Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
After I cut, I checked the diagonals. NOT even.
I checked the blade to the miter slot - dead on.
I checked the blade square to the table - dead on.
I checked the fence to the miter slot - dead on.
Fence was locked down tight.
Each of the measurements were done using a
dial gauge or a Wixey angle measurement.
The only think I can think of is that the fence
is flexing. It's a Jet contractor saw with
the original (not an Xacta) fence. Aluminum box
type frame to the fence.
Any thoughts? I cut some spare 1/2 plywood and
came out dead on to the diagonal.
I am thinking of just re-cutting from a fresh sheet
and see what happens.
MJ
On Sep 30, 9:59=A0pm, "[email protected]" <[email protected]>
wrote:
> > How much off?
>
> 1/8 of inch. Building a box that needs to be
> square.
>
> MJ
When you make your cut, does your kerf stay the same width or does it
either widen or narrow?
I have run into MDF that had some 'reaction' problems with internal
stresses. Hasn't happened often, but I have had kerfs close up and
widen.
Uneven absorption of humidity will do that as will temperature either
in your shop or on the factory floor.
<[email protected]> wrote:
> Cutting some MDF panels. They are
> 18x16.5, 3/4 MDF.
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? I cut some spare 1/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
-------------------------------
Check your technique.
Are you keeping your eye on the fence/material joint or the blade?
If blade, you'll have problems.
BTDT
Lew
<[email protected]> wrote in message
news:3598b7ec-717a-4120-84ce-0a5c44f84319@e34g2000prn.googlegroups.com...
> Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
>
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? I cut some spare 1/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
>
My suggestions;
1) Make sure that the saw blade is equal to the task. Is it sharp. Is it
straight, etc?
2) Make sure that the area is clean. That there is nothing between the stock
and fence.
3) If the fence is flexing, clamp something behind it to make sure it does
not move. I had a cheap contractors saw that I had to do this with.
Something small and thin, no problem. Anything 3/4" or more, I had to clamp
the fence so it would not flex.
4) Make sure you have a straight edge to begin with. Then make all cuts
using the straight edges as a reference.
5) Check for square after the first cut. Don't cut everything, then check. I
learned that one early. You will save money on materials.
6) How secure is the stock when you are cutting? Any slippage or??? One
problem with cutting panels on a table saw is that by being safe, sometimes
you do not get the stock up against the fence all the way through. That is
where some good rubber based grippers can come in handy.
7) And last, but not least, you can break down and make up a sled or two.
Good luck. Let us know what you figure out and your solution.
On Oct 1, 7:26=A0am, "dadiOH" <[email protected]> wrote:
> [email protected] wrote:
> >> How much off?
>
> > 1/8 of inch. Building a box that needs to be
> > square.
>
> > MJ
>
> Are the two edges *parallel*? =A0If so, your sheet wadn't square to begin=
with
> and you have no cutting problem.
>
> --
>
> dadiOH
> ____________________________
>
> dadiOH's dandies v3.06...
> ...a help file of info about MP3s, recording from
> LP/cassette and tips & tricks on this and that.
> Get it athttp://mysite.verizon.net/xico
A perfectly set up fence will cut perfect parallelograms all day, all
you really need is one perfect 90=B0 corner.
<[email protected]> wrote in message
news:3598b7ec-717a-4120-84ce-0a5c44f84319@e34g2000prn.googlegroups.com...
> Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
>
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? I cut some spare 1/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
>
> MJ
The things you checked will ensure parallel, not square. What are you doing
to square the board? Did you measure the width of the board? Is it
consistent? Explaining your procedure step by step will make it a lot easier
to give advice.
On 9/30/2010 7:08 PM, [email protected] wrote:
> Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
>
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? I cut some spare 1/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
Remember, your fence only insures a cut parallel to the edge against it.
If the perpendicular edge to that cut is not 90 degrees, your diagonal
will be exactly as you describe.
Try a fresh sheet that you've checked for square on at least one corner
before making your first cut, the use only those two edges for your cuts.
--
www.e-woodshop.net
Last update: 4/15/2010
KarlC@ (the obvious)
In article <[email protected]>, [email protected]
says...
>
> [email protected] wrote:
> >> How much off?
> >
> > 1/8 of inch. Building a box that needs to be
> > square.
> >
> > MJ
>
> Are the two edges *parallel*? If so, your sheet wadn't square to begin with
> and you have no cutting problem.
If you need it square, you really need to make up a sled big enough to
hold the size sheet that you're working with, or at least the part. Or
make up a panel saw and make sure that _it_ is square.
<[email protected]> wrote in message
news:3598b7ec-717a-4120-84ce-0a5c44f84319@e34g2000prn.googlegroups.com...
> Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
>
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? I cut some spare 1/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
>
> MJ
If you are assuming that a previous 90 degree corner was square, it probably
wasn't.
On Sep 30, 8:08=A0pm, "[email protected]" <[email protected]>
wrote:
> Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
>
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? =A0I cut some spare =A01/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
>
> MJ
How much off?
<[email protected]> wrote in message
news:3598b7ec-717a-4120-84ce-0a5c44f84319@e34g2000prn.googlegroups.com...
> Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
>
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? I cut some spare 1/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
>
> MJ
Sawdust or other debris between the board and the fence or miter?
Art
There's a good chance that the sheet was out of square before you started.
I would rip 1st (1/2" oversize, 1st cut, then trim to size) and use a sled
for crosscutting.
--Woodson
<[email protected]> wrote in message
news:3598b7ec-717a-4120-84ce-0a5c44f84319@e34g2000prn.googlegroups.com...
> Cutting some MDF panels. They are 18x16.5, 3/4 MDF.
>
> After I cut, I checked the diagonals. NOT even.
>
> I checked the blade to the miter slot - dead on.
> I checked the blade square to the table - dead on.
> I checked the fence to the miter slot - dead on.
> Fence was locked down tight.
>
> Each of the measurements were done using a
> dial gauge or a Wixey angle measurement.
>
> The only think I can think of is that the fence
> is flexing. It's a Jet contractor saw with
> the original (not an Xacta) fence. Aluminum box
> type frame to the fence.
>
> Any thoughts? I cut some spare 1/2 plywood and
> came out dead on to the diagonal.
>
> I am thinking of just re-cutting from a fresh sheet
> and see what happens.
>
> MJ
>
[email protected] wrote:
>> How much off?
>
> 1/8 of inch. Building a box that needs to be
> square.
>
> MJ
Are the two edges *parallel*? If so, your sheet wadn't square to begin with
and you have no cutting problem.
--
dadiOH
____________________________
dadiOH's dandies v3.06...
...a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico