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Forum topic by Winters45 posted 04-30-2016 02:35 AM 623 views 2 times favorited 11 replies Add to Favorites Watch
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Winters45

6 posts in 369 days


04-30-2016 02:35 AM

Topic tags/keywords: question

I’m trying to drill holes that are exatly perpendicular to my stock. As you can see in the picture, when i insert a shaft in the hole with no play, we can see that the hole is not perfectly perpendicular. I’ve tried to drill many holes at the same place that are progressively larger and rotating the piece as i’m drilling. I have also made sure that my drill bit is perpendicular to my table and that my piece of wood is square. And i think i have a decent drill press. Maybe i need better drill bits?

Maybe i’m asking too much and it is imposible to be that precise with wood, but any advise is welcome.


11 replies so far

View conifur's profile

conifur

955 posts in 612 days


#1 posted 04-30-2016 03:02 AM

What are you drilling into? wood? a good brad point bit is what you need. By your pic, and maybe it is the lighting, it does not look square/90, it looks tight at the base but I see light above, about 1 out of square.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View distrbd's profile

distrbd

2227 posts in 1907 days


#2 posted 04-30-2016 03:19 AM

Here’s Jack Forsberg(from a canadian ww site) showing you how to set up your drill press table :
https://www.youtube.com/watch?v=0og-beb4rg0

-- Ken from Ontario, Canada

View DrDirt's profile

DrDirt

4167 posts in 3203 days


#3 posted 04-30-2016 03:22 AM

Since you want to drill straight wth a hand drill.

First get a block of wood ~ 6/4 thick. Drill a ‘perfect vertical’ hole on the drill press.

Then use using a brad point bit the same diameter, put the point where you want the hold and hold the block in place.

THe block will ensure you go in straight

-- 'Political correctness is fascism pretending to be manners' ~George Carlin

View JBrow's profile

JBrow

817 posts in 381 days


#4 posted 04-30-2016 04:04 AM

Winters45,

I am not sure what could cause a perfectly aligned drill press to drill non-perpendicular holes. Some pure guesses are the drill bit is flexing as it drives into the wood, the drill press column is flexing (unlikely but possible), or the bit is wondering as it drills. Using a sharp bit and slow feed rate could reduce any flex, if any of my guesses are correct. And I agree, a Brad point bit or Forstner bit would help keep the bit from wondering.

I assume that the table was found perpendicular to the drill bit by using an engineer’s square set on the table and against a drill bit or true rod. This method of determining square may have enough undetectable imprecision to lead one to believe that a non-square hole problem is attributable to something other than alignment. Another method could be tried, which measures directly whether the table is perpendicular to the bit. The direct measurement method eliminates any undetected errors that may exist in the engineer’s square, steel rod, and any other things used to check for square.

This could be done with a thick block of wood (2-1/2” minimum), perhaps 12” long (the longer the better) that sets absolutely flat on the drill press table. Drill a hole deep with a ½” diameter bit into the block of wood at one end while keeping the wood firmly flat on the drill press table using a slow feed rate. Once the hole is drilled, turn off the drill press while the drill bit remains in the just drilled hole. When the bit has stopped spinning, raise the bit with block of wood still engaged on the bit just enough so the drill bit and block of wood can be rotated together on the bit by 180 degrees. In this position, lower the drill bit and the block of wood until the block of wood contacts the table. Any daylight under the block of wood, between the block of wood and the table reveals the table and bit are out of square. Then, spinning the bit and block of wood together 90 degrees checks the front to back alignment.

Jack Forsberg’s method also looks like pretty good way to check for/confirm square. However the table must be flat and smooth, at least wherever the dial indicator measurements are taken.

View conifur's profile

conifur

955 posts in 612 days


#5 posted 04-30-2016 04:08 AM



Winters45,

I am not sure what could cause a perfectly aligned drill press to drill non-perpendicular holes. Some pure guesses are the drill bit is flexing as it drives into the wood, the drill press column is flexing (unlikely but possible), or the bit is wondering as it drills. Using a sharp bit and slow feed rate could reduce any flex, if any of my guesses are correct. And I agree, a Brad point bit or Forstner bit would help keep the bit from wondering.

I assume that the table was found perpendicular to the drill bit by using an engineer’s square set on the table and against a drill bit or true rod. This method of determining square may have enough undetectable imprecision to lead one to believe that a non-square hole problem is attributable to something other than alignment. Another method could be tried, which measures directly whether the table is perpendicular to the bit. The direct measurement method eliminates any undetected errors that may exist in the engineer’s square, steel rod, and any other things used to check for square.

