Need to find flat bottom drill bit

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kauaiknifeworks

New Member
I have been desperately looking for a flat bottom counter bore bit in 3/32 pilot and 5/32 shaft for folders. Anyone have any luck or any direction where to go. I have been making my own using a 5/32 bit, and flat grinding the smaller hole. Just want to find the right tool
 
A centercutting endmill will have a flat bottom.

You might try Enco or MSC for the counterbore.
 
I don't think you will get the results you want with a squared drill bit. It will walk and not stay centered. You need a pilot to keep the tool centered. Take a look at http://www.use-enco.com/CGI/INPDFF?PMPAGE=69 They have different size counter bores and different size pilots. Word of caution make sure the pilot shank diameter of the counter bore is the same as the shank diameter as the pilot. There are other sources but Enco seem to be decent quality for a fair price. I can generally do about 20 knives before they get to dull and I need to change them out. Unless I use them on Carbon Fiber then they are junk for titanium after 1 use.
 
I agree with Alan's suggestion....interchangable pilot counterbores are really you're only "good" option. The problem with them is that they are only available in HSS or Cobalt, and if you are counterboring Ti....they will only do 2-3 sets of counterbores before they are wrecked. I don't know if he has anymore available, but not long ago, Steve Kelly (TiConnector.com) had some custom made carbide counterbores.... they are pricey, but well worth it. If the enco interchangeble pilot type doesn't work for you, check with Steve.
 
First let me say I think for what you are trying to do then advice from Ed and Alan is probably what you are looking for. However the title brought this to mind, check out this video!

https://www.youtube.com/watch?v=qwuSBJFa5uM

For softer materials this flat bottom bit will work and work well. I had needed to drill a flat bottom hole in a wood handle, so I checked out some counter bores and the prices were way more than I wanted to spend for what I was doing. I Googled drilling a flat bottom hole and that video pops up. So I After watching this I went to the drill index box I had that was full of roached bits I had never sharpened. Selected the size I needed and ground it just like the video shows. To date I have used these flat bottomed bits on aluminum, wood, and plastic, as well as mild steel. If you drill the pilot hole first,.............they will absolutely work on softer materials! Used in a drill press or mill on softer material it will work without wandering. Stop and think about, the hole you piloted is already drilled to size and depth except for the shoulder the point of the bit left! Chuck up the flat bottom bit and it will drill it out with a flat bottom with no wander! I doubt his would work for hard materials, but on softer materials it does the job well and the cost is only one roached bit you probably have on hand already!
 
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