Which counterbore for folder bearings?

G

gudspelr

Joined
Jul 1, 2013
Messages
451
Well, I just made a pretty good mess of a Ti liner that had a lot of work into it. Making a folder with bearings for the first time and had gotten an interchangeable, piloted counterbore a while back, knowing I wanted to have it for the future. Using it on steel went okay. Then, I went to my Ti liner. That went less okay. Long story short, I got it too hot and mangled it.

So, which counterbore do you use? This one was a somewhat cheap cobalt one with an interchangeable pilot. Do you guys like to have a carbide tipped one? They’re pretty dang expensive, which made me think that’s how I ended up with the cobalt one.

I remember seeing a thread a while ago where someone used an endmill or something similar to spot the location for the pivot, then swap out with a 3/8” endmill, in effect making a work around for the piloted counterbore.

Last, any suggestions on the best way to counterbore Ti? Do you like to use oil or some sort of coolant? Does it depend on the material of your endmill/counterbore? Thanks in advance for any help.


Jeremy
 
I use coolant. About 400rpm lots of pressure. If it rubs too much it will work harden. You need to always be cutting to avoid it. You want to use carbide tipped counterbores. The larger the diameter the more pressure required.
 
FWIW I use a gage pin to locate the pivot hole, lock the frame/liner down and replace the pin with a solid carbide end mill.

Works well and fairly quick. And the end mill lasts a good long time.
 
I have only tried it once before, but had good luck with a HSS counterbore (I make folders in metric, so I doubt a source will help much). I drilled the correct pilot size in blade and liners and drilled dry, careful to not let it skate and work harden the liners.
 
You must log in or register to reply here.
Back
Top