Thread: Drilling large hole over small hole or vice-versa

A very good idea Niki. I usually use a cross slider vice so a physical position marker should work with this also. I also encounter a similar problem where I need to remove the piece I am working on from the vice under the drill bit. It then becomes a problem of placing the piece back in the same position. An added complication is that sometimes these pieces are quite small and may be clamped in between the vice jaws. When possible I place pieces flush with the side edge of the vice which works but this is not always an option. However, it should still be possible to set up a physical locator/marker that reaches inside the vice .
Thanks

Thanks for the idea Niki. I will certainly set it up on my DP.

Interesting ideas there. I sometimes use a countersink bit to align an existing hole to the position of the drill chuck. Just lower the (conical) countersink bit into the existing hole and the workpiece self-aligns to it. Then remove the countersink bit and insert the drill bit. Don't get as much vertical flexibility as with your method though.

BTW: if you flip your 'zero clearance insert' upside-down you can get 4 uses out of it. If you make a square insert, you can rotate it 90 degrees, then flip it upside-down, and you get 8 uses.

Originally Posted by zenwood

BTW: if you flip your 'zero clearance insert' upside-down you can get 4 uses out of it. If you make a square insert, you can rotate it 90 degrees, then flip it upside-down, and you get 8 uses.

What a Cool idea Zen! I supposed if one could use a 3D square block one could get 12 uses.

Originally Posted by BobL

What a Cool idea Zen! I supposed if one could use a 3D square block one could get 12 uses.

Way above my head, here. Is a 3D square block what is commonly called a cube? And why would that allow 12 uses? Help!

Originally Posted by Frank&Earnest

Way above my head, here. Is a 3D square block what is commonly called a cube? And why would that allow 12 uses? Help!

2 holes in each face. 6 faces in the cube. Total is 12

Originally Posted by Frank&Earnest

Way above my head, here. Is a 3D square block what is commonly called a cube? And why would that allow 12 uses? Help!

Thanks Frank - "cube" is a far better word - must be an early senior's moment. A cube has 6 faces and one can use the top half of one face, then rotate and use the bottom half, then rotate to the other five faces and repeat.

Dang - JK beat me to it by a microsecond - 3 minutes actually!

Actually you could get 24 uses from a cube (4 per side x 6 sides)

Yes a cube would give you 6 x 4 = 24 uses, but would require a very deep hole to put it in

Thank you for the kind replies

Zenwood
I did try it but the sacrificial plate is located at the center-line and when I turned it upside-down, the hole location relative to the drill is almost un-changed.

I can turn the table to left or right so the drill will come over other location but than, I'll not be able to use the fence distance measuring rulers that are adjusted to the center-line (see pic)

Regards
niki
Attachment 46564

Thanks everybody - I was thinking 24, hence my confusion - McFly and Zenwood seem to concur. I am still lost about the purpose though, unless the aim is to achieve a higher level of accuracy. In my extremely amateurish way, I just drill all the small holes, change to the larger bit size (twist drill), present it to the small hole so it self-centers, clamp the piece and drill down to the desired depth. If really essential, a second pass with a forstner bit could be made to flatten the bottom of the recess, but I never bother in soft wood. I know, I am rough, please don't be too hard on me!

Originally Posted by Frank&Earnest

Thanks everybody - I was thinking 24, hence my confusion - McFly and Zenwood seem to concur. I am still lost about the purpose though, unless the aim is to achieve a higher level of accuracy. In my extremely amateurish way, I just drill all the small holes, change to the larger bit size (twist drill), present it to the small hole so it self-centers, clamp the piece and drill down to the desired depth. If really essential, a second pass with a forstner bit could be made to flatten the bottom of the recess, but I never bother in soft wood. I know, I am rough, please don't be too hard on me!

For 24 you'd have to have the cube placed offset so the centre line of the DP post and drill bit go through the centre of any quadrant on a cube face. In Niki's case his centre like goes down the middle so he would only get 12.

The reason for Niki's rig/idea is more applicable when first using any drill, and then using a larger forstner bit, or one forstner followed by another. That's why most people do this if possible the other way around ie use the bigger and then the smaller one, so it can centre on the inner centre point recess (although sometimes it's still quite hard to see).