# Can't get a straight edge..AHH



## flamingoezz (Oct 13, 2015)

I'm a woodworker from a former life -- haven't really done any fine woodworking since high school but picked up a table saw and want to start doing it as a hobby.

I don't have a jointer and have seen videos where people use a jig to get a straight edge on a board. I tried building a similar jig but am having some trouble.

after i run it through the saw, i put a level to it. the back half of the board is straight as can be, but about half way down you can start seeing some light under the level. by the end theres a little more light -- we're talking maybe 1/32". I've run several boards with the same result.

I'm keeping my jig against the fence as far as I can tell. Is there something I can look for in my saw setup or technique in running long boards (56") that might cause the front of my board to be a little shallow?

I assume 1/32" will give me some issue in edge glue up -- if that is the case, and im unable to get the table to make a straight enough cut, do you think a small hand plane will work to get it close enough for gluing? I don't have a larger #7 or 8 plane and haven't really picked up a plane in decades. Could use some ideas or advice from some people with experience.


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## Steve Neul (Sep 2, 2011)

Perhaps there is something wrong with the saw but more than likely the blade is too dull for that kind of work. A blade that is a little dull can bend while making the cut.


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## bigshake (Aug 5, 2015)

I'm very new to woodworking and tackled some large red oak countertops recently. I used the same method to get the edges prepped for glue up and had some areas that weren't 100% tight. To my eye they appeared to be about 1/32 as we'll. 

I talked it over with my dad(long time hobby woodworker) and he assured me the gaps would not be a problem. So far so good with the tops and they have been in place for ~6 months.

May not be the 100% correct answer but it worked ok for me.


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## hwebb99 (Nov 27, 2012)

I would check the alignment of the saw first. .005 misalignment of the fence was giving me trouble on my saw. If that doesn't fix it try adding a feather board. If that doesn't fix it I would buy a good quality blade.


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## epicfail48 (Mar 27, 2014)

Is the level straight? If youre using a non-straight reference edge, well, yeah, your cut wont be straight. Try cutting 2 boards using your jig, then butt the cuts against each other. Check for gap that way, just to rule out the level being the problem


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## GeorgeC (Jul 30, 2008)

hwebb99 said:


> I would check the alignment of the saw first. .005 misalignment of the fence was giving me trouble on my saw. If that doesn't fix it try adding a feather board. If that doesn't fix it I would buy a good quality blade.


99 44/100 per cent of wood workers could not measure 00.005. And that small of an error would not matter in woodworking even if they could measure it.

How can you use a feather board on that type of jig?

George


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## was2ndlast (Apr 11, 2014)

epicfail48 said:


> Is the level straight? If youre using a non-straight reference edge, well, yeah, your cut wont be straight. Try cutting 2 boards using your jig, then butt the cuts against each other. Check for gap that way, just to rule out the level being the problem


Yeah, levels are not the best indicator of a straight edge. Flip it around when measuring to rule it out.

Also I can't see how a table saw can cut a straight edge for half a cut and not on the second half...unless the blade starts to wobble or something. The cut would be off by a certain amount in a linear fashion along the length of the cut. E.g. every inch you would be off by say 5 thou...


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## woodnthings (Jan 24, 2009)

*an 48" aluminum level is a good test*

That's what I use for a straight edge when setting up my jointers. It's about the most precision tool you can buy for a modest amount, around $30.00 or so AND you will use it for other tasks.

You did not say how long your pieces are OR how long your level is, OR what it's made from... wood or metal?
You fence should look like this with a 1/16" to 1/8" offset behind the blade from a scrap of Formica or other thin material:









You do need a very sharp blade for this and you must feed slowly to avoid bending the blade. A full kerf blade is the best for this operation and it need not be a full 10" diameter. A stiff blade like from a dado set will work.


As to technique, when ever you joint a board, you must sight down it before jointing. If it has a concave curve, you should "joint/plane" in from both ends to reduce the curve as much as possible, just like you would do if you were planing by hand. This is important and few instruction manuals mention it. After there is very little curve left, run it through your setup and check it with a straight edge or aluminum level. Do the same with the next board and then match them together to check for gaps/daylight between them.

If all the above are taken into account, you should have as good a mating surface as possible.... :yes:


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## hwebb99 (Nov 27, 2012)

GeorgeC said:


> 99 44/100 per cent of wood workers could not measure 00.005. And that small of an error would not matter in woodworking even if they could measure it. How can you use a feather board on that type of jig? George


 It does make a difference. Set your fence .005 tighter at the back then the front and see how that works out for you. I adjusted it where the front of the blade is .002 closer to the fence then the back with much better results.


