table saw technique help

[vavet]

I need some help figuring out how to set up my table saw to make a cut.
The workpiece is a 28 x 72 x 3/4 piece of melamine. One of the 72" edges is a factory edge - reasonably straight. I need a 45 degree bevel on one of the 72" edges. My table saw has an expandable table, but it only goes out to 24" so I can't use the TS fence.
I have the table saw mounted to a 6 foot long worktable. I was thinking I would just clamp a supplementary fence to the worktable where I needed it, but I think I need to know where the extended centerline of the blade is before I can do that to make sure the supplementary fence is parallel to the blade. I tried using an aluminum straightedge to mark the extended centerline, but when I tried to repeat my marks, I was off, so I'm not sure which one is right. It's hard to align an 8" section of straightedge to the blade to such a high degree of accuracy that any error is imperceptible when magnified out over 5 feet. The last picture I attached shows all the different pencil marks I made at the far edge of the worktable trying to find the centerline.


I've thought about trying to set up a string on a stand so that I could move the stand over a little at a time until I had good alignment with the blade. I haven't tried it yet. I figured I'd query the GJ braintrust for ideas.

 

[The Cobbler]

how about locking the saw fence at a given measurement from the blade. use your straight edge along that to reference ?
then make a trial cut on scrap to be sure you have it right

 

[McFarmer]

Skill saw mounted on a good sled, clamped down. Work from the bottom.

Sorry, all I got.

 

[greg13]

How about a router with a 45* bit?

 

[PelicanPines]

How about a router with a 45* bit?

I do this stuff all the time.... I would do what Greg says.

 

[turbowoodworker]

Yep, router.

 

[Bogie1632]

+2 for a circular saw. Simple, straight forward. Just clamp a straight edge down and use a good blade. IMHO, 3/4 being cut at a 45 degree is a good bit of wood that should be done in multiple passes to get a clean finish cut. If the edge doesn't leave enough for bit's bearing (if equipped) then you'd need a straight edge anyway. Why not 1 pass with a circular saw? YMMV.

Good luck.

V/R
Bogie

 

[fourbyford]

If all you're looking for is parallelism, measure from your miter slot. The slots are SUPPOSED TO BE parallel to the blade. This can easily be verified if you have a dial indicator... failing that, use your miter gage and some sort of a wood strip for reference. Raise your blade to full height (saw unplugged). With the wood strip set against the miter gage, push it (the wood strip) into contact with the infeed side of the blade... securely clamp it to the miter gage. Push the assembly forward and check the outfeed side of the blade. Measure the gap (if any) with a feeler gage. Correct any error. Now, you can measure for fence parallelism from your miter slot.

HTH

...D

 

[joe49]

+1 for a straight edge and Skillsaw.

 

[rlitman]

If all you're looking for is parallelism, measure from your miter slot...

Forget that idea. This is NOT somewhere where tape measure accuracy can be trusted (even if you have the lay-flat fixed-hook Fastcap tape). And forget the supplementary fence idea. It's not going to stay parallel against the forces of that slab, no matter how perfectly you set it up. In fact, forget the whole tablesaw idea.

I break down sheet goods like this with my circular saw, and I own a cabinet saw with a 60" fence! Get a good straightedge and go to town.

As for the 45 degree cut. Well, that changes things. I'm guessing you want this cut to line up a miter. Circular saws (and table saws) CAN do bevel cuts, but getting them to make a perfect 45 is challenging at best. If you need a stain grade perfectly meeting miter, do a rough cut 1/8" wide on the circ saw, and finish with a router.

edit:
One thing I'm noticing now. You have a two-piece aluminum straightedge. That might be fine for the circular saw, but I've had those go wishy-washy on me, leaving a not so straight cut. Either get yourself something stiffer, or clamp a board behind it before trying the router, or else you may end up with a concave edge. There can be a lot more side force involved when routing than when sawing.

 

[turbowoodworker]

Rlitmans has the correct technique.

 

[topcok88]

Sounds like a great excuse to buy a new tool - time to buy a track saw.


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[rlitman]

Sounds like a great excuse to buy a new tool - time to buy a track saw.

Every time I break down a sheet, I think about this. And then I remind myself that it might be years before I need to do that again, and I promptly drop the subject in my internal monologue.

So, to be fair, I have no experience with one, but at first glance, it seems like a good idea. However, a little googling tells me that bevel cuts on track saws still ****. Apparently the overhanging saw weight wants to lift the track, even on a Makita which has a unique anti-tip feature. tanstaafl

 

[TLCObsession]

However, a little googling tells me that bevel cuts on track saws still ****. Apparently the overhanging saw weight wants to lift the track, even on a Makita which has a unique anti-tip feature. tanstaafl

Nope - If you use tracksaw clamps there are no issues. I could make a perfect 45 in the case you are trying. Without my tracksaw, I would use a straightedge and a circular saw and cut it within 1/8" (tighter if I though I could hold it) and the hit it with the router using an edge guide.

 

[rlitman]

Nope - If you use tracksaw clamps there are no issues. I could make a perfect 45 in the case you are trying. Without my tracksaw, I would use a straightedge and a circular saw and cut it within 1/8" (tighter if I though I could hold it) and the hit it with the router using an edge guide.

