hammerscale

Amateur Machinists' Tools, Techniques and Materials

Archive for June, 2011

Cutoff Tool Geometry

Posted by hammerscale on June 19, 2011

 

A good grind on a high speed steel (HSS) cutoff tooling is essential. A fresh ground razor sharp edge with the below shape works well to produce a clean chatter free surface.

Tooling sold for cutting-off comes ground with a beveled cross section for clearance. As usual, a relief angle is hand ground, either straight or curved, to give clearance below the centerline of the work piece, while a second angle, across the narrow width of the blade, is ground with a leading edge (exaggerated a bit in the illustration) that provides a clean and complete separation of the part without twistback or catching on the tooling.

The angle is eyeballed at the grinding wheel at roughly 30 to 45 degrees.

 

Cutoff Profile

Cutoff Profile

 

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The Second Safety Rule is…

Posted by hammerscale on June 6, 2011

Continuing to build upon my initial concept; 

 

Rule #2

When using the lathe tailstock, always remove the tooling as soon as you’re done with it. With your attention at the lathe spindle, your right arm/hand is guaranteed to contact whatever sharp edge is mounted in the tailstock, – tap, drill bit, reamer, etc.

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Avery Labels, got to love ’em….

Posted by hammerscale on June 5, 2011

Labeled Fasteners

Labeled Fasteners

 

Labeled Fasteners part 2

Labeled Fasteners part 2

 

 

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Small Shop Project

Posted by hammerscale on June 1, 2011

Machinist's Screws

Machinist's Screws

These old style machinist’s clamp screws are a step above socket head cap screws when it comes to style as well as substance.   The square head is a bit more accessible in tight quarters, and the integrated washer is certainly a bonus.   I’m always in need of machine screws of varying lengths for work holding on the mill table, and may make a few for the shop.  The furthest on the right is my first attempt, in 41L40 steel.   The knurling I added as a touch of ergonomics,  but the washer under the head should be much larger.   Back to the drawing board….

Profile for Screw

Profile for Screw

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