???I set up the fence as per Paul Marcel mod. I squared the Guide Rail to the Fence by adjusting the Guide Rail Support/Pin. All was square and it all referenced perfectly off of the Qwas Dogs. Trouble is, when I make a test cut, it's out of square every time. So I adjust the guide Rail Support/Pin until I get a square cut and repeat it on different pieces. When I go back and check for 90* on fence to Guide Rail, it's out of 90*! Far as I can tell, nothing is moving when I make cuts. Anybody know what's going on? How can I be consistently be cutting square, when the fence is not square to the Guide Rail?
MFT Fence-Guide Rail Not Square,But Cuts Square???
- Thread starter darita
- Start date
Apparently the holes in the MFT/3 top are CNC'd so the holes should be square to each other, i.e. a "horizontal" row of holes (left to right) should be 90 degrees to a "vertical" column of holes (front to back). Therefore, when indexing off the qwas dogs, the horizontal dogs and vertical dogs should measures square.
However, the rail is set off the frame of the table, it is not attached to the perforated top. Therefore, if the perforated top was not exactly square in the CNC machine when made, or not attached exactly square to the frame of the MFT/3, the row of holes in the perforated top, although straight, would not be exactly parallel to the edge of the table. Mine is also off very slightly.
Therefore, when you set the fence alignment using the qwas dogs, and the rail alignment via the table frame, they are being indexed off two independent parts, thus are not automatically at 90 degrees to each other. You can certainly set the fence position using the qwas dogs for convenience as this alignment with the edge of the table will always be consistent even if not exactly parallel, but then align the rail position by using a square aligned to the actual fence rather than to a qwas dog on the top.
Obviously, if your top is in perfect alignment, you can just use the dogs. Just don't take it for granted, check first.
A second issue is slop between the rail and the positioner it is lowered into, but this slop (if it was occurring) would likely be fairly obvious. Solutions for the slop have been addressed elsewhere on FOG.
However, the rail is set off the frame of the table, it is not attached to the perforated top. Therefore, if the perforated top was not exactly square in the CNC machine when made, or not attached exactly square to the frame of the MFT/3, the row of holes in the perforated top, although straight, would not be exactly parallel to the edge of the table. Mine is also off very slightly.
Therefore, when you set the fence alignment using the qwas dogs, and the rail alignment via the table frame, they are being indexed off two independent parts, thus are not automatically at 90 degrees to each other. You can certainly set the fence position using the qwas dogs for convenience as this alignment with the edge of the table will always be consistent even if not exactly parallel, but then align the rail position by using a square aligned to the actual fence rather than to a qwas dog on the top.
Obviously, if your top is in perfect alignment, you can just use the dogs. Just don't take it for granted, check first.
A second issue is slop between the rail and the positioner it is lowered into, but this slop (if it was occurring) would likely be fairly obvious. Solutions for the slop have been addressed elsewhere on FOG.
Sparktrician
Member
Ironically I posted a video yesterday in response to a question from a member (not a member who has posted in this thread). There are lots of ways to calibrate. This is the way that I do it.
My way to set up a MFT/3 using Qwas Dogs
Peter
My way to set up a MFT/3 using Qwas Dogs
Peter
mastercabman
Member
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- Apr 15, 2007
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- 1,854
Peter
Nice video.But i have a question about the set up.
I understand how this work,if the fence is parallel with the holes and the guide rail is also parallel with the holes and the holes are in-line and squared then the two are also squared.
But you mention that you travel with your MFT, and I'm wondering how well those the table keeps everything squared? Or do you calibrate everytime you set it up?
I have the older version(1080)and really if you think about it,the MDF is really what keeps the whole thing secured.The problem with the 1080 is that the fence is attached to the MDF and the guide rail brackets on the side rails.So if the table top gets loose from the frame then it is most likely not square anymore.Does the MFT 3 really keeps it together well?
Nice video.But i have a question about the set up.
I understand how this work,if the fence is parallel with the holes and the guide rail is also parallel with the holes and the holes are in-line and squared then the two are also squared.
But you mention that you travel with your MFT, and I'm wondering how well those the table keeps everything squared? Or do you calibrate everytime you set it up?
I have the older version(1080)and really if you think about it,the MDF is really what keeps the whole thing secured.The problem with the 1080 is that the fence is attached to the MDF and the guide rail brackets on the side rails.So if the table top gets loose from the frame then it is most likely not square anymore.Does the MFT 3 really keeps it together well?
mastercabman said:
The MFT/3 fence / protractor head is a major improvement over the 1080 setup (my opinion after reading so many comments here.) I haven't had the MDF top shift in the frame. One of the major reasons I like setting mine up with this approach is that when you set the fence / protractor head on the table and lock it down you have a quick visual reference against the edge of the holes. If it is off by a tiny amount, you can use the outboard fence clamp thingy to correct, or you can pull out the Qwas dogs and make a 30 second adjustment.
In the video if you see saw kerfs running the long ways of the table you can see the parallel aspect. Those kerfs are from using Tom's technique for cutting / ripping cabinet parts.
Hope that this helps.
Peter
darita said:
Are you using the same square to check everything? If so, have you checked it for square? If you are sure it is accurate then you can forget the following.
It seems that you may begetting square cuts off the Quas settings but they may appear OOS with your measuring device. Then if you set the rail with your square you get cuts that match it, but if you square is not right you may be mislead. Try cutting a sample on all four sides in squence and see if it is square on the first to last corner. Your error will be multiplied. Use both techniques and see which one gives you the best equal length sides and equal length diagonals. That way you can eliminate your square as a gauge.
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