Dovetail shaped hole with a drill bit

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Project by kiefer posted 03-24-2016 02:25 AM 2871 views 3 times favorited 30 comments Add to Favorites Watch

Joe Lyddon ask me to make a video of my dovetail drill bit and post it after I made a comment on Todd Klippingers blog on pegged dovetails .
Here are a few pictures of the idea and patented proto type tool and dowel configurations I designed .
I hope you can tell from the pictures how this works but if not just ask and I will answer any questions ASAP .
This type of hole is not new and used to be done by drilling a hole first and then enlarging the bottom with a spoon bit and later with a router bit but what I wanted is a tool that could do this in one operation to make this feasible and efficient to use and also have fasteners as seen in picture #5 and #6
Here is the link to the video
I hope you enjoy and would appreciate comments .


-- Kiefer

30 comments so far

View DocSavage45's profile


8637 posts in 2892 days

#1 posted 03-24-2016 02:45 AM

Wow Klaus,

Wonder what a cat scan of your brain would reveal? LOL! Very impressive sir!

-- Cau Haus Designs, Thomas J. Tieffenbacher

View doubleDD's profile


7487 posts in 2093 days

#2 posted 03-24-2016 03:06 AM

Klaus, I would of never expected to see a second set of cutters coming out at the tip. I watched with anticipation and kept stopping the video to see if I could guess the secret. My jaw dropped to the table when I saw those second set of cutters coming out. It took a couple sleepless nights you say? I’d still be awake. This is one of the most impressive inventions I have seen in a long time. Very clever my friend.

-- Dave, Downers Grove, Il. -------- When you run out of ideas, start building your dreams.

View drewpy's profile


806 posts in 1407 days

#3 posted 03-24-2016 03:37 AM

Klaus, that is fantastic. I didn’t know what to expect when I stated the video, even after looking at the diagrams. I am impressed. Also, nice display of your shop sign you made a few months ago. Looks great.

-- Drew -- "The greatest wealth is health".

View hoss12992's profile


4045 posts in 1943 days

#4 posted 03-24-2016 04:00 AM


-- The Old Rednek Workshop

View Woodwrecker's profile


4163 posts in 3625 days

#5 posted 03-24-2016 04:33 AM

Klaus my friend.
I don’t know how you can fit that much brain in one head !
Nice work as usual.

View shipwright's profile


8000 posts in 2848 days

#6 posted 03-24-2016 04:34 AM

Good thinking. I’ve seen this before. Have you posted it here or mentioned it maybe a year or two ago?
It’s a wonderful bit of design work. Kudos!

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees.

View Jim Jakosh's profile

Jim Jakosh

20743 posts in 3155 days

#7 posted 03-24-2016 04:47 AM

Klaus, you are a genius!!!!!!!!!!!!!


-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View Joe Lyddon's profile

Joe Lyddon

10146 posts in 4102 days

#8 posted 03-24-2016 04:49 AM

Klaus… I told you so!...

Fantastic design, job, EVERYTHING!

Looks great!

The price for that bit just be enough to Choke a Horse! :)

COOL way to go!

Looking forward to seeing more on the subject!

You are simply FANTASTIC!

Thank you very much,

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: ... My Small Gallery:"

View Andre's profile


1921 posts in 1856 days

#9 posted 03-24-2016 05:02 AM

Amazing, remember you telling me about your patent. Making the expanding dowels to insert should be simple enough?

-- Lifting one end of the plank.

View helluvawreck's profile


31654 posts in 2916 days

#10 posted 03-24-2016 08:27 AM

Klaus, that is an amazing tool. I would think there should be a market for that and I hope that the whole endeavor works out well for you.

helluvawreck aka Charles

-- helluvawreck aka Charles,

View Dutchy's profile


3003 posts in 2218 days

#11 posted 03-24-2016 08:34 AM

I have worked more than 25 years for a big european tool maker (drills, routers, knives, shapers, saw blades and so on) This company was about 100 years ago the inventor of the slot mortise bits. In my working career I have sold and disigned a lot of tools. That is why making tools has still my interest.

This drill disign from you Kiefer is one in the ingenious category. My compliments. Sorry to hear you had sleepless nights.

The way one of my customers did it was to hydraulic crimping the end of the stick before it was put into the hole. For far as iI can remeber he did not use a wedge. After more than 20 years the connection still stuck (hope you understand what I mean).

After all I’m curious what steel did you use?


View jaykaypur's profile


4017 posts in 2458 days

#12 posted 03-24-2016 09:53 AM

Excellent design and I hope you get the due rewards from this. How long has this idea been in your head…..from first thought to actual prototype?

-- Use it up, Wear it out --------------- Make it do, Or do without!

View eddie's profile


8565 posts in 2664 days

#13 posted 03-24-2016 10:29 AM

very cleaver,

-- Jesus Is Alright with me

View jbschutz's profile


542 posts in 2741 days

#14 posted 03-24-2016 10:43 AM

Klaus, thanks for the invention…...when will it be on the market? You are one amazing guy!
You are still the reigning “mad scientist” of the LJ group.

-- jbschutz

View adrianpglover's profile


50 posts in 1573 days

#15 posted 03-24-2016 11:41 AM

That’s a really interesting idea. Very nicely done on the video too. Do you have the patent number? I’d be interested in reading through some of it. My few patents thus far are electrical engineering related, so I’d like to read one or two from another interest of mine.

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