Festool 20 mm hinge location router bit

[Michael Kellough]

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 have an assortment of sizes of QWAS dogs and even the largest diameter dog is way too loose to be any use in a hole drilled by this bit.

It's marketed as a hinge location bit. I've never used any hardware that would fit such a hole. Are the 20 mm hinges oversized? Is that why this bit cuts holes larger than it's stated diameter? Does the Festool 35 mm also cut larger than 35 mm?

 

[image132]

To my knowledge these are made for blum inset hinges. You get that router bit with the LS-32 hole drilling set. For the inset hinges it works perfectly I found, although I agree with the scorching. I thought maybe I was using it wrong. I never measured whether it cut 35mm perfectly but it seemed to fit the hinge very well.

You can see I used it here 6th picture down.

 

[tbellemare]

My 35mm bit, 491077, works quite well. I haven't tried the 20.

Tom

 

[ajones]

do you have a means of checking runout with the bit fitted in your router?

 

[bhendrix]

What is your router speed setting?  If I recall correctly, at cabinet training class in Lebanon, Brian suggested using slow speed and mild feed rate on the 35mm bit for routing/drill hinge holes.  Not sure if the same applies to 20mm.

 

[bionicus]

Just out of curiosity, were you using the router freehand or attached to the LR32 guide plate and rail?

 

[NVA_WW]

I've had great success using this bit with the LR32 kit.  I've made a couple of MFT-like tops using this combination.  I certainly wouldn't try it freehand unless you set up a jig that prevents the router from moving around.

 

[Rob-GB]

Michael, two things:-

1) The larger the diameter of the cutter the slower the rpm and feeed rate.

2) 0.25mm is a tolerance fit for euro type hinges, they are press formed cups.

One solution over the obvious.
As 0.25mm is tiny, a lick of the outer cutting edges with a diamond file or a DMT credit card size diamond plate would sort it.

Rob.

 

[Michael Kellough]

To answer some of the good questions asked...

I used the slowest speed first and moved up to medium. No difference noticed.
Burning was observed on the very first hole at the lowest speed with a somewhat aggressive plunge rate.
The scoring tips are bi-directional scrapers, they don't actually cut so they burn the wood until the chippers
come along behind and pry out the wood.

I used the router on the guide rail (an ordinary guide rail) to cut a series of holes and thats when I noticed that it wanted to wander. Even with a snuggly fitted guide rail stop/sled the bit tried to pull the router along. I trapped the sled between my fingers and got better results but if I were to try to replicate an MFT top I'd have to clamp stops on the guide rail to get perpendicular holes. Actually I'd use the LR 32 guide system since it provides positive stops without the need for clamps.

After I drilled the series of hoes and discovered that they are all too big I wanted to find ut exactly how big the hole was and figured with the movement I'd noticed on the guide rail I'd have to literally clamp the router to the table to be fair to the bit. So I used clamps to secure the base of the router to the table and carefully plunged through a sheet of 1/2" MDF. My calipers read 20.25 mm. I then tried again in a fresh location. Clamped the router and made a very light score (no chipping) and measured that to be 20.25 mm also.

The router is in good condition and the bit spins very nicely as far as I can tell by looking at it in a very bright light at various speeds. I can usually see signs of run-out even if I can't measure it and I didn't see any sign.

I'm interested in the suggestion to trim the bit down. The scoring teeth determine the OD and they are raised compared to the rest of the body of the bit. How would you go about it?

 

[Rob-GB]

I'm interested in the suggestion to trim the bit down. The scoring teeth determine the OD and they are raised compared to the rest of the body of the bit. How would you go about it?

The way I touch up the edges of shaper tooling, is too take it slow and take equal strokes of each edge, maintain a constant pressure. Use a vice to secure the bit firmly.
It may be a bit easier for me as I use handsaws that I sharpen myself, so keeping a constant pressure and file angle is a practiced job. I do this to some router cutters too.
HTH, Rob.

