Perfect Cross-Cuts?

[Dansmith]

Thanks for all the responses. I have been away from home, and have not had the opportunity to use a computer.

As an aside, I went to my first Woodcraft store in Boise, Idaho. Wow, that place was impressive. Bought a few goodies and browsed the store on 2 separate occassions (had to go back for more browsing ). I certainly wish I had one of those stores in my small city.

I hope to get back to resolving the squareness issue today.

[Dansmith]

I don't normally measure to see how far things like that are off but I do use a square and if I can see light I fix it. I went to the trouble of find a piece of wood that is close to 4" wide, actually 3-15/16 and with an error of .008" via a feeler gauge this is what you see:

IMG_3860sc.jpg

I don't know at what point you can't see light anymore but it is a lot less then this.

Ed

Thanks for going through the trouble, Ed. Much appreciated.

[Dansmith]

I cant tell for sure,,,,, the picture looks like the cut starts out {{{{{ends up, depending on the direction you are feeding the stock,,,}} it's pretty straight for a little bit ?

Do you use the hold down on the miter gage ,I wouldn't think the table would move using the miter gage ?

.008 is like 8 100ths of 1 1000th

Cut is pretty straight for a little bit. I imagine that if I were using a 12" square on a 12" board, the amount would be greater than about .008". I do use the hold down with no significant difference from when I don't use it, if I recall correctly.

[Dansmith]

using a sharp knife blade,,,, and you square ,or even 2 different squares , score a line as close to the cut as possible and see if the cut is straight ?

If not it could be drift when you are feeding the stock through the blade.


To me the cut looks high in the center.

I will try that. Thanks.

[JPG]

I don't normally measure to see how far things like that are off but I do use a square and if I can see light I fix it. I went to the trouble of find a piece of wood that is close to 4" wide, actually 3-15/16 and with an error of .008" via a feeler gauge this is what you see:

IMG_3860sc.jpg

I don't know at what point you can't see light anymore but it is a lot less then this.

Ed

If this works AIUI the image does not propagate within a quote.


i.e. One does not need to 'remove' it.



I have come up with a possible???? explanation if the 'light' is on the leading edge of the cut.


Blade wobble! That wobble flattens out after the blade is a ways into the kerf and the cut is then 'perfect'.

[Dansmith]

Thanks Paul and Hobbyman2. I will keep trying, and I also suspect it is "creep" caused by my technique. I will not give up. I am intent on making the "perfect" cross-cut.

It is good that you are not going to quit trying but you do not need feeler gauges to check wood working.

Setup your machines using normal techniques and whatever pass fail criteria you want (I use .005") and go make saw dust.

Keep in mind that you can be no more accurate than your tools. How square (and how repeatable) is your combination square?

Reible posted a picture (this thread) showing a light reveal between the work piece and the square. Use this between to quick check your cross cuts and you will be building some fine pieces. Especially if you get to the point of "No light". This is going to be somewhere between 1/64" (.015625" ) and 1/128" (.0078125").

Thanks, Dusty. I wouldn't generally use a feeler guage' but, I am doing everything I can think of to figure this out. I am going for the no light status. I will get there

[Dansmith]

I don't normally measure to see how far things like that are off but I do use a square and if I can see light I fix it. I went to the trouble of find a piece of wood that is close to 4" wide, actually 3-15/16 and with an error of .008" via a feeler gauge this is what you see:

IMG_3860sc.jpg

I don't know at what point you can't see light anymore but it is a lot less then this.

Ed

If this works AIUI the image does not propagate within a quote.


i.e. One does not need to 'remove' it.



I have come up with a possible???? explanation if the 'light' is on the leading edge of the cut.


Blade wobble! That wobble flattens out after the blade is a ways into the kerf and the cut is then 'perfect'.

Thanks. I did get a new blade that has a 5/8" arbor. I may try that today. By the way, thanks for the tip on the image. I will go back and edit.

[Sazerac81]

Hey Dan,

I don't necessarily think you should shoot for the "no light" status because you may never be happy.

Here are a few examples:

First round of pictures is with a piece of pine 2x4 jointed on one edge and then straight cut on a single bearing quill mark V with the incra v 120 miter guage. I do have a double bearing quill Mark V as well, but since the saw was on the single bearing quill setup for testing purposes, I just ran it on there.

The 'feeler guage' is a 0.001" shim. I had to somewhat gently force it a little bit underneath the edge of the board to show you what it would like with a powerful LED light behind it.





Without a shim and no strong backlight:



Wider piece of white oak using same technique without shim and with shim:

Without shim:





With shim:





No shim and No back light:



So, even with just a 0.001" shim wedged underneath the square, you get a little bit of light bleed through.

Last pic showing my two most used squares. I started with the empire square, but was never fully confident it was 'square' and purchased the woodpecked square. At almost 6 times the price, it better be square (I hope).



Now, I am pretty happy with my empire square since it is quite square at this point as referenced off of the woodpecker square. It loses a bit of squareness as you extend the length of the square.

Ultimately, I think feeler guages will give you an acceptable reference vs. aiming for virtually 'No light'. As demonstrated, even a 0.001" shim can show light bleed through. I suppose it all depends on what is acceptable to use for whatever your purposes. A 0.005" difference on a 12" crosscut is perfectly acceptable in most case scenarios.

Cheers,
John

[Dansmith]

Hey Dan,

I don't necessarily think you should shoot for the "no light" status because you may never be happy.

Here are a few examples:

First round of pictures is with a piece of pine 2x4 jointed on one edge and then straight cut on a single bearing quill mark V with the incra v 120 miter guage. I do have a double bearing quill Mark V as well, but since the saw was on the single bearing quill setup for testing purposes, I just ran it on there.

The 'feeler guage' is a 0.001" shim. I had to somewhat gently force it a little bit underneath the edge of the board to show you what it would like with a powerful LED light behind it.

...

So, even with just a 0.001" shim wedged underneath the square, you get a little bit of light bleed through.

Last pic showing my two most used squares. I started with the empire square, but was never fully confident it was 'square' and purchased the woodpecked square. At almost 6 times the price, it better be square (I hope).

[img]...[/img]

Now, I am pretty happy with my empire square since it is quite square at this point as referenced off of the woodpecker square. It loses a bit of squareness as you extend the length of the square.

Ultimately, I think feeler guages will give you an acceptable reference vs. aiming for virtually 'No light'. As demonstrated, even a 0.001" shim can show light bleed through. I suppose it all depends on what is acceptable to use for whatever your purposes. A 0.005" difference on a 12" crosscut is perfectly acceptable in most case scenarios.

Cheers,
John

Thanks, John. Lots of nice pictures. In any event, I agree that .001 would be absolutely acceptable. I'll report my latest in the next post.

[Dansmith]

I did it. I now have what I call satisfactory "perfection".

First off, this is a great forum with so many of you so willing to help out and going to great effort to do so. Thank you again.

I am now getting square cuts that I am willing to call "perfect". One thing I found, after purchasing a larger square (easier to tell with larger square) is that my miter gauge was off, and not at 90 degrees. The old eyes are not as good as they used to be either. Also, I think I am getting better technique in preventing slippage of the workpiece.

I am a very pleased. Thanks, again.