MFT square problem

[Hurricane Whisperer]

I am making a sheet good cutting table and it is made with lots of dowel joints.  Sort of like a torsion box but without the offsets between stringers and no tops.  The squareness and lengths of all the stringers and longitudinals is critical.

I got this idea on how to square the MFT guide rail to the hole grid.  I already have a Tool Improvements Slop Stop which is an excellent idea and excellent value. 

The OF 1400 guide rail attachments can be adjusted to near zero slop and I was able to clamp a dial test indicator to it.  I put some precision dogs in two holes and a 24" square blade against them.  I ran the dial test indicator against the blade until I was able to get within 2 or 3 thousands over the entire length.

I made a cut and the part was perfectly square.  A squareness with no light, no hollidays, and a squareness you can actually hear when you set the square against the piece.

So now I can't stop checking the squareness.

I checked every part.  And I smiled every time. God help me.  The perfection so satisfying it made me a little crazy.

 

[Sparktrician]

I am making a sheet good cutting table and it is made with lots of dowel joints.  Sort of like a torsion box but without the offsets between stringers and no tops.  The squareness and lengths of all the stringers and longitudinals is critical.

I got this idea on how to square the MFT guide rail to the hole grid.  I already have a Tool Improvements Slop Stop which is an excellent idea and excellent value. 

The OF 1400 guide rail attachments can be adjusted to near zero slop and I was able to clamp a dial test indicator to it.  I put some precision dogs in two holes and a 24" square blade against them.  I ran the dial test indicator against the blade until I was able to get within 2 or 3 thousands over the entire length.

I made a cut and the part was perfectly square.  A squareness with no light, no hollidays, and a squareness you can actually hear when you set the square against the piece.

So now I can't stop checking the squareness.

I checked every part.  And I smiled every time. God help me.  The perfection so satisfying it made me a little crazy.

"A little..."? 

[poke]

 

[tdwilli1]

I am making a sheet good cutting table and it is made with lots of dowel joints.  Sort of like a torsion box but without the offsets between stringers and no tops.  The squareness and lengths of all the stringers and longitudinals is critical.

I got this idea on how to square the MFT guide rail to the hole grid.  I already have a Tool Improvements Slop Stop which is an excellent idea and excellent value. 

The OF 1400 guide rail attachments can be adjusted to near zero slop and I was able to clamp a dial test indicator to it.  I put some precision dogs in two holes and a 24" square blade against them.  I ran the dial test indicator against the blade until I was able to get within 2 or 3 thousands over the entire length.

I made a cut and the part was perfectly square.  A squareness with no light, no hollidays, and a squareness you can actually hear when you set the square against the piece.

So now I can't stop checking the squareness.

I checked every part.  And I smiled every time. God help me.  The perfection so satisfying it made me a little crazy.

I was just thinking about using this process. How did you clamp the dial indicator to the rail?

 

[Hurricane Whisperer]

I was just thinking about using this process. How did you clamp the dial indicator to the rail?

I have an OF 1400 router.  It has a pair of attachments to connect it to the guide rail through the use of two rods.  The attachments have screws to adjust the slop where the guide rail attachments interface with the guide rail.

Festool calls these attachments the Guide stop 492601.  One of the attachments has a micrometer adjuster on it.  You can separate the two halves and tighten the micrometer adjustment so that it doesn't move.  My dial test indicator included a clamp that allowed me to clamp to the end of the micrometer adjustment.  I could slide the guide stop with indicator up and down the rail and the indicator indicated off of a square blade that was located on the back side of the rail and was against two dogs.  The distance was shorter off the back edge of the guide rail which allows you to reduce error due to having the indicator at the end of a rod.

The indicator allowed me to quickly adjust the rail as I could see how much it was out and adjust to cut the indicated amount in half then retest.  The Slop Stop reduces slop to near zero which is also important to have.

Alternatively, you may be able to attach to something on a track saw or a router or even the rods that stick through the guide stops to guide the router.

The way I did it resulted in very little slop movement so I could get a good read on the indicator.  The indicator I used part of somewhat odd starret 196 kit that comes with clamp and a ID attachment that works like a see saw.  Those two parts let me put the follower of the see saw against the blade while be able to read the indicator.

Having a test indicator would probably be easier and having a thicker straight edge would also be easier. 

 

[fshanno]

Sounds like an interesting cutting table. 

I take a more holistic approach to the squareness of parts I cut from sheet goods, namely, they ain't gonna be.  With that as a baseline I work forward toward a finished product that is pleasing nonetheless. 

At this point I don't think I could work with reliably square and accurate components.  Such as those produced by CNC and so on.  They are incompatible with my joinery, assemble and installation methods. 

 

[grbmds]

Accuracy is important. Squareness is important. Festool excels at accuracy. Be careful, though, that you don't get too caught up in the whole squareness thing so much it becomes an obsession. I have found that I can cut more accurately than I ever have with my MFT, TS55 and, for routing, the OF1400. However, are my cuts perfectly square? Probably not. However, they are very close; close enough that I really couldn't do any better with any other tool or really can't tell they aren't perfect when the finished product is done. So, I have started to take a different view of accuracy. My eyes and hands contribute to the inaccuracies and I can only adjust tools and my other measuring devices to a certain point before I can't do any better.