This could be done with a thick block of wood (2-1/2” minimum), perhaps 12” long (the longer the better) that sets absolutely flat on the drill press table. Drill a hole deep with a ½” diameter bit into the block of wood at one end while keeping the wood firmly flat on the drill press table using a slow feed rate. Once the hole is drilled, turn off the drill press while the drill bit remains in the just drilled hole. When the bit has stopped spinning, raise the bit with block of wood still engaged on the bit just enough so the drill bit and block of wood can be rotated together on the bit by 180 degrees. In this position, lower the drill bit and the block of wood until the block of wood contacts the table. Any daylight under the block of wood, between the block of wood and the table reveals the table and bit are out of square. Then, spinning the bit and block of wood together 90 degrees checks the front to back alignment.

Jack Forsberg s method also looks like pretty good way to check for/confirm square. However the table must be flat and smooth, at least wherever the dial indicator measurements are taken.

- JBrow


-- Knowledge and experience equals Wisdom, Michael Frankowski

View conifur's profile

conifur

955 posts in 612 days


#6 posted 04-30-2016 04:12 AM


Winters45,

I am not sure what could cause a perfectly aligned drill press to drill non-perpendicular holes. Some pure guesses are the drill bit is flexing as it drives into the wood, the drill press column is flexing (unlikely but possible), or the bit is wondering as it drills. Using a sharp bit and slow feed rate could reduce any flex, if any of my guesses are correct. And I agree, a Brad point bit or Forstner bit would help keep the bit from wondering.

I assume that the table was found perpendicular to the drill bit by using an engineer’s square set on the table and against a drill bit or true rod. This method of determining square may have enough undetectable imprecision to lead one to believe that a non-square hole problem is attributable to something other than alignment. Another method could be tried, which measures directly whether the table is perpendicular to the bit. The direct measurement method eliminates any undetected errors that may exist in the engineer’s square, steel rod, and any other things used to check for square.

This could be done with a thick block of wood (2-1/2” minimum), perhaps 12” long (the longer the better) that sets absolutely flat on the drill press table. Drill a hole deep with a ½” diameter bit into the block of wood at one end while keeping the wood firmly flat on the drill press table using a slow feed rate. Once the hole is drilled, turn off the drill press while the drill bit remains in the just drilled hole. When the bit has stopped spinning, raise the bit with block of wood still engaged on the bit just enough so the drill bit and block of wood can be rotated together on the bit by 180 degrees. In this position, lower the drill bit and the block of wood until the block of wood contacts the table. Any daylight under the block of wood, between the block of wood and the table reveals the table and bit are out of square. Then, spinning the bit and block of wood together 90 degrees checks the front to back alignment.

Jack Forsberg s method also looks like pretty good way to check for/confirm square. However the table must be flat and smooth, at least wherever the dial indicator measurements are taken.

- JBrow

One a DP you have to check for 90/square every 90 on the table. too many variables.

- conifur


-- Knowledge and experience equals Wisdom, Michael Frankowski

View Rick M's profile

Rick M

7909 posts in 1841 days


#7 posted 04-30-2016 04:36 AM

If you need it exact, like in machinist exact then the answer is don’t use a drill press, use a mill instead; or at least not an inexpensive DP designed for woodworking/hobbyist use.

-- http://thewoodknack.blogspot.com/

View TopamaxSurvivor's profile

TopamaxSurvivor

17654 posts in 3137 days


#8 posted 04-30-2016 04:37 AM

Drills and screws will wander in the grain ;-( A brad point is best. The smaller the drill bit the worse it gets.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View jim C's profile

jim C

1467 posts in 2559 days


#9 posted 04-30-2016 04:32 PM

Ken from Ontario has it right.
The only way to make sure the table is perpendicular to the quill is with an indicator “sweep” as shown in the youtube video.
Problem is woodworking drill presses are almost impossible to adjust the table. You can adjust from left to right (tweaking) but in most cases there is no front to back angle adjustment.
Rick M. was correct in utilizing a mill, as it has adjustments left to right, as well as front to back, and is much more robust.

-- When I was a boy, I was told "anyone can be President", now I'm beginning to believe it!

View lew's profile

lew

11335 posts in 3216 days


#10 posted 04-30-2016 06:30 PM

It might be that the quill race has some slop in it. Wiggle to chuck (side to side and forward to back) when the quill is fully retracted and again when the quill is lowered to almost its’ full range. If there is movement in to chuck, when lowered, that could be the reason the holes are not perpendicular.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View jim C's profile

jim C

1467 posts in 2559 days


#11 posted 04-30-2016 11:16 PM

Again, if you can get the table perfectly perpendicular to the spindle/quill, you will drill a straight hole. Period!

-- When I was a boy, I was told "anyone can be President", now I'm beginning to believe it!

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