Author Topic: What bit for drilling ø20 holes in a custom size MFT?  (Read 1177 times)

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Offline kgp43

  • Posts: 2
What bit for drilling ø20 holes in a custom size MFT?
« on: November 21, 2020, 06:59 AM »
Hi,

I got question and hope one of you might be able to help me :)
Got a 1010 router and a 20 mm. bit (491072).

The diameter of the holes are way too big (ø20.2-20.3), the dogs can wriggle in the holes.
Also have the UJK Parf Mk II Guide System and the holes are a nice snug fit.

Changing the speed of the router does not change the diameter of the holes that much, they are still way too big.
Am I using the wrong bit? I read on this forum, that people use it with great success in MFT tabletops.



Regards,

Kenneth
« Last Edit: November 21, 2020, 07:09 AM by kgp43 »

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Online MikeGE

  • Posts: 264
Re: What bit for drilling ø20 holes in a custom size MFT?
« Reply #1 on: November 21, 2020, 07:25 AM »
Welcome to the FOG!
There are several threads here about this topic, and I think you will find the diameter of the HW D20 K8 (Festool 490971) is not suited for 20mm dog holes for the reason you are experiencing.  Apparently, the cutter is slightly larger than 20mm, so any attempt to use it for snug dog holes is doomed.  There are other cutters available that might work, but these are made for drills instead of routers.
I have the UJK Parf Mk II as well, and used it recently to cut 200 (10x20 grid) holes in a 1x2 meter top.  I can't find any fault with the Parf kit and am completely satisfied with the accuracy of the grid and the snuggness of the holes.  While making holes using the OF 1010 might be faster, having loose-fitting dogs defeats the purpose. 

Offline Peter Parfitt

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Re: What bit for drilling ø20 holes in a custom size MFT?
« Reply #2 on: November 21, 2020, 07:29 AM »
Hi @MikeG and @kgp43

Mike is right. Also, it is not possible to get the positional accuracy when using a router.

Peter

Offline kgp43

  • Posts: 2
Re: What bit for drilling ø20 holes in a custom size MFT?
« Reply #3 on: November 21, 2020, 07:45 AM »
Welcome to the FOG!
There are several threads here about this topic, and I think you will find the diameter of the HW D20 K8 (Festool 490971) is not suited for 20mm dog holes for the reason you are experiencing.  Apparently, the cutter is slightly larger than 20mm, so any attempt to use it for snug dog holes is doomed.  There are other cutters available that might work, but these are made for drills instead of routers.
I have the UJK Parf Mk II as well, and used it recently to cut 200 (10x20 grid) holes in a 1x2 meter top.  I can't find any fault with the Parf kit and am completely satisfied with the accuracy of the grid and the snuggness of the holes.  While making holes using the OF 1010 might be faster, having loose-fitting dogs defeats the purpose.

Thank you very much :)

I have an injury on my right hand, so using the UJK system hurts quite a bit - thats why I tried this approach instead.
Was really hoping that bit worked.

Offline Wood_Slice

  • Posts: 102
Re: What bit for drilling ø20 holes in a custom size MFT?
« Reply #4 on: December 02, 2020, 11:31 PM »
I have the Mark II guide as well and makes perfect holes. The dogs that come with the guide have a 19.95mm diameter when i measured with my caliper and fits very snug. Seems for every day dog use 19.95mm is too snug to remove easily which is why most aftermarket 20mm bench dogs try to be at 19.90mm.
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Offline Julie

  • Posts: 29
Re: What bit for drilling ø20 holes in a custom size MFT?
« Reply #5 on: December 03, 2020, 07:51 PM »
I prefer my dogs to be very snug. I buy the TSO close fit dogs and they measure 19.97 consistently. They have groves to make them easy to remove.

As for the dogs that come with the Parf guide system, I agree they are very hard to grip and remove, but the very close fit is required for accuracy of the hole grid. I drilled and tapped them and added a knob to make it easy to pull them out. Not only does it make removal easier, but when drilling the 20mm holes I just pull one dog and rotate the guide around the other dog 180 degrees. Then I put the dog in the new hole going through the guide. It make the process faster.