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## FrankC (Aug 24, 2012)

hwebb99 said:


> It does make a difference. Set your fence .005 tighter at the back then the front and see how that works out for you. I adjusted it where the front of the blade is .002 closer to the fence then the back with much better results.


5 thousands of an inch is the thickness of a sheet of writing paper, on most saws once the fence is moved it will not likely even remain at that same tolerance, any improvement using a dial gauge to set up a saw is purely physiological.


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## woodnthings (Jan 24, 2009)

My pencil lines are wider than .005 " :blink:


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## flamingoezz (Oct 13, 2015)

I checked out my saw this AM and found that the fence is not running parallel to my blade. Hoping this may be causing the issue.

Could it also be that I'm using boards that are slightly bowed? The jig definitely holds the bow down pretty well while cutting, but I'm trying to figure anything else that could attribute to the issue. I need to get these ready for glue in the next 48 hours.

If I'm unable to get them straight enough with my saw, I'm gonna have to look at other options. I've got a small rusty old hand-me-down hand plane -- will that get the job done or do i need a #7 or #8 plane to really get it straight? any other ideas that won't cost much?


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## flamingoezz (Oct 13, 2015)

matt, im curious if the clamps closed up your gaps or if you mean there are small gaps but the glue holds ok.



mattshake9451 said:


> I'm very new to woodworking and tackled some large red oak countertops recently. I used the same method to get the edges prepped for glue up and had some areas that weren't 100% tight. To my eye they appeared to be about 1/32 as we'll.
> 
> I talked it over with my dad(long time hobby woodworker) and he assured me the gaps would not be a problem. So far so good with the tops and they have been in place for ~6 months.
> 
> May not be the 100% correct answer but it worked ok for me.


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## bigshake (Aug 5, 2015)

Yeah the gaps closed up with moderate clamp pressure. I used tightbond 2 for the glue up and all seems well for now. In the 3 separate top pieces I was good for 1 gap per glue up. It seemed to me that the gaps happened within a few inches of the end of the board. I believe it happened at the start of the cut not the end. Possibly being at a very small angle to the fence when starting out. The shortest pieces were about 5 foot long and the longest pieces about 8, so control was difficult at the start. 2 inch thick oak is heavy.


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## woodnthings (Jan 24, 2009)

*did you read post no. 8?*



flamingoezz said:


> . I need to get these ready for glue in the next 48 hours.
> 
> If I'm unable to get them straight enough with my saw, I'm gonna have to look at other options. I've got a small rusty old hand-me-down hand plane -- will that get the job done or do i need a #7 or #8 plane to really get it straight? *any other ideas that won't cost much?*


Just get your setup and technique down correctly.


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## GeorgeC (Jul 30, 2008)

flamingoezz said:


> I checked out my saw this AM and found that the fence is not running parallel to my blade. Hoping this may be causing the issue.
> 
> Could it also be that I'm using boards that are slightly bowed? The jig definitely holds the bow down pretty well while cutting, but I'm trying to figure anything else that could attribute to the issue. I need to get these ready for glue in the next 48 hours.
> 
> If I'm unable to get them straight enough with my saw, I'm gonna have to look at other options. I've got a small rusty old hand-me-down hand plane -- will that get the job done or do i need a #7 or #8 plane to really get it straight? any other ideas that won't cost much?


"I checked out my saw this AM and found that the fence is not running parallel to my blade. Hoping this may be causing the issue."

Will not cause this issue but causes other problems.

I think you stated your real problem in a later post when you said you may not have the material solid against the fence at the start.

George


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## FrankC (Aug 24, 2012)

mattshake9451 said:


> Yeah the gaps closed up with moderate clamp pressure. I used tightbond 2 for the glue up and all seems well for now. In the 3 separate top pieces I was good for 1 gap per glue up. It seemed to me that the gaps happened within a few inches of the end of the board. I believe it happened at the start of the cut not the end. Possibly being at a very small angle to the fence when starting out. The shortest pieces were about 5 foot long and the longest pieces about 8, so control was difficult at the start. 2 inch thick oak is heavy.


You should have tool stands at both ends of your saw if the material is to heavy to manage properly. You can buy them, or build something yourself to do the job, lots of ideas out there.

Clamps are meant to hold two fitted boards together until the glue dries, forcing gaps closed usually results in other problems.


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## woodnthings (Jan 24, 2009)

*there is an exception ....*



FrankC said:


> Clamps are meant to hold *two fitted *boards together until the glue dries, *forcing gaps closed *usually results in other problems.


