2017 POTD Thread Archive

We have a slitter at work that has no thrust bearings so the two shaft MAY move side to side. So I suggested making a couple of blocks that would preload via a plunger that is spring loaded using some spring washers and an adjusting screw. The plungers sit in the centers that are already on the shaft ends. All lathe work except for the band saw to cut the 2" aluminum blocks. The thread is 11/16 X 18, yes 18! So turning, threading, reaming, knurling, drilling, boring, etc. Basically just about the whole gamut. I supplied the tap and knurling tool.

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I needed to turn the head down on a #8 - 32 machine screw and tried fitting in one of my ER40 collets but it wouldn't fit so I tried chucking it in the 3 jaw but that didn't work. If I left the jaws loose enough to not damage the threads when clamping down, the screw would spin when trying to cut the head and damage the threads anyway. If I clamped the screw harder then the threads would get damaged too. Then I had an epiphany (well maybe just a bright idea). Just drill and tap the end of a piece of scrap and put the screw in there and voila problem solved. Sometimes its the simple things that make your day.

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I've also been contemplating making ER4o collet blocks (square and hex) so I can do simple indexing but I haven't got there yet. Today I needed to index a part 180* to make some flats and was about to haul out the RT and 3 jaw chuck when it hit me. I made an R8 collet block for my end mill (end) sharpening jig and I could use the ER40 R8 setup in that. Man that was waaaaaaaay easier than loading the RT onto the table.

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The process of turning the diameter of a SHCS head above, reminded me of a job I did today. Over the past several weeks I've been drilling and tapping on my mill some 4-40 threads. Like as not, the tap slips in the keyless chuck i'm using.Thoughts: if it were larger diameter and not hard it probably wouldn't slip. I picked a piece of 3/16 OD SS tubing, drilled it out to fit the tap body, (.140 for 4, 5 and 6 diameter taps) Cut it off 3/4 long, put the tap in and mashed the end square on the tap. (I made a pair of dies for this some time ago, never put them in service.)
In all fairness, I had to Locktite the tap in the sleeve, it kept pulling out when I reversed the quill and lifted it.
But it doesn't slip any more.
 
I needed to turn the head down on a #8 - 32 machine screw and tried fitting in one of my ER40 collets but it wouldn't fit so I tried chucking it in the 3 jaw but that didn't work. If I left the jaws loose enough to not damage the threads when clamping down, the screw would spin when trying to cut the head and damage the threads anyway. If I clamped the screw harder then the threads would get damaged too. Then I had an epiphany (well maybe just a bright idea). Just drill and tap the end of a piece of scrap and put the screw in there and voila problem solved. Sometimes its the simple things that make your day.

I had a similar problem lowering the profile of the head of a hex head machine screw for clearance. I just screwed it in a coupling nut and chucked it in the 3-jaw.
 
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