Turning Tool And Facing Tool Questions

[Joe Pitz]

Hello All,

Since I do not have a DRO on my lathe or dial indicators. What is the correct procedure for turning to a shoulder and then facing the shoulder.

I start out facing the end of the stock with the facing tool, then I switch to the right hand turning tool to rough out the O.D. (this forces me to change the angle of the tool holder) Then I have to switch to the facing tool again, which causes me to have to change the angle of the tool holder again. When I attempt to then match the correct O.D. I have problems holding the same dimensions at the shoulder, or if I have to increase the depth of the shoulder I end up messing up the O.D.

Also question on the new tool holders, Is is true that the new indexable tool holders have the geometry to both face and turn without having to change the tools?

Thanks

Joe

 

[RJSakowski]

When I have to turn to a precise shoulder, I grind my tool with an acute angle (around 75 deg.) and orient it so that I have relief both parallel and perpendicular to the spindle axis. That way I can both turn and face with the same tool setting.

I rough turn, stopping not quite at the face of the shoulder and when I am nearly at my final diameter, take a finish facing cut. I then make my final finish cut on the diameter. For diameter settings, I use the cross feed dial and mike when I get close. I then make differential cuts based on the mike readings. For the shoulder face, I set up a carriage stop or I set the compound up parallel to the spindle axis and use the compound dial to indicate position.

 

[JimDawson]

I assume you are using insert tools. If you use a tool that has less than a 90 degree angle, you can face and turn with the same tool without moving the tool post.

I normally just use a cheap (from Harbor Freight) AR-8 brazed carbide tool and grind a little more clearance on the nose so the angle is less the 90 degrees. I own a set of cheap insert holders, but I've only used them about 2 times. I would rather just grind to shape I want for the job.

 

[Joe Pitz]

Thanks RJSakowski,

I have started learning how to grind hss tools, let us just say, my efforts are not going good. I watched tubalcain's videos, but he free hand grinds, there is no way I am ready for that.

Thanks

Joe

 

[Joe Pitz]

Thanks JimDawson, do you have a diamond wheel or do you use a green wheel? I hear it is hard to grind carbide without chipping it?

Joe

 

[RJSakowski]

Thanks RJSakowski,

I have started learning how to grind hss tools, let us just say, my efforts are not going good. I watched tubalcain's videos, but he free hand grinds, there is no way I am ready for that.

Thanks

Joe

I free hand grind my tools as well. It helps to mount the tool bit in a holder to give you a better grip and to better judge the angle that you are grinding. You will get good at it with a little practice. A final hone with a whetstone will give you a keen edge.

Bob

 

[RJSakowski]

Thanks JimDawson, do you have a diamond wheel or do you use a green wheel? I hear it is hard to grind carbide without chipping it?

Joe

I rough grind my carbide tools with my Carborundum grinder and use a small diamond wheel to finish, honing with a diamond stone. The carborundum grinding is brutal and leaves chips in the carbide, hence the final grind on the diamond wheel. I do this because I don't want to use the diamond wheel for large removal of stock. Not the best way but it works.

 

[JimDawson]

Thanks RJSakowski,

I have started learning how to grind hss tools, let us just say, my efforts are not going good. I watched tubalcain's videos, but he free hand grinds, there is no way I am ready for that.

Thanks

Joe

Thanks JimDawson, do you have a diamond wheel or do you use a green wheel? I hear it is hard to grind carbide without chipping it?

Joe

Free hand grinding just take little practice, keep in mind the tip and the left side of the tool ( for a right hand tool) is doing all of the work, everything else is just clearance. The angles are not critical. If the tool grind does not produce the desired result, then try again with slightly different angles.

While I do have a tool grinder with green wheels, I normally just use my cheap Chinese bench grinder with with a standard aluminum oxide gray wheel. You just have to push a little harder. On the other hand, I do a lot of things that aren't ''normal'' IMHO, as long as shop safety practices are observed, anything goes in machining. There is no ''right way'' to do an operation as long as the part comes out the way you want it to.
.
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[Joe Pitz]

Thanks Jim and Bob,

I purchased 36" of 3/8" cold rolled steel square bar stock. This is my practice material. I will try free handing.

Joe

 

[JimDawson]

Joe, you might be better served by purchasing some 3/8 HSS tool blanks. That way you can test your grind as you are learning. Even after grinding tool bits for about 50 years, I still make a trip back to the grinder if the shape I ground doesn't do exactly what I want.