Keeping BB taps sharp
#1
Guest
Posts: n/a
Mentioned: Post(s)
Tagged: Thread(s)
Quoted: Post(s)
Keeping BB taps sharp
About to send some of my cutters in to get sharpened and was wondering if any of you guys have used a diamond hone or something similar to touch up the cutting edge on BB taps. I've heard of this as an elbow grease machinist method. A couple of machinists I know also recommended a Dremel with a grinding bit that matches the rake, but I think I'm too clumsy to risk that on a $160 tap . I have a good set of kitchen knives that I'm able to keep nice and sharp with the occasional honing, was wondering if this logic also applied to taps. The facing mills and reamers I'll leave to a tool grinder, I think sharpening those is more tricky.
#2
Banned
Join Date: Aug 2005
Posts: 5,115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times
in
1 Post
You can stone the face that is radial (not the threads). You need to keep the stone flat and work the whole face confident that it will eventually erode to the point that the edge is sharp. If you bias towards the edge, you will "dub" it, which means change the rake angle of the edge creating a negative rake. As with all honing you really want to hone while the edge is sharp. If you dull the edge sufficiently it will require regrinding, which can be done by hand or machine, but requires that more material be removed and raises the stakes if you aren't fully confident.
#3
Guest
Posts: n/a
Mentioned: Post(s)
Tagged: Thread(s)
Quoted: Post(s)
You can stone the face that is radial (not the threads). You need to keep the stone flat and work the whole face confident that it will eventually erode to the point that the edge is sharp. If you bias towards the edge, you will "dub" it, which means change the rake angle of the edge creating a negative rake. As with all honing you really want to hone while the edge is sharp. If you dull the edge sufficiently it will require regrinding, which can be done by hand or machine, but requires that more material be removed and raises the stakes if you aren't fully confident.
#5
Banned
Join Date: Aug 2005
Posts: 5,115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times
in
1 Post
Be careful what tool grinder you leave it to, it's getting ugly out there. I guess you are fine if you send them to one of the bike guys.
The surface I am talking about is flat, and you apply a flat stone to it. The other surfaces are the same shape as the BB cups you are going to insert into the BB, You don't touch those.
In case you wreak it, here is how you can make your next one:
https://frets.com/FRETSPages/Machinin...p/19mmtap.html
The surface I am talking about is flat, and you apply a flat stone to it. The other surfaces are the same shape as the BB cups you are going to insert into the BB, You don't touch those.
In case you wreak it, here is how you can make your next one:
https://frets.com/FRETSPages/Machinin...p/19mmtap.html
#6
Guest
Posts: n/a
Mentioned: Post(s)
Tagged: Thread(s)
Quoted: Post(s)
I think I know what you're talking about. Still might be a little too tricky for me, I'm no machinist. I've used McKenzie tool grinding in Portland once in the past and they seem to do a good job (they specialize in bike and odd machining tools). They do all the tool grinding work for Andy Newlands (Strawberry Bicycles) who makes HSS mitering cutters. I've looked into TIN coating for my tools; at the rate that I use them, they probably wouldn't need sharpening for several years. Kinda expensive though.