Cutting Plywood/MDF for Router Table

C

Charles Wilson

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Mar 14, 2007
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145
Well, I am going to try and build Norm's Router table from NYW.  I am going to be cutting the plywood and the MDF to size.  Any hints/tips/clues as to how to get super accurate rips using the TS75?

Chuck

 
Not much to it.  Make two marks, being sure both measure the same distance from a reference edge.  Lay the guide rail right on the marks.  Cut.

One mistake I have made a few times is cutting on the wrong side of the marks.  Be sure you cut into the waste material, not the piece you want to save.  It seems to be a lot easier to make this mistake using a guided saw, since you can measure in either direction, and lay the rail down in either direction.

As with any circular saw, be sure you know where the cord and vac hose are before you start the cut.
 
Daviddubya said:
... Be sure you cut into the waste material, not the piece you want to save.  It seems to be a lot easier to make this mistake using a guided saw, since you can measure in either direction, and lay the rail down in either direction.
Click to expand...

At least with the Festool system the kerf is the only issue, since you're placing the guide edge on the intended cut. With the guides where you must run the saw base along the edge, you not only have the kerf to consider but also the blade placement in relation to the base. And since it's rarely centered, that measurement can vary greatly if you're not careful which direction you run the saw.

John
 
joraft said:
Daviddubya said:
... Be sure you cut into the waste material, not the piece you want to save.  It seems to be a lot easier to make this mistake using a guided saw, since you can measure in either direction, and lay the rail down in either direction.
Click to expand...

With the guides where you must run the saw base along the edge, you not only have the kerf to consider but also the blade placement in relation to the base. And since it's rarely centered, that measurement can vary greatly if you're not careful which direction you run the saw.

John
Click to expand...

Would you care to expand on this as I am not quite sure what you are trying to get at.

Chuck
 
I'm going to assume you will be cutting without the MFT table. To get nice and square sides, I like to use a framing square (already proven to be square) to assist in aligning the rail.

I like to use 3 measurement marks, use the framing square to keep the rail at that perfect 90 degrees from a precut side. If any measurements were off, it should stand out more with the 3 marks.
 
Chuck Wilson said:
joraft said:
Daviddubya said:
... Be sure you cut into the waste material, not the piece you want to save.  It seems to be a lot easier to make this mistake using a guided saw, since you can measure in either direction, and lay the rail down in either direction.
Click to expand...

With the guides where you must run the saw base along the edge, you not only have the kerf to consider but also the blade placement in relation to the base. And since it's rarely centered, that measurement can vary greatly if you're not careful which direction you run the saw.

John
Click to expand...

Would you care to expand on this as I am not quite sure what you are trying to get at.

Chuck
Click to expand...

Not sure which comment you are interested in clarifying, but I'll take a shot at it.

As John said, with the Festool method it is the saw blade kerf that is the issue.  As on all saws, cut so the kerf is on the waste side of the cut.

I think what John was emphasizing is that it is easier to get an accurate cut with the Festool saw and rail as compared to a conventional circular saw and guide.  The blade on a circular saw is almost never dead center in the base.  If you are cutting with the saw base edge against a guide, the possibility of a much bigger error looms if you cut in the wrong direction.
 
Daviddubya said:
As John said, with the Festool method it is the saw blade kerf that is the issue.  As on all saws, cut so the kerf is on the waste side of the cut.

I think what John was emphasizing is that it is easier to get an accurate cut with the Festool saw and rail as compared to a conventional circular saw and guide.  The blade on a circular saw is almost never dead center in the base.  If you are cutting with the saw base edge against a guide, the possibility of a much bigger error looms if you cut in the wrong direction.
Click to expand...

Exactly!

Thanks, David.

John
 
So, in cutting, how shall I accommodate the kerf of the blade?  From what people say, I am supposed to place the guide rail right on the mark.  If I do that, won't the cut be short?

Chuck
 
Chuck Wilson said:
So, in cutting, how shall I accommodate the kerf of the blade?  From what people say, I am supposed to place the guide rail right on the mark.  If I do that, won't the cut be short?

Chuck
Click to expand...

Chuck
  Place the guide rail so it is sitting on top of the good part, cutting edge toward the throw away part of the MDF.  That way your saw cuts on the side you're going to throw away, or in other words, cut the line so that the pencil marks stay on the edge you are keeping.
 
