I just found out that the drill press table I made last week to include
a vac channel for sanding is almost useless.

Last weekend while making the table I routed a 1/4 recess for hardboard
inserts... I thought I made a mistake when the hardboard sank lower than
the top...I didn't understand how that happened. But I figured I had a
brain fart. I went and bought a new board of hardboard 2 days ago and
today I find out not all hardboard is 1/4". Of three different samples
only 1 is actually 1/4"
The measurements a
.196 = 5mm
..225
..250
So even though they are all marked 1/4 they aren't. So to fix my sunken
plate I glued formica inserts into the routed channel to raise it. Now I
cut a true .225 plate and it is too high... Wish I known b4 I fixed a
problem that wasn't really broken in the first place. Now I have to
re-route the formica out.

In many products, a nominal thickness is used. The actual product varies in
thickness plus or minus an allowable amount. One that comes to mind is metal
sheeting. The ranges for 29 gauge and 26 gauge overlap by a small margin on
some of the charts I have seen.

I have made the same mistake as you. How many times can a person measure
twice, cut once and still be wrong...... I am still finding out.

Jon

"tiredofspam" nospam.nospam.com wrote in message
...
I just found out that the drill press table I made last week to include a
vac channel for sanding is almost useless.

Last weekend while making the table I routed a 1/4 recess for hardboard
inserts... I thought I made a mistake when the hardboard sank lower than
the top...I didn't understand how that happened. But I figured I had a
brain fart. I went and bought a new board of hardboard 2 days ago and
today I find out not all hardboard is 1/4". Of three different samples
only 1 is actually 1/4"
The measurements a
.196 = 5mm
.225
.250
So even though they are all marked 1/4 they aren't. So to fix my sunken
plate I glued formica inserts into the routed channel to raise it. Now I
cut a true .225 plate and it is too high... Wish I known b4 I fixed a
problem that wasn't really broken in the first place. Now I have to
re-route the formica out.

I'm so glad I ordered a dial caliper from Harbor Freight. With it, I've
found that most of the stock I use varies from nominal
dimensions...sometimes by a considerable margin. Now I make my cuts to fit
the materials instead of relying on the stated size. For twenty bucks, it's
a tool I highly recommend.

To combine this with another current thread...using the dial caliper, I was
able to make a VERY accurate box joint jig on the second try (and tuned it
for perfect usability on the third).

"tiredofspam" nospam.nospam.com wrote in message
...
I just found out that the drill press table I made last week to include
a vac channel for sanding is almost useless.

Last weekend while making the table I routed a 1/4 recess for hardboard
inserts... I thought I made a mistake when the hardboard sank lower than
the top...I didn't understand how that happened. But I figured I had a
brain fart. I went and bought a new board of hardboard 2 days ago and
today I find out not all hardboard is 1/4". Of three different samples
only 1 is actually 1/4"
The measurements a
.196 = 5mm
.225
.250
So even though they are all marked 1/4 they aren't. So to fix my sunken
plate I glued formica inserts into the routed channel to raise it. Now I
cut a true .225 plate and it is too high... Wish I known b4 I fixed a
problem that wasn't really broken in the first place. Now I have to
re-route the formica out.

In article vvDId.138108$KO5.54269@clgrps13, "Jon"
wrote:

In many products, a nominal thickness is used. The actual product varies in
thickness plus or minus an allowable amount.

In wood products, especially sheet wood products, there's no chance of
it being plus anything, and also none that will remotely approach the
nominal thickness. 7/16" "half inch" plywood is with us until they
decide that we are dumb enough to buy 3/8" "half inch" plywood. (at
which point the 7/16" will be labeled as "three quarters of an inch")

It's not like the government is going to force them to advertise the
truth, or sell true dimensions. You'll notice that the class action suit
regarding lies about the horsepower of air compressors has had no effect
whatever on the lies about the horsepower of vacuum cleaners, tablesaws,
circular saws, etc...

--
Cats, Coffee, Chocolate...vices to live by

In wood products, especially sheet wood products, there's no chance of
it being plus anything, and also none that will remotely approach the
nominal thickness. 7/16" "half inch" plywood is with us until they
decide that we are dumb enough to buy 3/8" "half inch" plywood. (at
which point the 7/16" will be labeled as "three quarters of an inch")

It's not like the government is going to force them to advertise the
truth, or sell true dimensions.

In Canada, poly vapour barriers used to be labelled as 2, 4, & 6mil. The
thickness of each size hadn't been anywhere near the 2, 4, or 6 thousandths
of an inch in 20 years. The government forced manufacturers to use the
descriptions: Light, Medium, Heavy, and 6mil (which actually has to be 6
thou. and is required in residential construction and has a manufacturer's
number printed on the poly along with the code approval numbers. As a side
note, I had a building inspector reject some poly because it had what he
thought was the wrong number on it. This was the manufacturer's number not
the code approval number. I had to fax him the list of all manufacturer's
numbers before he would allow it to be used. Seems like there should be an
inspector for inspectors). Anyway, in anything lighter than 6mil, the
manufacturers now make an even thinner product than they did before.

Jon

"Jon" wrote in message
news:INEId.138253$KO5.92071@clgrps13...


In Canada, poly vapour barriers used to be labelled as 2, 4, & 6mil. The
thickness of each size hadn't been anywhere near the 2, 4, or 6
thousandths of an inch in 20 years.


