Festool 20mm router bit

[Maumee Mike]

okay guys    I went and bought this bit so that I could add 20mm holes to a workbench which I plan on using as an extension for my MFT when breaking down full sheet goods...so I used the LR32 which by the way is pretty slick and punched the holes in the top...well to my chagrin  I tried the quas dog and lo and behold there is a little play in it and is not as tight a fit as in the MFT dog holes...methinks the holes in the MFT are not quite 20mm or the router bit is more than 20mm diameter...anyone else have this problem?

 

[Wuffles]

Which router bit? The Forstner or the spiral? I've used the spiral with the Qwas dogs and it seemed alright to me.

 

[Maumee Mike]

forstner    didn't know there was a spiral    Marino website only showed the forstner  do you know where I can get the spiral?

 

[Wuffles]

Everywhere you like in the UK, not sure about USA.

Part number is 490947

However, I heard that the Forstner is good for dog holes normally too. Perhaps you have a duff bit or dog.

 

[SittingElf]

Some dealers here carry that bit....  Toolbarn says 10-14 days to ship....shipping cost there.

Here's a link to ToolNut: (Unfortunately it's out of stock there at the moment)

HSS 12x20 Bit

Better solution is this bit. Looks like a forstner, but is specifically designed for the purpose you are looking for. Not cheap though and 8mm shank.

491072 - Carbide Euro-Hinge Boring, Plunge Router Bit, 20 mm Dia

Cheers,

Frank

 

[SittingElf]

Here's a pic of a review on Amazon for the 491072.  Specifically addresses your application! [big grin]
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Cheers,
Frank

 

[rst]

I've made multiple tops with mine...at least 600 holes...fantastic system!

 

[abcd123]

Everywhere you like in the UK, not sure about USA.

Part number is 490947

However, I heard that the Forstner is good for dog holes normally too. Perhaps you have a duff bit or dog.

490947 is 12mm in diameter...

 

[SittingElf]

Everywhere you like in the UK, not sure about USA.

Part number is 490947

However, I heard that the Forstner is good for dog holes normally too. Perhaps you have a duff bit or dog.

490947 is 12mm in diameter...

Not available in the USA right now. No one has it.  And it's a 20mm bit, not a 12mm, which is the shank.

Frank

 

[GarryMartin]

And it's a 20mm bit, not a 12mm, which is the shank.

That's not correct Frank. It is a 12mm diameter cutter with an 8mm diameter shank. You need 490951 for the 20mm version.

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[jeh]

I've made multiple tops with mine...at least 600 holes...fantastic system!

[member=25351]rst[/member] - Did you use an existing MFT top as a template? I am thinking about making one for my workbench to compliment my MFT's. Also, which bit (part #) did you use?

 

[Wuffles]

My fault if it's wrong, I googled 20mm spiral festool and that's what it came back with. I should have checked.

 

[rst]

I used an LR32 system, with Festool 491072, Incra T tracks, and Rip Dogs stops and guides.  I made 96mm and 192mm gauge blocks for spacing.

 

[GarryMartin]

My fault if it's wrong, I googled 20mm spiral festool and that's what it came back with. I should have checked.

No ones fault Wuffles. Festool router bit labelling can be confusing at the best of times, and to be honest, some retailers don't help when they get it wrong too! That's why I posted the router catalogue images - they're very clear about how the bits are labelled and I'm sure will help people out.

I've not tried the spiral cutter personally, but I have the 20mm "hinge borer" and it works very well; nice clean holes.

 

[timberwolf]

I'm thinking of making an mft top, which bit do I need?  I was ready to order the festool forstner bit, but after this thread I am confused. The spiral bit is not available, has been discontinued.

 

[Wuffles]

I'm thinking of making an mft top, which bit do I need?  I was ready to order the festool forstner bit, but after this thread I am confused. The spiral bit is not available, has been discontinued.

Has it? I might have to buy up old stock in that case.

 

[Stone Message]

okay guys    I went and bought this bit so that I could add 20mm holes to a workbench which I plan on using as an extension for my MFT when breaking down full sheet goods...so I used the LR32 which by the way is pretty slick and punched the holes in the top...well to my chagrin  I tried the quas dog and lo and behold there is a little play in it and is not as tight a fit as in the MFT dog holes...methinks the holes in the MFT are not quite 20mm or the router bit is more than 20mm diameter...anyone else have this problem?

One of the potential problems with a plunge router cut, particularly large diameter ones like this, is that it is almost impossible to hold the router rigid enough to guarantee that the hole is perfect. Next, if you take a sample of sizes of many makes of router and drill bits you may see slight size variation.

In my experience the Festool cutters are spot on.

Peter

 

[Ostap]

My 491072 measures 20.1mm on cutter head.
Adding some play from my router plunge rods results holes that are 20.2+ mm in size.
Those are not suitable for 20mm dogs, but is ok for clamps. No experience from spiral bit, but I would go with spiral first.

 

[myer84]

My 491072 measures 20.1mm on cutter head.
Adding some play from my router plunge rods results holes that are 20.2+ mm in size.
Those are not suitable for 20mm dogs, but is ok for clamps. No experience from spiral bit, but I would go with spiral first.

I agree. I'm also in the process of making my own table top and invested on the same router bit and LR32 rail. After doing some test cut holes, I also noticed a slight play when using parf dogs. I haven't measured the dogs or bit, but I'm sure the bit is the culprit since I've tested two different sets of parf dogs and small dogs.

I wonder if that slight play will show in my final cut when doing 90 degree cuts. Any thoughts on this? If not a big deal, I won't bother buying the spiral bit

 

[Stone Message]

I have gone through all sorts of tests and checks with Parf Dogs and drills. For those of you with a 20 mm Zobo in original condition do a test drill and then see how the Parf Dog fits.

Peter