 

[fatroman]

I've got that bit and used it in the LR32 set up to do exactly what you are thinking of. In my case I used a cut down sheet of 3/4 ply to make a clamping station.

It worked fine, and have no problem using the clamping elements in the resulting holes.

But I just checked and the holes are roughly 20.20 mm, though they vary a bit in size from maybe 20.10 to 20.24

 

[Michael Kellough]

I've got that bit and used it in the LR32 set up to do exactly what you are thinking of. In my case I used a cut down sheet of 3/4 ply to make a clamping station.

It worked fine, and have no problem using the clamping elements in the resulting holes.

But I just checked and the holes are roughly 20.20 mm, though they vary a bit in size from maybe 20.10 to 20.24

Thanks for the feedback. I'll try the bit in a different router.

 

[greg mann]

Michael,

.2mm is too much to take off with a diamond file. You will make it worse. Double check the diameter over the scoring teeth. Since it is cutting 20.2mm and that it does not want to behave for you makes me think there might be something wrong with the grind. If it measures 20mm on the money that would confirm it is probably not ground correctly. You should not get burning and/or an unclean cut. FWIW, Rockler sells a 20mm carbide tipped Forstner bit with a 3/8 shank. I have used this with good results in a router with 3/8 collet after I shortened the shank.

 

[tbellemare]

Routers spin pretty darn fast for forstner bits.

Tom

 

[Michael Kellough]

Michael,

.2mm is too much to take off with a diamond file. You will make it worse. Double check the diameter over the scoring teeth. Since it is cutting 20.2mm and that it does not want to behave for you makes me think there might be something wrong with the grind. If it measures 20mm on the money that would confirm it is probably not ground correctly. You should not get burning and/or an unclean cut. FWIW, Rockler sells a 20mm carbide tipped Forstner bit with a 3/8 shank. I have used this with good results in a router with 3/8 collet after I shortened the shank.

That's what I thought too. If I mess with it I'll run it in the router against a diamond wheel
in a right angle grinder if I came assemble a suitable rig.

Before I begin to go to all that trouble I'd sure like to know from Festool if that bit is supposed to cut
a 20 mm hole or not. If it is specked at 20 mm and not merely marketed as 20 mm I'd like to know
how to get an in-spec replacement. If 20.25 mm is the best they can do I might try to grind it down
or see if one of my non-Festool routers has a 3/8" collet available.

 

[greg mann]

Routers spin pretty darn fast for forstner bits.

Tom

Agreed, but the bit Michael is using is essentially a Forstner, as is the 35mm hinge boring bit. I did specify the Rockler in the carbide tipped version, not HSS.

 

[greg mann]

Before I begin to go to all that trouble I'd sure like to know from Festool if that bit is supposed to cut
a 20 mm hole or not. If it is specked at 20 mm and not merely marketed as 20 mm I'd like to know
how to get an in-spec replacement. If 20.25 mm is the best they can do I might try to grind it down
or see if one of my non-Festool routers has a 3/8" collet available.

Did you caliper it over the spurs to see what size it actually is? Also, Bosch makes a 3/8 collet.

 

[Corwin]

Michael,

I have both the Festool 20mm hinge bit and the Rockler 20mm carbide-tipped bit.  Both measure right about 0.790" across.  But, with the router bit I get the same results that you have indicated.  However, with the Rockler bit in my drill press the holes are in the 0.790" to 0.792" range.  Go figure -- I would have thought that my drill press has more runout than my OF-1400.    [unsure]    The 0.790" bench dogs I made a couple years ago fit nicely into two of my MFT tops and a base for my fence that I drilled with that Rockler bit.

Good luck!

 

[danrush]

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

 

[John Stevens]

Hi, Michael.  Sorry to hear you're having trouble with that bit.  Hope at least your trip to Hearne was good in terms of wood--been there a few times and liked it.

FWIW, I have Festool's 20mm diameter "mortising" bit (no. 490972), and it works like a charm for boring holes for Festool MFT accessories.  Best of luck to you, hope your problem gets solved to your satisfaction.

Regards,

John