Can hinge boring bit really be used in a router?

[amt]

I have a question about this Festool bit: http://www.festoolusa.com/power-tool-accessories/routers/router-bits/8mm-shank/hinge-location-bits/euro-hinge-boring-router-bit-20mm-diameter-491072

I am wondering if this is really meant for a router.  It does state, "router bit", but it's the only one of its kind (20mm) that I can find which states so.  Every other brand of hinge boring bit or forstner bit state that they should used in a drill only.  Is this type of bit something unique to Festool? 

I would like to make some MFT holes, but I would much prefer to use a plunge router instead of a drill, since I would likely have far more control in getting a hole perpendicular to the surface.

I also heard that this bit is not actually 20mm, but something like 20.2mm.  Anybody know for sure the actual diameter?

 

[gkaiseril]

It is listed under the 8mm router bits. Those here who have built MFT tables tend to use drill boring bits.

 

[rmwarren]

I have one and used it in my OF 1400 to bore MFT type holes, works fine. The holes came out just a hair larger than those in my MFT, but not enough to cause a problem using my dogs.

I would recommend plunging 3-4 times for each hole, to clear chips and dissipate some heat.

RMW

 

[amt]

Thanks for the responses.  I would like to have no slop at all, so maybe I will try a forstner bit (for an exact 20mm) and not a hinge boring bit.  Anyone have pics of a drill jig they used?

 

[mouppe]

I used this very bit to bore two rows of holes along my 1 1/2" maple workbench top. I used the LR32 holed rail to give me precise spacing. It worked excellently, without any slop or run-out. A drill couldn't have done any better at all.

I can't see how the flat base of a router plunging in a single plane could give you a more accurate perpendicular hole than a drill wobbling all over the place?

Go for it I say.

 

[tbellemare]

It is a router bit and it works quite well

Tom

 

[amt]

Just to clarify, the slop I was referring to would be due to the slightly larger diameter of the hinge boring bit and not the boring technique. There is of course some room for error when using a hand held drill, and if I choose to use a drill, I would certainly need a guide to keep it perpendicular and ideally lock it in to the exact position on the table top.

if I could find a router-suitable boring bit that really is exactly 20mm (and not 20.2 or whatever the festool one is) that would be great.  The options out there that are 20mm are either not really suited for plunging/boring, or they are not suited for a router at all.

 

[ccarrolladams]

If the difference between a 20.0mm and 20.2mm dia hole is so critical, and in the real world of table tops that has not been proven to be the case, why not take your Festool cup hole 20mm nominal bit to a qualified grinding service and have to reduced to exactly what you want?

Festool has never confirmed the actual method they use to create the MFT holes. It is assumed a CNC machine is involved.

There are several ways to program a CNC machine to accurate make hole as far as placement and diameter. In metal working much depends on the nature of the metal and the size of the hole. Often a slightly undersized hole is drilled and then enlarged to exact size with a reamer. Another approach is to bore the hole using a program which uses an undersized up-spiral end mill set to move in a circular motion after the initial drilling.

Reamers are seldom used in wood fabrication, and they do not work well at even the minimum rotation speed of a conventional router.

 

[semenza]

    I think that you will have a better result with the 20.2mm router bit in a router than with a 20mm bit in any type of drill set up. The added accuracy and stability  of the router will probably keep the hole closer to 20mm than the drill with an actual 20mm bit.  If you go with the 20mm drill bit you will need to check it to see if it is exactly 20mm .... because  who knows what tolerance it might be manufactured to ??  Also the .2mm will most likely gain or lose by humidity changes so going exactly 20mm might have some problems too.  [2cents]

Seth

 

[bkharman]

I have used this bit on about 400 holes. It fits my Qwas, my Parfs, my bench dogs, my Precision Dogs and all fit really well.

I would say that the Precision dogs have the nicest fit in both the stock MFT and my custom holes.

My .03.

 

[tbellemare]

I'm not sure why you think this bit, (Festool 491072), results in a hole bigger than 20mm but I'd be very curious to see the evidence.

There are a number of reasons why a hole can be bigger than the bit. I just measured one to the best of my ability across the cutters and it was just under 20mm.

I have sold tens of these bits and nobody reported back that the holes were over 20mm. Perhaps there's someone on this forum that can comment, including technique employed?

Tom

 

[ccarrolladams]

Tom, what I can say is that the Festool nominal 20mm hinge cup bit for use as part of the LR32 system correctly fits the intended hinges, as does the similar 35mm bit.

Personally I doubt that when designing the 20mm bit Festool considered its use making DIY MFT tops. Yet, I am told it works well doing so.

Before I owned CNC machines I felt my time was expensive enough I was saving buying MFT replacement tops. Once I had the CNC machines and space for large tables I do use the CNC machines during periods when otherwise they are not booked for paying projects.

 

[mouppe]

Here you go Tom.

Further to my earlier post, I use my Festool clamping elements and other 20mm dogs in both my MFT holes and the holes I bored in my workbench with the bit under discussion, and the fit is the same in both.

 

[tbellemare]

Thanks, RL...

That's what I've been thinking.

Tom

 

[amt]

I found the 20.2mm discovery from here: http://festoolownersgroup.com/festool-jigs-tool-enhancements/mft-top-20mm-holes/

However, if you are measuring just under 20mm, then that is good enough for me.  I'll place an order shortly.

Thanks,

-Andrew

 

[bkharman]

Again, never had a fit issue with that bit, my 1400 on low speed, good MDF and the lr 32 to get the right placement.

Best to you and merry Christmas.

 

[mikeneron]

I used this bit with my OF 1400 router and the LR32 kit and holy rail to make a MFT style top so I could get square cuts easily.  Worked great! Now with the QWAS dogs in the rail and some 20mm bench dogs in the holes, it's a no brainer to make square cuts...wish I had done this awhile ago.

I find there is a very very small amount of play with the holes and whatever I am putting into them (QWAS rail dogs, parf dogs, MFT clamping elements). I did measure the holes in another thread and  they came out to 20.10 mm.  Even if the holes were 20.20 mm, how much is that really going to affect the accuracy? My guess isn't much, but it's just a guess.  Would be curious to find out if someone has too much time on their hands

 

[amt]

Thanks for all of the help.  I just ordered the bit from tool-home.

FYI, I have a couple of the Incra tracks and the positioner (all metric), so I may try to use them to locate all of the holes.

 

[tbellemare]

If you want, amt, I can bring my bit over for you to test and if you like the hole, I'll have a new one for you also.

Tom

 

[amt]

Tom, no need.  I have too much going on for the next three days, so there is no rush at all.  Thanks for the offer, though.