Checking My Nuts
(05-03-2015, 02:38 PM)Highpower Wrote: A good question to ask oneself is "If I do this, and something goes wrong - how badly am I going to hurt myself?"

That is always a good question to ask oneself. Cool
Smiley-eatdrink004
DaveH
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Got the new blank ready yesterday and this evening I switched the gears to cut a 10TPI thread. Then I chucked up a piece of aluminum and test cut a V thread. Good to go.

Oh, and I tried every single number on the threading dial one after the other and they all synced with the thread so "1-8" on the chart really means 1, 2, 3, 4, 5, 6, 7 and 8.  Big Grin

Ed
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(05-11-2015, 04:44 PM)EdK Wrote: Oh, and I tried every single number on the threading dial one after the other and they all synced with the thread so "1-8" on the chart really means 1, 2, 3, 4, 5, 6, 7 and 8.  Big Grin

Ed

That's good to know - Thumbsup
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DaveH
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Just read through this whole thread, I was wondering why I had missed it previously then realised it is cunningly concealed in the 'milling machines' section even though it is all about cutting acme threads on the lathe...at least the last 8 pages or so are!

I have just gone through this whole process myself, as briefly described in my other post. Made the new 1" 5tpi crossfeed screw then cut the bronze nut, plus a spare. I had all sorts of problems with the first attempt at an internal acme thread, could not keep the tool bit mounted in the boring bar- turns out I had cut the clearance angles in the opposite direction, thinking for some reason that the internal threading tool had to be ground the same as the external threading tool. It was only after taking the nut out of the chuck that I could see I had been rubbing the back side off the thread the whole time.
After grinding the tool the right way around, and loctiting the toolbit into the boring bar, cutting the internal thread was super easy. I did the whole thing with plunge cuts off the cross slide, with a dial indicator set up as a poor-man's DRO. I started off by drilling to 3/4", then used the acme threading tool on a fine feed to bore to the minor diameter- I then knew exactly where the tool was and how much further to cut when doing the actual thread.

I've been thinking about incorporating some sort of backlash adjustment into my nut, thinking about those spring-loaded arrangements someone linked to- seems to me that they would result in the tool being held against the work by a spring- either when turning or boring- which would be worse than leaving the backlash in.

Also, I wasn't game to grab anything on the dial except the number 1 while doing this thread. I'm too easily confused.
Lathe (n); a machine tool used in the production of milling machine components.

Milling Machine (n); a machine tool used in the production of lathe components.
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(05-11-2015, 10:58 PM)Pete O Wrote: Just read through this whole thread, I was wondering why I had missed it previously then realised it is cunningly concealed in the 'milling machines' section even though it is all about cutting acme threads on the lathe...at least the last 8 pages or so are!

I guess it depends upon the context.  The repair is for a milling machine but I see your point.  This is why I read all the posts.  Whilst some may not interest me, I am often surprised by what I learn or discover in a thread that may not have caught my attention based on the title or the category posted.  Also, as one of the mods here, I believe I am obliged to read every post as part of my job.  I certainly don't want to jeopardize my health benefits or lose my parking spot Big Grin
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or that big end of year bonus check!
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Failure number two. I'm not sure what I did wrong but it's on to number 3.

What's the best way to measure the minor diameter of an external acme thread?  17428

Ed
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if its course enough the end of a depth mike will fit in, major dia minus twice the thread depth. Or the end of your caliper not as accurate but close.
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Greg
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Thanks Greg. I'll give those a try. I really need to characterize this bastard thread so I can get it right this time.

Ed
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As best as I can measure, the depth of the thread is to spec at about .060".

I'm thinking my tool needs some tweaking.  Chin

Oh well, this will have to wait while I get back to the secret project that Greg is expecting. Luckily it's all lathe work.

Ed
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