MFT holes; any size you like…




…except the one you need.


This is something I’ve been meaning to either write about or make a video around for a while, and I had a great question from Patreon supporter James Landis about the topic recently, and this post expands on my reply to James. James also made what looked like a great response to me - I received the notification, but being Patreon I’m unfortunately unable to find it! 🤷‍♂️

Anyway, James questioned my recent idea about making an MFT jig and getting a snug fit with a straight plunge from a router, not unreasonably raising questions about the precision required…


So, back when Festool started this whole MFT ‘thing’ it was designed as a mobile bench for clamping and cutting - very much a proprietary solution, and the machines that made the tops were expensive industrial items, definitely out of reach of the typical home user, even the deep-pocketed ‘retired doctor and dentist’ enthusiasts that Festool manage to market themselves to, so sucesfully.


Festool didn’t make - and to this day have never made - a benchdog. To them it’s a mobile table for clamping and cutting, and for whatever reason, they chose 96mm as the grid layout and 20.2mm as the size of the holes. More or less, anyway. Wether this is down to Festools’ proprietary nature, or just ‘one of those things’ (less likely IMHO) we’ll never know, but if you by an original Festool OEM MFT top as a spare part - I have one I bought to use as a template for a DIY top many years ago - it’ll have holes in it that are ~20.2mm in diameter.


So we had the Festool MFT - it’s just a table with holes in it, right? - and the first time I came across it was way back on The Festool Owners Group (FOG) forum, (back when it when it was just a fan forum run by Matthew Schenker and long before Festool USA became involved) when a few folks voted it as their most used Festool. I took a look, laughed (then cried) at the asking price, and thought ‘one day…’ And eventually, that day came around and I picked up a well-used MFT 1080 for a handful of cash. OK, maybe two handfuls.


In the meantime, the rest of the world figured out aluminium benchdogs, arguably starting with the QwasDog - again a FOG premiere - but many more followed thereafter. Combine this with the desire for cheaper MFT tops, and the accessibility of (relatively) affordable non-industrial CNC machines and by some kind of mutual but unspoken international agreement, everyone settled on 20mm as the definitive size.


This was not the Festool ‘standard’ but the world collectively shrugged, and got on with the benchdog business based around this new 20mm standard, which made the business of making a top with a grid of holes in it much easier.


I believe that Benchdogs UK usually work to a 19.98mm standard, and that’s a snug fit in a 20mm hole. Other benchdog makers - yes, I’m looking at you, UJK - have tied a bit of proprietary-ness of their own making some of their dogs a slightly off-size - and then flogging a ‘reamer’ tool to make regular tops work with them.


Standards, as the old joke goes, are fantastic, because there are so many to choose from…


And so to router bits for boring MFT holes - the ‘which bit’ question is one of the most asked, and it’s a topic I’ll be addressing in a forthcoming member video, but suffice to say that the “20mm” router bit that Festool sells specifically for making MFT holes… actually produces a hole between 20.16 and 20.2mm across. I know this because I bought one, couldn’t believe how loose the holes were, and had my precision engineer pal check it over in his very precise engineering drill press and comparing them to what I was getting off my router.


And then he ground it down for me to make a perfect fit with my standard Benchdogs UK and it’s that bit I use when making my tops  using my LR32 method.


As I say, there’s more to come on this in a member video in the next couple of weeks so I won’t give the game away now,  but it’s all tied in to the 10MW MFT/Plus jig, and the idea is to make a close fit with regular benchdogs using standard and slightly customised components. 👍


Cheers for now, Peter

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