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loose nut
08-01-2011, 03:19 PM
I am currently making the breech ring for a 1/6 Th scale model of a WW1 artillery piece, and since this was a 4 day weekend for me, it seemed like a good time to get some work done.

First off, I had threaded the end of the breech ring that screws onto the barrel and them turned and threaded a mandrel so that the breech ring could be threaded onto it for more turning. Next I had to remove the mandrel after shaping the OD of the ring to make a threaded test piece (I needed this to size the non-standard thread of the breech screw) to use while I was boring and threading the breech threads. Now comes the fun bit.

Fri. didn't get out to the shop, Sat. I was busy with other things, didn't get out to the shop. Sunday finally out in the shop, turning the test piece but I double threaded it. Pissed off I left the shop. Mon. back into the shop turning the test piece, everything looking good (should have known better at this point) and when I was finished it was a nicely threaded piece.

At this point I needed to place the first threaded mandrel back onto the lathe, I had turned a register on the OD and end face of it so that it could accurately be placed into a 4 Jaw at this point but I had also marked out where the # 1 jaw (originally turned on a 3 jaw chuck) was and put it back into the 3 jaw just to see how close it was. On all the register faces there was a 0.0005" or less movement. Couldn't ask for a better situation. There should have been alarm bells going off at this point.

So at this point I had the breech ring back onto it's mandrel in the 3 jaw set up as close to perfect as most of us could ever get and when I was going over the drawings to get them ID dimension for boring out the breech thread I realized that the threaded test piece I had made was the wrong size.

Starting all over again next weekend.

Tinkerer
08-01-2011, 03:26 PM
Yep had a few of those days.... at least yours was not a customer job with a deadline of hours. I'm sure the next part will be perfect... ;).

garagemark
08-01-2011, 03:32 PM
Sometimes you eats the bear..... sometimes the bear eats you. I feel your pain.

[sigh]

Mark

Carld
08-01-2011, 04:59 PM
Yep, had that happen and sometimes it was on a customers job:eek: :mad: . It always amazes me that my mind can convince me that I am doing it right when everything is going the wrong way :confused: . :rolleyes:

DFMiller
08-01-2011, 07:20 PM
loose nut
That is not good news. Next one will be quicker to make.
I spent BC day fitting my ER collet holder to my Myford Clone. If I had some M8x1.25 x 16 I could see how much it wobbles.
Dave

NzOldun
08-02-2011, 04:09 AM
I am currently making the breech ring for a 1/6 Th scale model of a WW1 artillery piece, and since this was a 4 day weekend for me, it seemed like a good time to get some work done.

First off, I had threaded the end of the breech ring that screws onto the barrel and them turned and threaded a mandrel so that the breech ring could be threaded onto it for more turning. Next I had to remove the mandrel after shaping the OD of the ring to make a threaded test piece (I needed this to size the non-standard thread of the breech screw) to use while I was boring and threading the breech threads. Now comes the fun bit.

Fri. didn't get out to the shop, Sat. I was busy with other things, didn't get out to the shop. Sunday finally out in the shop, turning the test piece but I double threaded it. Pissed off I left the shop. Mon. back into the shop turning the test piece, everything looking good (should have known better at this point) and when I was finished it was a nicely threaded piece.

At this point I needed to place the first threaded mandrel back onto the lathe, I had turned a register on the OD and end face of it so that it could accurately be placed into a 4 Jaw at this point but I had also marked out where the # 1 jaw (originally turned on a 3 jaw chuck) was and put it back into the 3 jaw just to see how close it was. On all the register faces there was a 0.0005" or less movement. Couldn't ask for a better situation. There should have been alarm bells going off at this point.

So at this point I had the breech ring back onto it's mandrel in the 3 jaw set up as close to perfect as most of us could ever get and when I was going over the drawings to get them ID dimension for boring out the breech thread I realized that the threaded test piece I had made was the wrong size.

Starting all over again next weekend.
I know the feeling!!

A good few years ago my wife's agitator washing machine stared to give trouble and to get the spindle out I had to split the 2 nut holding the spindle tube to the base of bowl. No problem I thought, I'll just make another on my Pre-WWII 3 myford. Fortunately, had a suitable piece of 3/8 stainless plate left over from making the yacht winches (another story). Hack-sawed the plate to size - stainless is a right PITA to saw by hand, set up in the lathe, rough turned and bored, cut notches in the periphery to suit a 'C' spanner and finally, single point cut the thread inside the nut, to match the spindle tube - no QC box, no thread dial, no reverse switch. Didn't quite fit the first trial so re-setup and removed 2-3 'thou more. Still didn't fit so repeated this step. Still didn't fit. By now, I was thinking I wasn't going about this the right way. Checked all my measurements (again!) TPI was right, OD & ID of thread appeared to be pretty bang on - most puzzling.

Looked at the tube thread again to check it wasn't a double start and then the penny dropped!!. The tube thread was L.H. - a days work down the tubes.

Kept the nut for more than 20 years, just to remind myself, now and then.

NzOkdun

Oldbrock
08-02-2011, 10:44 PM
Been there, done that. 50 or so years ago boss said make four new chuck screws for the Niles four jaw chuck. Ends were forged and annealed. Mounted square in lathe and set up and made the four screws. Boss came along and said "Beautifull threading Peter but they are supposed to be LEFT HAND THREAD" He nailed them to the wall behind my lathe just as reminder to put my brain in gear before starting the machine.:eek: Peter

flutedchamber
08-03-2011, 01:13 AM
Loose Nut,

What happened to you has happened to everyone at some time or other in one form or other.

While it is a shame that it happened, next time the alarm bells will go off, but you will listen to them.

It's a learning experience, we never stop learning..and hopefully we catch our mistakes before they ruin our day.

Best of luck to you.:D

loose nut
08-03-2011, 07:33 PM
I know it happens and it isn't the first time for me but after a couple of days like that I feel like selling out the shop and taking up squirrel watching.

Less aggravation.

flylo
08-03-2011, 09:23 PM
Three weeks ago my Dodge diesel truck quit, then the LP fork lift regulator malfunction setting the floor of the shop on fire burning the hair off my legs. I was lucky & had a fire ext & put it out. Then the riding mower broke. The heat index has been 100+ every day.
This week things came together, everything's fixed & today I bought a great 10HP air comp for $50. It's cooling off & like is good. So things will get fixed & life will be better. Just makes you enjoy the great days.