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form_change
02-22-2011, 06:41 AM
Occasionally I want to cross drill round parts in the drill press. Usually I do this by positioning the part in a vice, putting a drill bit in the chuck and seeing if a pinched 6" rule is parallel to the table.
It works, but can be a bit iffy if the light isn't good, I'm in a hurry, the drill flexes a bit, the material is not square in the vice, the table hasn't been trammed and so on...
Anyone have any better ideas? For the sake of discussion, assume say a 5/32 drill and a 5/8 piece of rod (if you need to).
I've seen things that look like an inverted "Y" that pivot at the junction and are mounted in the drill chuck. Anyone use one of those?

Michael

PeteF
02-22-2011, 07:16 AM
Yes I just bought one of those "inverted Y" things from CDCO, but have only had a chance to use it on one job. The quality is A1-crappoli, nevertheless it actually seems to work pretty well. I'm sitting here and can't for the life of me even recall what the job was ... well putting a round hole in a round bar obviously, but quite why I wanted to do that at the time I can't recall. But I remember checking out the Y feed on the drill press and being surprised at how sensitive the little arm on the "Y" was to feed movements.

If you're after a super accurate, must be spot on method, you're probably better off looking elsewhere. However for a very quick and easy method it seemed to work just fine, and I couldn't complain about the price!!!

Pete

drmico60
02-22-2011, 08:17 AM
Occasionally I want to cross drill round parts in the drill press. Usually I do this by positioning the part in a vice, putting a drill bit in the chuck and seeing if a pinched 6" rule is parallel to the table.
It works, but can be a bit iffy if the light isn't good, I'm in a hurry, the drill flexes a bit, the material is not square in the vice, the table hasn't been trammed and so on...
Anyone have any better ideas? For the sake of discussion, assume say a 5/32 drill and a 5/8 piece of rod (if you need to).
I've seen things that look like an inverted "Y" that pivot at the junction and are mounted in the drill chuck. Anyone use one of those?

Michael
The problem with your method is that the point at which the ruler is level depends a little on the position of the drill. If you rotate the drill the ruler will deflect a little. It is much better to use a point. For accurate work I put an MT2 dead centre in the mill/drill and then use the ruler method. This is much more accurate than using just a drill bit. Also beware of rulers with engraved surfaces rather than etched surfaces as this can cause an error with the method.
For less accurate work I have a 6 mm rod with 60 degree point that can be put in the drill chuck.
Mike

Ian B
02-22-2011, 08:44 AM
Take a short piece of your 5/8" round bar, drill it through 5/32" lengthwise in the lathe. Sit this in the drill vice jaws on top of the 5/8" bar you want to cross drill, use it as a guide bush. It'll get you pretty close, and stop the drill from wandering.

Ian

Lew Hartswick
02-22-2011, 10:03 AM
Hold the peice in a X - Y table vise and use an edgefinder. :-)
...lew...

J Tiers
02-22-2011, 10:04 AM
You can make a "V" block with a hole accurately drilled through at the point of the V. Hole of a suitable pilot drill size.

if accurately made, it will let you put on-center holes in round items of a range of sizes almost without thought.

You can also make the hole larger and bush it with jig bushes or shop made ones for the common size drills use for pins etc......

fciron
02-22-2011, 10:26 AM
I have a shelf milled in my drill press vise jaws about 3/4" below the top. These act like parallels to hold things level and near the top of the vise so they are accessible. Depending how fussy I feel, sometimes I just hold it in a busted up old V-block I found. (It's rusty and had been drilled into a couple of times before I got it, so no worries.)

I center-punch my mark and try to get the punch mark centered between the vise jaws, then bring the drill down until it just starts cutting. Raise up the bit and look at the cut mark, if you're not on center the mark will be asymmetrical. Rotate the workpiece and peck with the drill again. When the mark looks good, drill on through. Not super-precision, it's sufficient to create tidy looking cross holes for cotter pins and such.

If I am paranoid or need high precision I use this jig in my lathe.

http://www.youtube.com/watch?v=eVgZol6Mfvo

metalmagpie
02-22-2011, 10:54 AM
I have one of those inverted Y thingies. Bought it from J&L back in the mid-90s and have used it many times. I think it's "good enough".

There are really two problems. One is centering the piece under the spindle axis, which is where the inverted Y comes in. The other is keeping a drill bit from wandering on the curved surface. Things you can try are using a short stiff bit (center drill if needs be) or milling/filing a small flat and then center drilling.

metalmagpie

ZINOM
02-22-2011, 11:09 AM
I use a method similar to the OP, only I use a piece of 5/16" drill rod with a good point ground on the end instead of a drill bit (which would a be less than perfect contact point of reference) and a 4" piece of 18 or 20 ga feeler gage stock.

Gets me almost dead-on 99% of the time and that's great for what I'm using it for....if I needed more accuracy I'd use an edgefinder.

Other times I'll eyeball a "sticky pin" or similar "pointer" with the center of the stock as viewed from the end (After facing a part I can see the center point with a magnifier) and then raise the pointer and dial in the other axis.

*Disclaimer* I may have the least experience and also need the least accuracy so factor that into my reply

John

the kid
02-23-2011, 05:05 AM
get a crotch center and do it on the lathe, easier then setting up in a dp or a mill and it will be strait and on center

Rosco-P
02-23-2011, 10:27 AM
Here's a commercial version of the Vee block with drill bushing plate: http://www.heinrichco.com/drill_jig_hand-op.htm

Juergenwt
02-23-2011, 03:55 PM
There is another problem with this method. Just how do you put in a center punch?
I use a V-block with a bushing for a small drill. The bushing is on center both ways "V" and length. Now I know the distance from the side (end) of my V-block I can mount a stop at the end and use Gage blocks to set the correct distance -
or I can measure the length sticking out and add 1/2 of the V-block length. Drill the pilot hole , turn V-block over and open up with desired dia.. The center bushing has a big body and is recessed enough so I can drill all the way thru.
For more accuracy I use my edge finder and vert. mill..

deltap
02-23-2011, 05:30 PM
This works if the part is not larger than drill chuck capacity or too long. Chuck part to be cross drilled in drill chuck. Clamp vise to lower end. Clamp vise to table. Vise is now centered for that dia part. Remove part from drill chuck and clamp horizontally in vise. Start with center drill. Drill to size. If I need more accuracy I use the mill.

Forestgnome
02-23-2011, 07:40 PM
This is the method I've used quite a few times: Blue the area where you're going to drill. Load the drill bit and bring it down to just touching the surface of the piece. Then move the piece (X-Y table) back and forth under the bit perpendicular to the axis of the piece. The drill bit will scratch the bluing, with the middle of the scratch at the center of the piece. Then I rotate the bit so the point is parallel to my line of sight, and I center it over the scratch by eyeballing. Ready to go.

Oldbrock
02-23-2011, 08:13 PM
Ian B. I like it, never thought of it for 60+ years, should have though. Best home made drill jig. Peter