There is a technique that relies on a gap between the boards. It's called a "spring joint" and is used when edge joining boards. I've never used it, but it requires lowering the outfeed table on the jointer to create a slight concavity on the edge. This article explains it:
http://www.finewoodworking.com/item/26796/spring-joints-an-edge-glue-ups-best-friend


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## FrankC (Aug 24, 2012)

:laughingoing it intentionally is an entirely different situation, and the gap is not at the ends. Sometimes a little knowledge is a dangerous thing.


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## Big Mike 69 (Oct 20, 2015)

If I remember you said that this gap was consistent. If these boards are being glued as you cut one lay it down, cut the next and flip end to end so the grain pattern reverses on the ends which should be done to keep the finished board from warping any way. So if the gap was consistent this flipping should remove that gap. Lots of good advice. This type of problem is best solved on location as you are the only one seeing the solution possibilities.


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## woodnthings (Jan 24, 2009)

*rereading the first post .....*



flamingoezz said:


> I
> 
> *I'm keeping my jig against the fence as far as I can tell. *Is there something I can look for in my saw setup or technique in running long boards (56") that might cause the front of my board to be a little shallow?
> 
> .


I want to see this jig. Is it a straight line rip jig where the work is clamped down and the right edge of the jig is registered along the fence OR is it a type of jointing method using the table saw as I posted above?
Which?

jointing method using a table saw:









Straight line rip jig:


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## Chaos1 (Feb 24, 2013)

I have a lot of success using a router as a jointer. When set up right you can get an edge that will stand up to any other method.


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## hwebb99 (Nov 27, 2012)

Chaos1 said:


> I have a lot of success using a router as a jointer. When set up right you can get an edge that will stand up to any other method.


 True, but setting it up is a trial and error process and slow to get right. Although it does work it is no substitute for a real jointer. I would rather use the straight line rip jig then the router.


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## FrankC (Aug 24, 2012)

It is a matter of whatever works for you, and how much money you want to spend.

Some systems seem more natural than others to use, some could use any accurate system and get perfect results, others it would not matter how accurate or how expensive if they don't have the feel for the job.

There is no magic bullet unfortunately.


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## woodnthings (Jan 24, 2009)

*I like the straight line jig I built*










I built 2 lengths, one around 5 ft the other at 8 ft. I can get a straight edge far faster with the jig on an 8 ft piece than I could using a jointer and support tables. Given the choice, I'll use my jigs every time.


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## FrankC (Aug 24, 2012)

woodnthings said:


> I built 2 lengths, one around 5 ft the other at 8 ft. I can get a straight edge far faster with the jig on an 8 ft piece than I could using a jointer and support tables. Given the choice, I'll use my jigs every time.


That would be my first choice as well, have never had a problem with one.


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## hwebb99 (Nov 27, 2012)

The table saw jig still can't replace a jointer because the jointer is needed to get a flat face on the board. A big enough jointer doesn't need support tables. To be fair you build an out feed table for the table saw. The same can be done for the jointer.


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## woodnthings (Jan 24, 2009)

*the thread's title says "straight edge" ....*



hwebb99 said:


> The table saw jig still can't replace a jointer because the jointer is needed to get a flat face on the board. A big enough jointer doesn't need support tables. To be fair you build an out feed table for the table saw. The same can be done for the jointer.














So yes, you can't get a flat "face" using a table saw, but that wasn't the issue here. I've seen extension tables that attach to the jointer's tables made from wood and metal to eliminate the need for floor supports. I hate roller floor supports as they always are at the wrong height and fall over when you bump them. A heavier base would help prevent that and one of my large roller supports .... shop made/welded will not tip over. 










However, for a fast edge joint I break out the shop built straight line jig and ... I'm done in a heartbeat.
And for a whole stack of boards ....


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## hwebb99 (Nov 27, 2012)

What method of router jointing do you use? I can think of at least 2 ways to do it.
Method 1 use another straight edge and flush trim bit. 



















Method 2. Use a fancy router table with a off setting fence. This method really isn't very good because it has a shorter "table" then pretty much any jointer. 









One big plus to the table saw jig would be lumber that wasn't originally squared on the sawmill and needs a large amount of material removed to make it flat. 

I can imagine not having a good jointer. I use it nearly every time I am in the shop.


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## Wendel17 (Apr 20, 2009)

I use a shop made offset fence. Add a layer of laminate (formica, wilsonart...) to the outfeed side, and you'll take off the thickness if the laminate. Post-form will be around 1/32". 

I just rough cut on the table saw first, then clean up the edges on the router.


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