MFT3

[jstockman]

Guys,

I am having trouble squaring panels for my in home cabinet job.  I have a question.

If I cut a piece of 4X8 sheet length wise marking from the long edge, can I use that new edge to cut cross cuts and if need be another paraelle cut.  And the finished panel be square on all four corners.  (this assumes the mft3 is set up correctly).

I have looked through the posts on mft3 but haven't put the posts together to come up with a definitive answer.

Thanking everyone in advance.

Jim

 

[harry_]

In short, yes. Again,this assumes the mft3 is set up correctly.

However for ease of handling, I generally do all my rips first.

 

[bonesbr549]

Guys,

I am having trouble squaring panels for my in home cabinet job.  I have a question.

If I cut a piece of 4X8 sheet length wise marking from the long edge, can I use that new edge to cut cross cuts and if need be another paraelle cut.  And the finished panel be square on all four corners.  (this assumes the mft3 is set up correctly).

I have looked through the posts on mft3 but haven't put the posts together to come up with a definitive answer.

Thanking everyone in advance.

Jim

Long edge short edge it's all about preference.    For me I get two sides parallel then cut one 90 to a prarallel side and flip the panel 180 and cut the final.    Just for giggles I have an engineers square and check the first 90 to see if its true.  If not adjust cut again.  Secondly I always cut them big and sneak up on the final just in case she's off a frog's hari.  Thats the way I do it, but then that and 50cents will get you a cup of coffee (not the good stuff)

 

[Neill]

I know that I am just a hobbyist, but it seems to me that the longer the cut, the greater the chance for error.  I would start out with my crosscuts and then my rips.  The only problem here is that you will waste some material if you do not need the whole width of the board.  It may be worthwhile though in terms of time, accuracy, and ease of material handling.

Of course, you will always want to check your your boards for squareness to be sure the factory edges are square.

Neill

 

[harry_]

I know that I am just a hobbyist, but it seems to me that the longer the cut, the greater the chance for error.  I would start out with my crosscuts and then my rips.  The only problem here is that you will waste some material if you do not need the whole width of the board.  It may be worthwhile though in terms of time, accuracy, and ease of material handling.

Of course, you will always want to check your your boards for squareness to be sure the factory edges are square.

Neill

Neill,

It is for the reason you stated that your long cut should be first.

 

[Corwin]

I know that I am just a hobbyist, but it seems to me that the longer the cut, the greater the chance for error.  I would start out with my crosscuts and then my rips.  The only problem here is that you will waste some material if you do not need the whole width of the board.  It may be worthwhile though in terms of time, accuracy, and ease of material handling.

Of course, you will always want to check your your boards for squareness to be sure the factory edges are square.

Neill

Neill,

It is for the reason you stated that your long cut should be first.

Yep, I have to agree.  Every so often here, someone talks about making their crosscuts first and then their rips.  I always view this as a mistake -- unless your initial crosscut is simply to break the material down to a more manageable size and NOT cut to a final dimension. 

 

[Brice Burrell]

Here's a quick rundown on the process that should help you get perfectly square piece.

First, make a cut along the factory edge. Cut off 1/16"-1/8" or so. This will give you're a straight, clean edge to work with.
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Next, measure from the freshly trimmed edge and make a couple of tick marks.  Measure carefully, these marks need to be precise.  
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Now, place your rail on the tick marks and make the cut. Be sure to have the rail on the piece you want. You'll end up with a piece that edges that are perfectly parallel. Note: since the ends haven't been touched yet we will assume that are not square to our parallel edges.
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Next, cut the first end perfect square to the edge (either edge since they are perfectly parallel). There is any number of ways to get make this cut perfectly square. My favorite is to use the MFT. Another way is to use a square to align the rail as you place it on the material.
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The final step is to measure and make your tick marks. Place the rail and make your final cut. If the rail was placed square to the edge you will have a perfectly square piece.
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Be sure to check you pieces to make sure they are all square (using a good square).
Good luck.

 

[Corwin]

Nicely illustrated, Brice!

