Hole spacing

[Larry Blanchard]

No math required - just arithmetic :-).

If you want a 1/4" border at each end, the center of each of the end holes has to be 5/8" (1/4" + 3/8") from its end.

That leaves 4 3/4" between those 2 holes. In that space you have to put

4 more holes with 5 spaces between holes. 4 3/4" divided by 5 gives a spacing of just over 15/16" (4.75 / 5 = 0.95).

Since that doesn't come out even, you need to take the slop (1/16") and redistribute it to each end. So instead of the centers of the end holes being 5/8" from the end, they should be 21/32" from the end.

Or you could just ignore the slop and have one space be 1/16" wider than the others :-).

I hope you're aware that those holes are only going to have 3/16" of wood between each pair.

[Larry Blanchard]

I bought some wood taps and dies once to make some wooden vise screws. I used a 1" dowel (yes it was 1") for the screw. I cut threads in it and the hole to receive it with no problem. But the screw wouldn't fit.

Turns out the tap and die were 25mm, not 1" (25.4). So yes, it can make a difference.

I got a fresh dowel and turned it down to 25mm or a little less.

[Doug Miller]

No, but it sure makes the calculations a LOT easier. Reduces the risk of error, too, because you're always adding either integers or decimals -- not mixed fractions.

[Doug Miller]

Totally different context. When you're talking about fitting a shaft into a hole, tolerances of 0.005" or less can be critical. When you're talking about a border around something, the difference between 1/4" and 6mm is unlikely to be important to anyone, or indeed even noticeable.

[Steve]

Here's a way to do it by only actually measuring two points. The rest is mechaincal division.

SInce you're spacing 3/4' holes within 5 1/2 inches, you've already defined a 1/4" border on each end. The radius of your hole is 3/8". Thus, the centerpoint of each outer hole is 5/8" from the edge. Mark those points.

Now, draw a line though each point, parallel to the ends of the board. Since you're marking the center points of 4 holes and using the center point of the other outer hole as your terminus, choose a number easily divisible by five (like, oh, 7.5 or 10). Lay the zero point of your ruler on one line. Swing the ruler until your chosen number lies on the other line you've already drawn.

Then, just mark the correct divisions (1 1/2, 3... or 2,4, 6...) and you've marked the center points for the other four holes. Draw lines through those points and parallel to the ends crossing your center line, and you're done.

You can, of course, tell people how brutal the math was in calculating those points... but if you wanted to add the same dimension (x2) outside your row of holes as between each hole, the math is more than I want to deal with.

[RicodJour]

Equal divisions on a line using a ruler held at an angle. No calculation required.

calculators: 's an app for that:

[John]

You don't need math:

Set the ruler (or tape measure) on a diagonal across the piece so that the 6" mark is even with one end the 0" is on the other end. Mark off 1" increments on the diagonal. You can also use even multiples of the spaces needed, say 30" and mark off every 2" for 15 spaces.

John

[John]

Make that set the 1" mark at the first hole and the 6" mark at the last hole and the technique will count the number of holes for you.

John

[Leon]

Some times the keys on my key board trade places. '~)

[Leon]

Spread sheet! I dont need no stinking Spread sheet. LOL I took 6" -1/2" for both borders - 4 1/2" for the holes and ended up with 1. Divided 1 by the number of spaces, 7, and got .014285" for the spaces, then I drew it. '~0

[Leon]

Actually a little less, 5/32"

[Leon]

And you thought this math problem was confusing was fore you asked? ;~)

[Leon]

Ah hum.... and you thought this math problem was confusing before you asked...

[HeyBub]

Sure. Tell that to the group that engineered the Hubble Space Telescope where confusion over metric/proper measurements resulting in the launch of an almost worthless instrument.

And consider these two standards:

"Meter = 1/10,000,000 of the distance between the North Pole and the Equator measured along the Prime Meridian." (Alternative definition: "1,650,763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum.")

vs

"A pint's a pound the world around."

Now I ask you, which is more practical for your average woodworker?

[Han]

"HeyBub" wrote in news:uLednZB_UfsmZM3TnZ2dnUVZ [e-mail]:

Metric rules. Just like US measurements, if you grew up using one, it takes a while to get used to the other. STill good to know both, since otherwise how would you know why plywood comes in sheets of 244 x 122 cm ...

[Pin]

6" - 1/2" = 5.50" /7 = .7857 inch = 1.9956 cm so 2 cm spacing then drill each hole.

or 25/32 = .78125 closest to .7857

Pin

[Pin]

What is a.b.p.woodworking or a.b.o.woodworking? I look for binaries groups but see none

Pin

[Dave]

alt.binaries.pictures.woodworking

[Pin]

Thank you

[RicodJour]

I'd rather have the pint.

R