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View Full Version : Lathe: drilling under power feed ?



TR
02-28-2015, 08:56 PM
I see these tools holders for sale. Are they useful ? Rather than using the tail stock for drilling, is this a useful alternative using the tool post ?
What do the experts think ?
Thanks in advance,
Tom

http://i663.photobucket.com/albums/uu354/topari/dorian_cxa_drill_chuck_zpsznmstt8t.jpg (http://s663.photobucket.com/user/topari/media/dorian_cxa_drill_chuck_zpsznmstt8t.jpg.html)

RichTes
02-28-2015, 09:21 PM
I'm pretty sure the tailstock is centered. How accurately can you center one of these. Wouldn't the bit be likely to snap if not on?

Rich

Toolguy
02-28-2015, 09:27 PM
You can drill with power feed with those, as it will be on the carriage. Personally I would just feed with the handwheel or start with a slow feedrate and work up to where it's making a nice looking chip. It's easy to overpower that and twist the toolpost, maybe ruining the hole and snapping off the drill in a worst case scenario. I think they can be useful if used wisely. There is a similar item that holds 5C collets too. I have been threatening to get one of each someday when I get rich and infamous.

tmc_31
02-28-2015, 09:33 PM
Tom,

I am certainly no expert but I have used a similar tool holder to drill on my lathe under power. I was pushing a 7/8" drill bit with a MT3 shank through a 1" thick 3" dia circular blank. I could also put my MT3 drill chuck in this tool post. I started using the tail stock but soon tired of that and decided to drill under power using the carriage. One thing I found is that these tool holders drill off center to the line of thrust and there is a tendency to spin the tool post under heavy feed. My tool post came with a pin so that I could pin it to the compound and using that solved my problem. I wound up drilling about 65 of these blanks and it worked pretty well.

One of my future projects is to build a tool block that will bolt directly to my cross slide in place of the compound. The block will have a MT3 hole in it situated so that the drill chuck or MT3 drill bit will be aligned with the center line of the lathe, not offset with the center line like the tool holder you are showing.

All in all, I consider the MT3 tool holder a worthwhile purchase for me.

Here is my setup
http://i663.photobucket.com/albums/uu351/tmc_31/IMG_4666.jpg (http://s663.photobucket.com/user/tmc_31/media/IMG_4666.jpg.html)

All the best,

Tim

Rich Carlstedt
02-28-2015, 09:42 PM
Centering is pretty easy.
First, Once your height is set and locked with the thumb wheel , your Z axis is done.
Set the tool post square to the chuck and then install the holder.
Have a dead center (or live ) in the tail-stock and run the center up against the tool holder.
It has a 60 degree countersink inline with the drill chuck center on the backside (right) . So the tail-stock pushed into it will tell you when you are OK with X axis centering.
If you have a DRO, make a note of position. If not, then you need to know where your backlash is for repeat operation.

This tool really shines when doing repeat drilling and your tail-stock barrel is shorter than drilling depth, like say you are drilling 6 bushings 3 inches long and your tailstock quill is 2 inches and you must feed in then retract, and then move the tailstock in and reclamp and then proceed .
A pain in the butt.
It also is great for deep holes with long drills AND retract AND feed is much faster using the carriage handwheel.
It is nice for double drilling.
Use the tail-stock for a small pilot drill, then retract the tail-stock and "drop in" the tool and make the second larger hole under power ....don't move the cross-slide !..it's already set earlier.

Rich
You can tell i have one !

3illmesmart
02-28-2015, 09:42 PM
I used to run a Dean Smith & Grace that had a drill taper attachment on the crossslide. It had a 1/2 feed lever to drill under power. I would think the item you show is for use by hand power, not feed power, unless you have a very low feed rate setting.

TR
02-28-2015, 10:17 PM
Here I am in sunny Melbourne Australia, my mouth wired shut after a dental procedure went bad, stuck in my study and I read these excellent replies. Except I cannot smile. Thank you.

Rich Carlstedt
02-28-2015, 10:55 PM
Your welcome ...and get well quick !

Rich

oxford
02-28-2015, 11:16 PM
You could always wrap a chain from the carriage to the tailstock and have power feed drilling.

Black Forest
03-01-2015, 01:44 AM
My lathe has a provision to tow the tailstock with the cross slide but the glass scale is in the way now so I can't use it.

dian
03-01-2015, 05:06 AM
http://www.practicalmachinist.com/vb/general/pro-s-con-s-drilling-using-carriage-lathe-285689/

boslab
03-01-2015, 05:27 AM
As has been mentioned the DSG lathe has a power tailstock, nice, but you notice the hole finish is much better,

Carm
03-01-2015, 06:54 AM
Make your own block with the bore centered on the dovetail facing the chuck to avoid the above mentioned off axis leverage. Scrape in the toolpost/slide faces so load is spread maximally.
Make a plug to fit the bore with a concentric collar so the face can be trammed and the shoulder swept.

Lew Hartswick
03-01-2015, 10:02 AM
Doesn't make a lot of sense to me. If the hole is any more than about 1 or 2 bit diameters it only makes clearing the flutes about impossible. Many of the projects we do require
depths of 3 or 4 inches with 1/2 and 3/4 drills so using the tailstock ram and the carriage as a "re-setable" stop to make clearing and re-lubing so easy.
...lew...

tmc_31
03-01-2015, 10:38 AM
Hey lew,

you mean clearing the flutes like this:)

http://i663.photobucket.com/albums/uu351/tmc_31/IMG_4669.jpg (http://s663.photobucket.com/user/tmc_31/media/IMG_4669.jpg.html)

Tim

Mark Rand
03-01-2015, 01:16 PM
I've used the Multifix equivalent MT2 holder on my HLV for repeat drilling several hundred holes on a little job. It was handy to have a carriage stop and a dead-length 5C collet in order to get all the holes the right depth. Didn't need the power feed because the holes weren't that big, but it was less tiring than turning the tailstock dial round and round.

bborr01
03-01-2015, 02:18 PM
You can also use a drill chuck mounted in a boring bar holder if you have a drill chuck with a straight shank. Make sure you tighten the toolpost down good or it will want to spin on you.

Brian

Juiceclone
03-01-2015, 09:54 PM
I have a Jacobs chuck with a straight 3/4 " shaft that fits my AXA boring toolholder perfectly. I've only used a few times, but it worked well enough.(did not use power feed) Not as quick or handy as the tailstock but no real problem adjusting and centering it. Interesting/crazy enough, if you orient one of the cutting edges in the chuck horizontal like a boring tool, after you drill the hole, you can use the thing to make the hole larger just as if it was a boring bar!...I did mention crazy didn't I...

andywander
03-01-2015, 10:57 PM
.....Once your height is set and locked with the thumb wheel , your Z axis is done.....

Tool height on a lathe is adjusted in the Y axis, not Z....