I would note, however, that cuts are seldom made perfectly parallel or square.  They may be close enough, but perfection is often elusive.  So, I would make one adjustment to Brice's process;  when you make your last cut, reference off the same edge that you referenced off of for the first perpendicular cut.  This still offers no guarantees, but is good practice.

The wood shop at our local high school has a very large banner that hangs above the cabinets that reads, "Faces, Edges, Ends" -- as that is the order in which you should process your material.

 

[Brice Burrell]

.....So, I would make one adjustment to Brice's process;  when you make your last cut, reference off the same edge that you referenced off of for the first perpendicular cut.......

Yes, good point Corwin, I shouldn't have assumed that as a given.

 

[RONWEN]

.....So, I would make one adjustment to Brice's process;  when you make your last cut, reference off the same edge that you referenced off of for the first perpendicular cut.......

Yes, good point Corwin, I shouldn't have assumed that as a given.

To clear this up even more, both perpendicular end cuts should be referenced from the first clean up edge cut with either a good large square or the well aligned MFT (as opposed to making the second end cut by measuring parallel to the first end cut or any referencing from the second edge cut). -- this avoids compounding any error along the way.

 

[Corwin]

To clear this up even more, both perpendicular end cuts should be referenced from the first clean up edge cut with either a good large square or the well aligned MFT (as opposed to making the second end cut by measuring parallel to the first end cut or any referencing from the second edge cut). -- this avoids compounding any error along the way.

Yes, you don't want to make the last end cut parallel to the previous end cut.  Both ends should be cut perpendicular to one, and only one, of the long edges -- I don't see where it matters which of the two long edges you reference off, just as long as it is the same long edge.

This was the point that I tried to get Lloyd to understand with his MFT setup.  He was/is using his MFT setup to cut material to length -- material that he already had ripped to width on his table saw -- and making those end cuts parallel to each other.  I understand how someone might think that this would be a viable option, but I really think this to be a bad practice. 

 

[RONWEN]

To clear this up even more, both perpendicular end cuts should be referenced from the first clean up edge cut with either a good large square or the well aligned MFT (as opposed to making the second end cut by measuring parallel to the first end cut or any referencing from the second edge cut). -- this avoids compounding any error along the way.

Yes, you don't want to make the last end cut parallel to the previous end cut.  Both ends should be cut perpendicular to one, and only one, of the long edges -- I don't see where it matters which of the two long edges you reference off, just as long as it is the same long edge.

This was the point that I tried to get Lloyd to understand with his MFT setup.  He was/is using his MFT setup to cut material to length -- material that he already had ripped to width on his table saw -- and making those end cuts parallel to each other.  I understand how someone might think that this would be a viable option, but I really think this to be a bad practice. 

I agree though I have just gotten into the habit of marking that very first cut edge and referencing everything else that follows from it.  That way I don't get confused later (very easy for me to do  [smile]).

 

[fso]

I know that I am just a hobbyist, but it seems to me that the longer the cut, the greater the chance for error.  I would start out with my crosscuts and then my rips.  The only problem here is that you will waste some material if you do not need the whole width of the board.  It may be worthwhile though in terms of time, accuracy, and ease of material handling.

Of course, you will always want to check your your boards for squareness to be sure the factory edges are square.

Neill

Start with the longest cut first for the best accuracy. Say you need to cut 800x600 mm shelves from a 2450x1200 sheet. You would start ripping it to 600 wide and than cross cutting. After cutting a reference edge, you would measure the first parallel cut at 600 mm. In my case I may get accurate to about 1 mm. So my error would be 1 / 2450 = parallelism error of 0.023  degrees.

If I would have cross cut first to the 800 mm width, my error on the 600 mm would be 1 / 800 = error of 0.071 degrees.

My standard setup is to rip the sheet first, followed by cutting it to length on the MFT, squaring both ends at the same time.

 

[jstockman]

Thanks again all of you. 

Now I will get this head knowledge to my feet!

Regards,

Jim

 

[Wonderwino]

I use the parallel guides to get two new paralelllel edges.  Then I line up the back of a rail with one perfect edge, using my fingers to ensure it is lined up perfectly, butt another rail up to it and lay a framing square against the inside of the rails to enure a perfectly square, accurately registered cut.