Finished up the screw for Darren by milling the 6mm wide x 20.25mm long keyway and putting in the 5mm hole called for on his print.
The keyway was a good exercise for me with the conversational Prototrak control on my Alliant milling machine. Because I don't have a 6mm end mill, I used a 4-flute solid carbide 13/64" (0,2031") end mill I had kicking around and used cutter diameter compensation to make it cut 6mm (.2362") wide. It took a couple of passes to get right, largely due to not having a reliable method of gauging the width. In the end I used the 6mm shank of a 1/8" solid carbide drill I have as my gauge, making that a very snug fit. I presume that a 6mm key will be on the small size, so it should fit with a tap in.
The chuck that came on my dividing head was a nice 6 1/4" 3-jaw. Unfortunately, the size of it prevents a bolt from being used in the front slot when mounting the DH on the mill table. I have a 5" 4-jaw that has a backing plate with a hole just a bit smaller than the minor diameter needed for the M30 x 3 spindle thread. Easy to use a carbide boring bar to take it to the right size.
When it came time to cut the internal thread, I needed to make a split sleeve to mount my 1/2" boring bar with the threading bit. Cut a piece of 3/4" CRS, drill and ream to 1/2", slit on the horizontal mill - done deal.
Pretty standard threading job, after I had swapped out some gears to cut a metric thread.
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When the thread was 'visually' complete, I tried it out without removing the plate from the 4-jaw on the lathe. Since a 10 1/2" is a bit too heavy to spin off and screw onto a dividing head, I had to set the DH up to the hole on the lathe and crank it into the hole. It takes quite a while to crank in a 40:1 DH. I'm just glad it was already the right size. Nice snug fit.
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After the fit was proven, I cut a 1/4" deep section at major diameter. The backing plate tightens up very nicely on the DH spindle.
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The end result is that I can attach the DH to the mill table much more easily.
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Thanks Ken - I really appreciate your time and efforts in making this for me. I'll get you the height for the 5mm pin shortly.
Mike - nice work on the backing plate.
That looks a job well done Mike
DaveH
Mike, I envy you that tilting dividing head! Nice work indeed, getting it fitted with a good chuck.
I'm not actively looking for one of those, but I will eventually come across one and it would be on my "must have" list.
nice job on the backing plate, at 10.5 inches it would make my little 4 inch DH look like a toy.
The 10 1/2" is the 4-jaw on the lathe. I was using it to hold the 5" backing plate for machining.
Got some shop time today because it started off raining. With most of Darren's elevation screw & nut project done, I had to take some time to work on the motorcycle parts for Neil (expat.)
Two castellated nuts for axles I'd previously made. I got one completely done, the other still needs the slots put into it.
The turned, drilled, tapped and hex milled blanks:
The finished one:
Hey Ken, are you going to make the cotter pins for them as well?
Nice job!
Tom