I understand that you can clamp down the track at the ends. But what keeps it from lifting in the middle? (aside from just holding it down by hand)

 

[topcok88]

I am unsure what you mean by “tipping” I have never had my TS55 tip while doing a cut and using quick-clamps on the track ensures it doesn’t move. Using a router on the edge like that will have a greater tendency to tip than a track saw.


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[topcok88]

I understand that you can clamp down the track at the ends. But what keeps it from lifting in the middle? (aside from just holding it down by hand)

Watch a YouTube video of the Festool TS55 and look at were the weight of the machine is in relation to the pivot point of the saw. It doesn’t tip, move or act any different than a standard cut. The tracks don’t lift and the only variance will be if the material isn’t supported appropriately - that’s why a lot of us cut with a 4x8 sheet of foam under the sheet good.


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[joyridin]

Even a Festool Track saw is prone to 'tipping' when cutting at 45 degrees. There are some work arounds - see the attached youtube video. But if absolute accuracy is a must, I think rough cutting fairly close with a track saw to remove the bulk of the material and then a final cut with a router would do the trick

 

[rlitman]

I am unsure what you mean by “tipping” I have never had my TS55 tip while doing a cut and using quick-clamps on the track ensures it doesn’t move. Using a router on the edge like that will have a greater tendency to tip than a track saw.

We're talking about a BEVEL cut here.

Here's a video of your Festool TS55 explaining the issue I'm asking about.

edit:

Even a Festool Track saw is prone to 'tipping' when cutting at 45 degrees. There are some work arounds - see the attached youtube video. But if absolute accuracy is a must, I think rough cutting fairly close with a track saw to remove the bulk of the material and then a final cut with a router would do the trick

Exactly. You beat me to the post button.

 

[joyridin]

Watch a YouTube video of the Festool TS55 and look at were the weight of the machine is in relation to the pivot point of the saw. It doesn’t tip, move or act any different than a standard cut. The tracks don’t lift and the only variance will be if the material isn’t supported appropriately - that’s why a lot of us cut with a 4x8 sheet of foam under the sheet good.

Most track saws, including the Festool are designed so that the pivot point doesn't actually effect where the blade is going to cut, it has nothing to do with the weight of the saw. (you line up the edge of your track on the marks where you want to cut, and the blade will make the same cut either at 90 or 45). You can't design it both ways

 

[topcok88]

Most track saws, including the Festool are designed so that the pivot point doesn't actually effect where the blade is going to cut, it has nothing to do with the weight of the saw. (you line up the edge of your track on the marks where you want to cut, and the blade will make the same cut either at 90 or 45). You can't design it both ways

Yes, the pivot point keeps the blade flush with the track. The weight bias of the saw has the majority of the weighty components above the track on the track side of the saw. That’s why you can plunge cut so close to obstacles. My limited experience with my TS55 and tracks is that it doesn’t tip over. Maybe others have different experience or maybe the cordless saws have a different balance.



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[joyridin]

Yes, the pivot point keeps the blade flush with the track. The weight bias of the saw has the majority of the weighty components above the track on the track side of the saw. That’s why you can plunge cut so close to obstacles. My limited experience with my TS55 and tracks is that it doesn’t tip over. Maybe others have different experience or maybe the cordless saws have a different balance.

Now do it with the vacuum hose attached and hanging down to the floor along with the power cord. (did you get a chance to watch that youtube video I posted?)

 

[topcok88]

Now do it with the vacuum hose attached and hanging down to the floor along with the power cord. (did you get a chance to watch that youtube video I posted?)

CT MIDI I, 27mm vac hose attached, the power cable attached and TS55 at 45 degrees.




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[joyridin]

LOL - good one. Personally, I wouldn't trust an expensive saw to sit there on the edge of the table like that while you took the pic, because knowing my luck, it would fall off on to the concrete floor and break something

You have to admit though in that pic, it sure looks like it is pretty unbalanced

 

[topcok88]

LOL - good one. Personally, I wouldn't trust an expensive saw to sit there on the edge of the table like that while you took the pic, because knowing my luck, it would fall off on to the concrete floor and break something

You have to admit though in that pic, it sure looks like it is pretty unbalanced

It was so unbalanced it stayed there until this morning. And when I picked it up and set it on the top of the bench (not on the aluminum guide rail) it still stayed up in its own. My TS55 must be defective and I should probably return it for the fainting goat model.


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[vavet]

Thank you to everyone who contributed. The track saws are interesting. I ended up using the suggestion to measure off the fence to find the extended center line of the blade. It was long enough that I was able to be consistent enough to feel comfortable making that cut. I set up my aluminium straightedge (I used my 4-foot level across the joint between the two pieces to make sure it was straight) and ran the melamine panels across the table saw and outfeed table. I used a roller stand for the infeed. Overall it went well.

 

[joyridin]

It was so unbalanced it stayed there until this morning. And when I picked it up and set it on the top of the bench (not on the aluminum guide rail) it still stayed up in its own. My TS55 must be defective and I should probably return it for the fainting goat model.

Sorry, just saw this post today - I was using my tracksaw and it made me think of it

So here is what my tracksaw does when set to a 45 degree angle and is set down on a flat surface. Yes, it flops right over and doesn't even have the hose or cord attached. You can clearly see it is set to a 45 degree cut

So my saw does it, people have made youtube videos about the problem but your saw doesn't apparently seem to have this problem

example:
Is it just me or was the bevel cut feature of the track saw under thought? When you tilt the saw to 45* it wants to wall over so right off the bat the balance is off and required one hand holding down on the saw guide