Maybe I've misunderstood what you're trying to do, but here's how I line up a cut with the guide rail:

1.  Assuming you've already used the saw and trimmed the black rubber friction strip, measure and mark (2 - 3 marks or a single line if you like) the cut line. 
2.  Position the guide rail with rubber tight (or practically on top of the mark) to the black rubber.  I'm right handed so I usually line up the rail to the left of the cut line whenever I can (I know this probably seems silly but the controls and handling of the saw just "fall" more naturally to hand when I cut this way).  The edge of the black rubber strip has been a very accurate indicator of where the cut will be (that is, the inside edge of the saw blade cuts right on the marked line if it's positioned directly on or tight to the line) for my purposes.
3.  Make sure you've got enough rail overhanging the start and finish of your cut.  If there's any chance the workpiece will move, clamp the rail to it.  I rarely use clamps when cutting 4x8 sheetgoods because I use the "sheet foam insulation on the floor/work table" method of cutting large sheets

I'm usually "spot on" the measured cut with this method.  When I'm cutting casework I make sure the workpiece is square.  It's hard making accurate cuts if your work isn't square in the first place.

My first saw was a TS55 (I now have the TS75).  Practice.  Before I cut my first workpieces with it I practiced making cuts against marked lines until I gained the confidence I needed to make accurate cuts.  What's great about the system is that there's not alot you can do to truly mess up a cut.  The more you use it, the more confident you become.

Hope this makes sense.
 
Chuck,

For multiple supper parrallel rips I like to make a pair of bench hooks with some scap. Length of bench hook = width of piece - guide rail width. Make sure to make them exactly the same length. clamp one hook to each end of the piece, place guide rail against the hooks and rip away. In cabinet making most gable widths are pretty constant so I have a pair of hooks for my often needed widths. It only takes a few minutes to make the hooks so if I have to make multiple pieces of the same width I always make them. It sure beats measuring and carefully aligning the rail for each rip and guarantees accurate rips.

I dont have the standard Festool MFT. I made my own and use an 18" precision triangle from woodpeck for my cross cuts.
I think for multiple crosscuts I would set up a fence at the front of the bench/mft and set stops that I could set the back of the guide rail against.

Hope that helps,

Eiji
 
Saw a handy tip on http://www.woodshopdemos.com - using two single edge razor blades, drive them into the wood slightly at your cut line.  When your cut needs to be dead-nuts accurate, this makes it easy to quickly and accurately set the guide to your marks without going back and forth fourteen times  ;D

Sometimes I'll use an adjustable square and work from what would normally be the off-cut side.  Allow for the kerf when setting the square, then use the blade to move the cutting edge of the guide rail into position.  This is effective for repeatable cuts, since there's no measuring involved after the initial setup.  If you make up a simple jig, you can make duplicate rips today, tomorrow, next year, and as long as your blade thickness doesn't change, they'll all be exactly the same.
 
As you can see, there are several good ways to go about this.  I usually use story sticks in a fashion similar to what Eiji has described with his bench hooks.  For my story sticks, I use two lengths of Incra's incremental jig track with stops.  The offset of the guide rail can be accounted for by adjusting the scales and tracks need only be calibrated once.  Just another way to do things.

Corwin
 
Hopefully this isn't asking too much, but pictures are great if you can post them as I am still quite the wood shop virgin.  ;D  At this point, a picture is worth a 1,000,000 words for me.

Thanks for the input and keep it coming.  :D

Chuck
 
I would like to resurrect this thread for an observation. I have been making carcasses for workshop cabinets using a TS75 that I borrowed and initially had a fair amount of trouble getting square cuts, I have used this saw quite a lot BTW. I am cutting across 600mm with a length of 900mm and over the 900mm was at least 2mm out of square and it drove me mad until I solved it. What I was doing was using a square parallel and up against the rail and the rail appeared to be spot on the measured lines. this method was just not accurate enough but I have found a way to do it very easily now. I have a T square which is 1000mm long and I get the rail as close as possible to right and lay the T square up against the rail raised section that the saw runs on and lay the blade down the length of the long edge, as accurate as I am it is always at least 1mm out over the length and needs a tiny bit of adjustment by moving the rail a minute amount. I can now cut dead square with no mucking around. Am I am missing something or do other people have trouble cutting dead square using the rubber strip for line up, I just find that for the purpose I am using it for more extreme measures need to be taken. Comments please.
 
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