Hey guys just started cutting last night, have the Dewalt 611 without spindle control. With the dail on the top what is a good speed for cutting mdf with a 1/4 inch bit?
Thanks again guys!
From what I have been reading on this forum, a speed of 1 or 2 is preferred for most cutting jobs.
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The dial speed will depend on a few things, including the size of bit and number of flutes. As a habit, I try to keep it down to 1 or 2 to help make the brushes last a lot longer.
Having said that, I would recommend trying to find the ideal feed/speed for each individual bit on each board, and keep a record of them. PreciseBits has a good procedure that you can modify at Calibrating Feeds and Speeds When Using Carbide Microtools. I’ve seen a couple versions of the 611 manual that have different RPM’s listed for each dial setting, so you will need to check your specific manual to determine the RPM on your device.
The way I do my feed/speed testing is to make a 4" line that’s .001" wide, and as deep as the max cut depth I want to do in a single pass. Then start with a feed 75% of what you calculated from the above website, and tweak it up or down as necessary to get a clean cut. You may have to reduce the cut depth in order to make that happen, I’ve noticed that my straight flute bits have to go shallow but fast while my upcut bits can go deep but have to go slow.
A basic thumbrule around here is to make the cut depth no more than half the diameter of the bit. I would recommend starting at about 3/8 of the bit diameter, and tweak it down once you’re comfortable with it.
Keep in mind that if your feedrate is too slow, you will start rubbing your bit and heat it up, causing it to dull quicker and possibly burn edges. If it’s too fast, you’ll get chattering and can break a bit. The correct answer for a problem may not always be to reduce your feedrate, it will depend on what’s happening with the cut.
Without being able to answer your question, I hope this helped you out at least a little bit. 
Speed 1, if i get any sort of chatter i bump it up until it clears up, never had to go past 2.5.
Speed 1 or 2 for 1/4" spiral upcut straight cutters.
Peter
I’ve been using speed 3.5 and a feedrate of at least 1000mm/min (40 ipm) and depth of cut of 2 - 3 mm. That’s worked well for me so far. When I back off the speed lower than that at that feedrate, the XC feels rough.
If you smell burning and your bit is hot, the speed is too high.