Everything has a tolerance for manufacturing. Years ago, it was difficult
to stay very close to the stated size. The poly extruders have gotten so
refined that they can now hit it extremely accurate and now they stay on the
minus side as the norm. Technology improved but the stated tolerances
remain.

Once you get that fixed, simply drill and counter sink a small hole in each
corner of the routed out area, countersink far enough for the screw to sit
flush. Then when you get hardboard on the thin side, adjust the screws up
to level the insert. The Rockler router table I have uses the same idea for
inserts of various thicknesses.

John Cunningham

"tiredofspam" nospam.nospam.com wrote in message
...
I just found out that the drill press table I made last week to include a
vac channel for sanding is almost useless.

Last weekend while making the table I routed a 1/4 recess for hardboard
inserts... I thought I made a mistake when the hardboard sank lower than
the top...I didn't understand how that happened. But I figured I had a
brain fart. I went and bought a new board of hardboard 2 days ago and
today I find out not all hardboard is 1/4". Of three different samples
only 1 is actually 1/4"
The measurements a
.196 = 5mm
.225
.250
So even though they are all marked 1/4 they aren't. So to fix my sunken
plate I glued formica inserts into the routed channel to raise it. Now I
cut a true .225 plate and it is too high... Wish I known b4 I fixed a
problem that wasn't really broken in the first place. Now I have to
re-route the formica out.

Ecnerwal wrote:
In article vvDId.138108$KO5.54269@clgrps13, "Jon"
wrote:


In many products, a nominal thickness is used. The actual product varies in
thickness plus or minus an allowable amount.


In wood products, especially sheet wood products, there's no chance of
it being plus anything, and also none that will remotely approach the
nominal thickness. 7/16" "half inch" plywood is with us until they
decide that we are dumb enough to buy 3/8" "half inch" plywood. (at
which point the 7/16" will be labeled as "three quarters of an inch")

It's not like the government is going to force them to advertise the
truth, or sell true dimensions. You'll notice that the class action suit
regarding lies about the horsepower of air compressors has had no effect
whatever on the lies about the horsepower of vacuum cleaners, tablesaws,
circular saws, etc...

I am aware of plywoods 1/64 given back to the lumber producers ... I
also knew that hardboard wouldn't be exactly 1/4 but the .196 isn't in
the ball park, and .250 being that much over was surprising. ... anyway
I figured I could make replaceable inserts anytime but was wrong. I will
make blanks when I fix my problem and be more careful next time.

Isn't measure once cut twice...three times... 8)

Thanks, I did that too my router table too. I think I will just use
masking tape build up on the blanks if they differ. A little easier than
trying to level the screws each time I replace a blank. Since the
drums will have different size blanks it is a big deal. The drilling
blanks I will go thru fast... I have holed the drilling blanks to suck
up the shavings... works nice.

snowdog wrote:

Once you get that fixed, simply drill and counter sink a small hole in each
corner of the routed out area, countersink far enough for the screw to sit
flush. Then when you get hardboard on the thin side, adjust the screws up
to level the insert. The Rockler router table I have uses the same idea for
inserts of various thicknesses.

John Cunningham

"tiredofspam" nospam.nospam.com wrote in message
...

I just found out that the drill press table I made last week to include a
vac channel for sanding is almost useless.

Last weekend while making the table I routed a 1/4 recess for hardboard
inserts... I thought I made a mistake when the hardboard sank lower than
the top...I didn't understand how that happened. But I figured I had a
brain fart. I went and bought a new board of hardboard 2 days ago and
today I find out not all hardboard is 1/4". Of three different samples
only 1 is actually 1/4"
The measurements a
.196 = 5mm
.225
.250
So even though they are all marked 1/4 they aren't. So to fix my sunken
plate I glued formica inserts into the routed channel to raise it. Now I
cut a true .225 plate and it is too high... Wish I known b4 I fixed a
problem that wasn't really broken in the first place. Now I have to
re-route the formica out.

"tiredofspam" nospam.nospam.com wrote in message
I also knew that hardboard wouldn't be exactly 1/4 but the .196 isn't in
the ball park, and .250 being that much over was surprising. ... anyway

..196 seems to be well under, but .250 is not over anything if the spec is
1/4"

"Jon" wrote in message
news:vvDId.138108$KO5.54269@clgrps13...
In many products, a nominal thickness is used. The actual product varies
in thickness plus or minus an allowable amount. One that comes to mind is
metal sheeting. The ranges for 29 gauge and 26 gauge overlap by a small
margin on some of the charts I have seen.

I have made the same mistake as you. How many times can a person measure
twice, cut once and still be wrong...... I am still finding out.

An unknown previous owner of my house made some washable filters for
the furnace using galvanized sheet metal, plastic screening and some sort of
filter medium. He made them exactly 20" X 20" and 10" X10" which is what
is printed on the disposable filters. They aint as labeled, they're about
1/4"
scant so these really well made filters sat up on top of the frame and let
all sorts of dust through.
Brian, in Cedar

Edwin Pawlowski wrote:

"tiredofspam" nospam.nospam.com wrote in message

I also knew that hardboard wouldn't be exactly 1/4 but the .196 isn't in
the ball park, and .250 being that much over was surprising. ... anyway


.196 seems to be well under, but .250 is not over anything if the spec is
1/4"



Doh....
Thanks for keeping me straight.