Paul a second term student is rebuilding a small Craftsman engine lathe. He is fabricating a faceplate for this lathe using a 6 inch diameter pipe flange and 1 inch nut heli-arced onto the flange.
Here Paul is using a piece of paper that mic'ed 0.004 inches to accurately "pick up" the surface of the faceplate for the proper dept of cut. The T slots are for the standard 5/16 T-nut and are specified as 3/8 inches wide. The 3/8 end-mill will cut a 0.510 deep slot.
The first T-slot cut! the cutter was located to cut the bottom of the "T" exactly 0.500 inches from the face of the plate. This gives a 0.010 clearance under the cutter. It is not an optical illusion that the slot appears off center to the hole in the background. The clamp to the left in the picture was too close to the cut and the "nose" of the spindle and/or collet moved the clamp and the part over on the second pass. This caused the invoking of the ancient Chinese machining god "Ah S**t." Faceplate is still fully functional, and students learned valuable lesson about checking tool path /clamp clearance.
Completing the last cut. Note that clamp is totally clear of the tool path, and we are not clamping "air" which tends to bow or warp the part.
Paul with his almost finished face plate. He is planning on adding several drilled and tapped holes for fixturing and attachment of sub-plates to avoid damage when machining though holes. Paul also is modifying 3/8 carriage bolts. If the heads are slightly reduced in diameter and height and the sides milled/ground to the width of the wide part of the 'T" slot these make excellent light duty fixturing components.
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last updated by GmcD on 19-Mar-11 19:30
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