Saturday, December 11, 2010

Extending the Capacity of the MFK-700

The Festool MFK-700 has pretty amazing dust collection, but the horizontal bases (0º and 1.5º) require the use of pretty short bits.  If you use non-Festool bits, you're likely to run into this problem repeatedly.  I decided to fix that.

This entry is actually the first of three enhancements I'm making to the MFK-700 although arguably this is the most useful :)

Here is one of my favorite bits for flushing banding: a 1/4" spiral down-cut bit.  I have a bearing version I use in the OF-1400, but this bit is what I want to use in the MFK-700.  As you can see, there's an "issue".  This fix is essentially to remove that part of the base to make clearance for the bit or any number of other reasonably short bits.

Addendum: that 1/4" bit works for me, but some others who have done this modification find that they just can't get the base low enough to get the cut perfectly flush, so there's a variance (in one case, though, they did this to the 1.5 degree base).  Anyway, the best bit by far for this modification, and what I now use exclusively for flushing banding, is this 8mm down-spiral carbide bit (#1322) from Vortex Tools.  The larger diameter means you can definitely get it to flush with room to spare, full capacity of the modification, and a down-spiral so the flushing is the cleanest possible.

The portion you have to remove is done in two parts.  First part is marked here.  While this part gives clearance for the bit, it doesn't make the channel where the bit rides wider.  This will be clear in a photo later.

You'll want to "raise" the fence as much as possible to get the top (shown) far from the base (background).  This lets you use the fretsaw on an angle to make these cuts.

I'm using a fretsaw from Knew Concepts along with metal-cutting Pégas blades from Ben's Scrollsaw to cut away the bit clearance.  Yes, these were blatant plugs, but that saw and those blades make a fantastic combination.  Say goodbye to wandering blades ("goodbye!")

Okay, so anybody purchasing a Festool router base knows how difficult it would be to start cutting it up... but it cuts very cleanly with this blade.  You don't need the cut really clean; the second cut will clean it all up along with filing it.

Voilà!  Point of no return :)

For the second cut, we need to remove the bat ears I highlighted.  While they don't give more bit clearance, they make the channel for the stock narrow (the channel being the light portion of the base that is above the lower brown foot).  For this cut, I used a hacksaw to get the crosscut straight.

What's left now is to actually remove the bat ears so they are flush to the offset portion of the base.  Back to the fretsaw...

As you can see, there isn't much room for long passes with the fretsaw so it's slow-going, but you get there.  Cue up a long song.

Take a mill file to flatten the portion where the ears were and clean the edge made with the hacksaw crosscut.  I also used a half-round file to clean the round bit recess and soften some edges.

The final result with the bit having enough room.  Start to finish it might have taken a half hour.  This is a modification I'm certain to enjoy and take advantage of.


  • Peter Durand said...

    Could you let know where one can buy the 1/4" down spiral bit with bearings.

    BTW, I just discovered your site yesterday and have spent hours on it. And am now about $75 poorer after ordering the Kerfmaker :-)

    This is the best woodworking site I have come across. My hat off to you.



  • HalfInchShy said...

    Thanks for the great compliment, Peter! Sorry about the $75 :)

    For flushing with the MFK-700, an 8mm downspiral is the best as I've noticed a few variances when using the 1/4" bit. On mine, the 1/4" just makes it, but on at least one other person who contacted me, the 1/4" just misses leaving you with something to plane. The 8mm bit uses the 8mm collet you have with the MFK-700 and gets you a lot of adjustability for setting the bit flush.

    If you re-read the blog posting, there's a link to the page with carbide downspiral bits from Vortex. Very high quality bits for CNC and the price is on par with others. Anyway, the link in the article is for a whole page of bits on Vortex's site, but the bit's product number is in my article for you to find it on the site. Definitely get that one over the 1/4". You will have needed to make this modification to the 0º base for that bit to work for you.

  • Unknown said...

    I don't understand why the bat ears need to be removed. Could this work with only making the first cut? Seems so but maybe I'm missing something...

  • HalfInchShy said...

    Hi, Victor,

    Take a look at the channel extension first cut into the base. That's the first cut described. What that does is allow for a longer bit like I want to use for wider bandings, etc.

    With that cut out, look at the bat ears. Those are part of the base, the part that rides on the surface. Without removing the bat ears, you have part of the base that's in the way of proud stock getting to the extended portion of the bit. You need to lop them off so stock can flow into the cutters near the end of the bit.

    Hope that makes sense. If not, look at your base to see what I mean. You'll love the modification; to me it made the MFK-700 much more useful for what I do.

  • Unknown said...

    Hi Paul,

    So I've spent the last 54 weeks considering your response to my question about the bat ears. I now have began the layout with the piece of tape to make cut on the base for the modification. The Vortex bit seems to need to be set far enough in the collet that some of the flute is inside. Does that sound right?

    I'm wondering what is the depth of the cut you've made. I've marked it with the Vortex bit taken down to where the beginning of the flute is just touching the collet and I'm looking at a half inch deep cut. I'm not sure I can clear the upper rising portion of the base by angling the fretsaw.

    I did buy the Knew Concepts saw and the Pegas blades too by the way to make sure I was replicating the conditions.(I actually look for any minute excuse to insist on new tool purchases...)



  • Unknown said...


    I did the modification to the zero degree base and I'm very happy. I think I cut out a little more(~1/2") than your pictures show.

    Looks like it's gonna work out well.

    Did you do it to both the horizontal bases?

    Thanks again for guinea piggin' this awesome mod!!


  • HalfInchShy said...

    Sorry for not replying earlier, Victor... I saw the message on my phone, but replying from there is a chore! Plus I honestly needed to look at the base again!

    Glad you figured it out. Yes, that bit has just a little of the flute in the collet. Wish I could get a shortened version.

    I'm using it now with that modified 0º base to flush the drawer tiers for Angle Madness to the panels. Also used it to flush the pins and tails on the drawer boxes. Very nice.

  • Anonymous said...

    Paul awesome job showing this modification I bought the mft 700 just the other day to flush up the edges of the carcasses and face frames I built. I was super frusterated when I discovered I couldn't cut my 7/8 inch face frames edges. Long story short I was watching your review video when I was considering buying this little beast and remembered you saying you had to modify it to work on bigger stuff I found your blogspot post got the modification done in 1/2 hour and couldn't be happier just wanted to say thank you for sharing that info with the rest of us as much as I hate to modify a brand new zero clearance base, this change was well worth the risk thank you for sharing.

  • Gordon said...

    Paul what are the metal cutting blades you use from Pegas? Love the site. Been following you for a couple of years now.

  • HalfInchShy said...

    Hi Gordon,
    I use their #7 skip blades the most; seem to last long, don't break easily, clean cut. There are finer blades for sure, but really don't need that for what we do.