Festool 20 mm hinge location router bit

[John Stevens]

I don't have the measuring tools to calibrate a 1/4 of a mm.  In my rough and tumble world of trim carpentry, wood moves at least  that much from morning to night.  Open a window, need a new measurement...  

Hi, Dan.  I use my MFT with the saw and router to make modern-style furniture that doesn't use mouldings to hide the places where one part mates with another.  Errors of a fraction of a millimeter will quickly multiply out to several millimeters when setting up the MFT fence to a 90 degree angle for cutting or routing.  I find that fixing or otherwise accommodating errors of that size always requires a lot more time of sanding or planing than preventing them from happening in the first place through careful setup.

That said, I think trim/finish carpenters and joiners perform magic.  The way you guys can install clear-finish hardwood crown moulding in a plastered room and not need any filler in the joints is beyond me, and always will be.  I'll be using plenty of caulk and paint this weekend when I finally get around to installing crown and picture moulding in two of our bedrooms.

Regards,

John

 

[Corwin]

Michael / All,

Please understand that I'm not trying to be a jerk here.  Really trying to understand the problem. 

If I read the posts correctly, we're talking about 2/10 or 2.5/10ths of a milimeter.  Are the bench dogs really not working?  They don't fit?  They are so loose that it's not possible to create fine woodworking with them?

I don't have the measuring tools to calibrate a 1/4 of a mm.  In my rough and tumble world of trim carpentry, wood moves at least  that much from morning to night.  Open a window, need a new measurement...   

What's up?      Dan

My experience has been that my MFT tops have, and do swell somewhat.  This has caused the tops to sag, which is a little bit of a problem.  The size of the holes may have changed some, but nothing anywhere near 0.010" -- rather, they have never changed more than a thou or two.  And, my shop is within walking distance of the sound (a large body of water).  The dogs I made for my tables a couple of years ago fit today just as they did a couple of years ago.  With these close tolerance dogs it is very obvious when there is any change between the size of the dog and the hole it is fitting into.  The variation from hole to hole within a table does not vary much more than a thou or two at most and you can easily distinguish the difference between these variations as you insert a dog into the hole.  So, that fact that wood moves has not had much effect on the size of the holes in my tables.

I would assume that many spend the time to accurately setup their miter saws and table saws.  And many use quality squares and other devices to do so.  These dogs are used to establish a relationship between your guide rail and either your fence or your material.  Shouldn't you do this as accurately as you would on any other tool?  If your initial setup is off by some 0.010", that may seem insignificant, but what about the other things that might add to that amount of error.  Your resulting work may end up further off than you want even if you aren't looking for that close a tolerance.  My point is that all these small factors can add up, and if you want decent results, you should start with a decent setup.  So, a dog that fits into a hole that is 0.010" too large is not the best start. 

I don't mean to be a jerk either by my reply.  I understand that each person has their own idea of what is good enough.  While typing this reply, I see that John had posted another response, and I have to agree with what he has written.  Happy woodworking, all!

 

[nickao]

What is weird every router bit I have(and drill bits) are always a bit small, but never a tad large, interesting.

I prefer a cutter be smaller than larger for the router bits(if they can not be exact), that can be made up.

I can see where the 20.25 mm would aggravate you.

 

[festooltim]

When i make new tops or accessories i use MDO not MDF.  I use the original top as a pattern then use a big plunge router with a 1/2" spiral up bit clamping  them together carfully plunge threw the pattern and let the smooth part of the bit rub around the hole, i haven't measured them but the clamping elements fit good and snug.

 

[danrush]

John / Corwin,

Thanks for your input.  I've been a carpenter for better than 25 years, but I don't consider myself a woodworker, not yet.  Just starting that part of my life. 

I'm still trying to wrap my brain around the tight tolerances that you say are a required starting point.  I don't disagree...  just haven't signed on yet. 

I'll ponder the thoughts you've shared, and I'm sure we'll talk again soon.

Thanks, Dan

 

[bionicus]

For the hell of it I just made a bunch of holes with this bit for the first time. With the LR32 system and OF1010 set at a low speed my results were perfect. In 3/4" MDF my Qwas dogs easily fall into place with absolutely zero slop once seated. It's true that the holes are a hair larger than the diameter of Qwas dogs but the tapered shoulder of the dogs definitely removes any play side to side. They just don't move at all. I suppose if I was looking for a friction fit I might have been be disappointed but as it is I couldn't be more satisfied.

 

[Corwin]

For the  of it I just made a bunch of holes with this bit for the first time. With the LR32 system and OF1010 set at a low speed my results were perfect. In 3/4" MDF my Qwas dogs easily fall into place with absolutely zero slop once seated. It's true that the holes are a hair larger than the diameter of Qwas dogs but the tapered shoulder of the dogs definitely removes any play side to side. They just don't move at all. I suppose if I was looking for a friction fit I might have been be disappointed but as it is I couldn't be more satisfied.

I didn't know that Steve's Qwas dogs had tapered shoulders, so, since Michael also has the Qwas dogs, that may (or may not) work for him.  Since I made my dogs to fit my tables, I didn't put a taper along the shoulders that would center the dogs in a larger hole.  My guess is that Steve did this to accommodate any variation between customer's tables.

 

[JeromeM]

Has anyone tried one of these?

I bought one while selecting wood at Hearne Hardwoods and just tried to use it to make MFT style holes in a large cutting table. I'm very disappointed.

First off it wants to wander. If the router isn't clamped in position the hole will not be perpendicular to the surface.

Second, even if the router is clamped securely in place the hole will be at least .25mm oversized. Even with a very light scoring cut the circle created is 20.25 mm.

I do use it. It has been perfect. That is as long as my jig is correct the thread is "20mm hole on a 96mm grid system (MFT top style)"
http://festoolownersgroup.com/member-projects/20mm-hole-on-a-96mm-grid-system-(mft-top-style)/msg78004/#msg78004

I can't check the size just now but the clamping elements and B&D dogs fit perfectly.

 

[John Stevens]

I'm still trying to wrap my brain around the tight tolerances that you say are a required starting point.

Well, they're required for me  [embarassed]  That's 'cause I have zero hand skills.  Can't play a musical instrument or a ball-sport to save my life.  All thumbs when it comes to hand tools.  Then there are guys like my late stepfather.  He was trained in the fine arts, and he could sketch, paint and sculpt.  He made his living repairing furniture with a combination of hand and power tools.  I don't know if he ever took a measurement, but worked instead by eye, shaping and trimming to meet whatever odd angles or dimensions were required.  I did some finish carpentry with him from time to time--moulding and a staircase.  You probably are able to work like he did.  I'll never be able to do that.  Some guys can throw a 70mph fastball, some guys can throw a 90mph fastball, and then there are guys like me who are happy just to get one over the plate at any speed, with no batter in the box.

Regards,

John