignment problem is when spotting and then drilling a larger hole, (one where the drill bit is considerably longer than the spotting drill). As long as you remember to set the column to the height for the larger drill before you do the alignment it's mostly a non issue.

When starting out, had I not been offered my Mill/Drill, 2nd hand with considerable tooling, at a bargain basement price. I would have opted for a small proper turret mill with a knee and a quill feed, (at the time they were available for just under $AU3K new and I had a job).

Just my 2 bob's worth.

Best Regards
Bob


https://www.machineryhouse.com.au/Products?stockCode=M160#

 

[Omnimill]

Another idea is to sell your Mill Drill to help finance a Dovetail Mill. Many folks seem to have done this and round column Mill Drills seem to sell pretty easy, at least over here. Just a thought.

Vic.

 

[Reed]

For the mills I have a set of drill bits (fraction, letter, and number) that are screw machine length.

It does 2 things for you, decrease the length of the drill and with less precise requirements it allows skipping the spot drill.

- Reed