Accuracy Of Hole Layout , Center Punch, Dividing Head

[visenfile]

Great information. Please keep it coming!

For auto noobs I should point out that just successful fitting of the new wheel studs through the wheel clearance holes is not so significant. What matters is that the angled wheel nuts nestle and torque correctly. You can easily see the seating area of these nuts if you look at the wheel. Any registration problems will by magnified be difficulty seating and torquing and can be dangerous due to work hardening and breaking of the studs. This is widely known and verboten. So I guess an attempt at drilling such holes could be evaluated with some blue marker on the wheel counter sunk areas and nuts, not to mention "feel" as the nuts are drawn up, and they must be perfect, no?

I have tried movement of punch marks and it is a good tool even though sometimes the dimple can be distorted and confuse the drill tip of where to enter.
A final question I forgot earlier. When looking at dimensions of drill bushings I did not see clearance call outs for the drill dia and the bushing ID. Isn't this one of the main values of the hardened bushing, i.e., keeping the drill from wandering? Thanks

 

[stupoty]

Has anyone here ever used toolmakers buttons or discs to layout holes?
Please note "used" them vs read about them or saw a video?
If so, I've only done the latter, and am curious about your perspective and experience vs other methods.

Daryl
MN

I've been trying to make myself use them recently, I found them really handy, I wanted to make two holes in two parts with very good relative location. I used gauge block stacks under the horizontal and vertical side to set them. I think with more practice they could be a bit quicker to use as well.

I've got some that I have made, I actually made them from a part that went wrong a better surface finish would make them better.

IMG_2338_sml

• stupoty
• Feb 14, 2016

Button Attached to work piece whilst it's being indicated.

IMG_2339_sml

• stupoty
• Feb 14, 2016

Quick spin with it still attached for a visual look.

Stuart

 

[stupoty]

If you have a surface plate and height gauge it's possible to layout the holes in a square box instead of a circle. Then with a plate with the required hole size ( reamed preferably ) clamped over the "box" it's possible to adjust the hole plate so that the "box" lines can be made ( and seen) equal around the hole. The hole can then be drilled through the hole plate. The underside of the hole plate should have no chamfers or burrs and the hole should be "clean all the way through. Ideally the hole plate should be hardened and ground on the under surface. If the desired hole is bigger than the hole , the plate may be used as a"spotting" plate and removed for drilling the correct hole size. With this method placing holes in the order of .003" is possible. This method is commonly called " boxing-in holes". Using toolmaker's buttons or discs is a bit more accurate but all of these methods is more accurate than center punching the hole positions. Most pre DRO toolmakers had a selection of hardened "boxing hole plates" and discs.

Boxing in the holes, interesting sounding technique I think I will do some googling and reading.

Stuart