Dadoes

[loriny]

Does anyone know if the software allows for a cleanup pass on blind dadoes. I chose a .06" in settings for the cleanup pass but it doesn't do an extra pass. I think I get a bit of deflection and end up with tight dadoes as well as a slight ridge on the face of the panel where the tenon is.(approx 1/32) This results in cabinets about 1/16 oversize as well as a tiny gap at the front and back of the cabinet between the deck and the side.
Lorin

[Gary Campbell]

Lorin...
I believe you are confusing "clearance" for "cleanup".

When you set a side CLEARANCE for your dados, this is the extra amount that is taken out on the sides for material variation and glue.

The same is true of the depth clearance setting, it is an extra amount to allow for glue and/or variations beyond what the tenon is cut when using blind dados.

Adding clearance will not result in an extra "cleanup" pass similar to what is common with an area clear operation using a CadCAM vector based application.

For comparison, I use .010-.012 for a side clearance and .015 to .020 for a depth clearance. This has resulted in very nice joints. I would even be tempted to use these as a glue only joint should the need arise.

Can you explain better the location of the ridge you describe on the face of the panel? THere may be a cutting strategy to eliminate this.
Gary

[loriny]

Thank you
I meant .006 not .06. I see what you mean and I will increase these to get an easier assembly.
The ridge is from a slight bit of deflection of the cutter I think. The tenons are cut to depth in one pass while the cut out is done in 2. This results in the front and back of these panels with blind dado joinery being cut to exact size but the part above the tenon on the blind dado joint being slightll larger. A thought I had is to do these in 2 passes until I can justify a spindle and a drill. For now possibly my router and 5mm compression bit may have to much deflection.
Lorin

[loriny]

oops. I was right in original post. When in settings in shopbot link it was .06" set for cleanup pass in dadoes.
What settings do others use.(for all the settings in dado section)
thank you
Lorin

[loriny]

I am still having trouble with tight dadoes. I changed my side clearance to 1/80" (.0125). Still to tight. I wonder if anyone has ideas. My next thought was to set max depth on dadoes to .25 for my dadoes to force a second pass.
Also I found out I should use a collar value other than zero in my settings as the bit deflection on my climb passes affects cut quality on the part next to it and leaves it bevelled in in the middle. Oh well, live and learn.
Lorin

[thewoodcrafter]

I use .020 clearance sides and depth.
I also go .375 deep for all dados.

I also use .25 for collar.

[loriny]

Will try with these settings when I next need to cut.
Thank you
Lorin

[erik_f]

Make sure your bits measure out correctly. If your bits are .003" undersized, you are actually looking at a dado that will be .006" too small. Also try using conventional cutting with the same file...it will change things. Also if I am looking for more accuracy I reduce my depth of cut and speed. Do some searches...I know I have posted and asked a lot of questions on this sort of topic.

[loriny]

I had a close look at the dadoes and the ends are slightly wider than the rest. It must be bit deflection. I will try 2 passes and see how it goes.

[Gary Campbell]

Lorin...
What model/age is your machine? Spindle/Router/RPM? Bit size? Move Speed? These parameters may help solve or reduce your problem.
Gary

[loriny]

I have a prt 96. 2006 model., I have a 3.5 hp milwaukee router and set the rpm at around 12-14000 rpm. I am cutting with a 5mm compression fron centurion at 150 ipm.
Lorin

[Gary Campbell]

Lorin...
At those speeds, there is no reason to have anything but near perfect cuts. Check to see if you have any loose mechanical items, or if your pinions may be worn. I have just replaced the pionions on my 2007 PRSa, and even tho I couldnt see or measure any difference with a mic, there was a noticble increase in cut quality.

Another note, at speeds less than 5ips (300ipm) you will not get any noticable deflection from a 5mm bit. My guess is that you have something in the mechanical end that is causing the cut problems.
Gary

[loriny]

I am replacing my router as soon as the new one arrives. It has a bit of play in the z direction and possibly in the xy. It probably has 250-300 hours on it so I am trying a new one. It seems as if my whole z axis flexes slightly if I put pressure on it at the base of the router pushing in the x direction. I think this is normal though. I have just replaced my x and y pinions. For now I may just pocket hole my next job and then play around when I have time.
Thank you
Lorin

[Gary Campbell]

Lorin...
This is of course unscientific, but when I experienced similar problems, I used a dial indicator magneted down to a foot square steel plate on the table, set against a 1/2" drill rod in the collet, and using a fish scale pulled on the drill rod about 25 lbs in every direction. I then moved up and checked the Z extrusion, YZ car and finally the end plates of the gantry (PRS) to find where the loose parts were.

I would surprised to see how much dial indicator movement showed up on sections that "felt" tight. Most of my problems were in the Z roller wheels, some in the YZ car wheels, some in the YZ car pinions. When all was adjusted, there was a major decrease in what I thought was bit deflection. It turned out to be a maintenence issue.

Like I said above, it is highly unlikey that you are experiencing deflection at those speeds, it is more likely that something is out of adjustment. This, of course, could mean your router bearings is one of the culprits.
Gary