# Give Your Parting Blade a Tune-Up, Plus Turning With a Parting Blade



## BobWarfield (May 4, 2008)

I use these little HSS steel parting blades:







They're made on a surface grinder, though I buy mine on eBay from seller samsws, and are usually listed as "Cut-Off Parting & Grooving Mini Lathe Tool". The price for 3 was $16, and I've found they work great. You can just pop them into a regular toolholder. Not as heavy duty as the Aloris above, but they do make a much finer cut, so I use them for smaller diameters. 

While I love the little parting blades mentioned above, I find they benefit from a little "tuning up." Here's how I do the tune up:






First, use the radius on the edge of your grinding wheel to put a little positive rake in the blade. This greatly reduces chatter on a lot of materials. Easy does it, don't take too much off!






Next, take on of those inexpensive pocket diamond hones and use it to make the tool really sharp. I QCTP holder with the tool on its side on a flat surface, and stand the hone up on it's side. A couple of swipes as shown are all it takes to make the blade really sharp!






This last tip is not really necessary for parting, but I somethings use my parting blade as a turning tool, for example on my Verburg Steam Engine Team Build connecting rods. A radius like this is essential for such cuts. Put the radius on the side you'll be moving into the cut. The radius shown gives you a tool that can take shallow turning cuts moving from tailstock to spindle...


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## BobWarfield (May 4, 2008)

Turning with a parting blade makes it easy to get nice square shoulders if you need your smallest OD between two larger OD's. Here, we are about to plunge the blade and we'll be turning to the left shoulder that's visible. Don't try too much depth of cut. A sure sign of trouble is a build up of material on the part at the cutting point. Eventually something will break if that's happening--take a shallower cut! For this little brass part 0.010 to 0.015 on the dial (0.005 to 0.0075 actual DOC) worked well and gave a decent surface finish...






Nice square shoulders due to the parting blade. Got a few left to do there!

Cheers,

BW


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