Ripping large panels accurately

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Old 12-05-03, 07:59 PM
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Ripping large panels accurately

I did a dry run (blade below table) of a 4x8' 3/4" plywood rip operation on my Jet Contractors saw with jury rigged outfeed table and I'm not totally convinced I can get an accurate cut.

For one, I could see the fence moving slightly. I know they have fences which secure on both ends but they cost more than my table saw. I suppose I could make a rough rip first with a circular saw but I still need confidence in making an accurate rip. This panel is only exterior ply but eventually I'd like to cut up some hardwood ply panels and mistakes could get quite costly.

Any tips on technique?

Thanks
 
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Old 12-06-03, 07:19 AM
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Alex,

Cutting a 4 x 8 3/4 inch anything is just about a two-man operation. And you need good out-table support for both sides of the cut.
But if your fence has moved during a trial run(blade down) you don't want to try a real cut just yet. If the fence moves even slightly during an actual cut, you're asking for a possibly serious kick-back situation. Your fence shouldn't move, Period!! Find out why it is giving. My Delta contractor's Unifence, after locked down, will not budge a bit.

Unless I need every inch of an uncut panel (rare) , I always make rough cuts anyway. Always use the factory cut against the fence.
It's considerably safer this way.
Others may have additional advice for you,

fred
 
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Old 12-06-03, 07:19 PM
CrackedDrumHead
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I have a table saw with a fence that moves a little also when cutting 4x8 sheets.

I had to rip a couple sheets one day, so I just laid and clamped my 8' level 1" away from my rip line, and cut the sheet with my circular saw alongside the 8' level. Of course how far you set the straight edge away from your rip line depends on your saw.

The cuts were damn straight. If you have a straight 2x4, you could use that too.
 
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Old 12-06-03, 09:41 PM
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Total surface to support the wood along with a stable fence are important in making straight cuts on large panels.

A contractor's saw has a smaller table than I would like to use. It may be that one of the guide edge rigs that clamp to the wood along the same line as clamping an 8 foot level as a guide to a circular saw may the best choice in your case.

A reliable straight edge is important. I have done some respectable panel ripping with a good straight edge and a circular saw. Good saw horses help. This may be a cheaper, more achievable, and reliable approach for you to consider.

Take a look at this:

http://www.signboards.com/howto/saw_guide/

Hope this helps.
 
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Old 12-07-03, 01:39 AM
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If you have the type of fence that doesnt wrap around the back side of the table saw, there will be adjustments to tighten your fence.

lift up your fence and look underneath below the handle. You will find two hex bolts. by turning them clockwise and counter-clockwise will not only tighten your fence, but it will align it properly too.

Move the screws so the bar its attached to moves outward, which will tighten the fence. slide your fence to the miter slot so it sits flush with it. next adjust the hex screws in and out until the fence is sitting completely flush with the miter slot at the beggining of the fence to the end of the fence. this will make your fence parallel to the blade.
 
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