2020 POTD Thread Archive

[Downunder Bob]

Well done.

 

[FOMOGO]

Thanks Bob, I'm sure it would have been easier to just order some new o-ring stock, but I need the practice, and any time I get with my machines is time I really enjoy. Cheers, Mike

 

[Bi11Hudson]

Just to put things in perspective, or why I hang out on a machinist board when I'm not a machinist. The enclosed photo mostly shows my incompetance with focusing the camera. The subject is a US penny, with a couple of screws laying on it. There is a Nr 2X3/16 and below that a Nr 0 X1/8. To describe one is usually like talking to a wall, a photo (bad as it is) allows someone not familiar with small parts to perceive the size.

This is usually what I work on and don't post because it's not something interesting, except to folks in the hobby who have their own web sites. The screws are not "machine" screws, more like sheet metal screws. The normal size "0" threads are 80 TPI, this one is 48 TPI, for soft metal and dense wood. "ZAMAK" being the soft metal. The penny shows the relative size of the many parts.

I do do machine work, and deal with tight tolerances. But when I'm working on "normal" sized stuff, things are "to fit", not necessarily to manufacturer's drawings. My hobby is small, and hard to describe to an 'outsider". It doesn't show well, but there is a spring in the "knuckle" of the coupler to the right.

I have been in my hobby for many years. (>50 yrs) Acquired a UniMat in 1969 to do some of it, not very well I think. When I started making turnbuckles for a tractor, I needed to work larger material. (1/2-20) That's what got me into "normal" sized machining. Most of you fellows do beautiful work. What I do isn't well seen or showed off. Keep up the good work. . .

Bill Hudson
.​

 

[extropic]

Just to put things in perspective, or why I hang out on a machinist board when I'm not a machinist. The enclosed photo mostly shows my incompetance with focusing the camera. The subject is a US penny, with a couple of screws laying on it. There is a Nr 2X3/16 and below that a Nr 0 X1/8. To describe one is usually like talking to a wall, a photo (bad as it is) allows someone not familiar with small parts to perceive the size.
<snip photo>
This is usually what I work on and don't post because it's not something interesting, except to folks in the hobby who have their own web sites. The screws are not "machine" screws, more like sheet metal screws. The normal size "0" threads are 80 TPI, this one is 48 TPI, for soft metal and dense wood. "ZAMAK" being the soft metal. The penny shows the relative size of the many parts.

I do do machine work, and deal with tight tolerances. But when I'm working on "normal" sized stuff, things are "to fit", not necessarily to manufacturer's drawings. My hobby is small, and hard to describe to an 'outsider". It doesn't show well, but there is a spring in the "knuckle" of the coupler to the right.

I have been in my hobby for many years. (>50 yrs) Acquired a UniMat in 1969 to do some of it, not very well I think. When I started making turnbuckles for a tractor, I needed to work larger material. (1/2-20) That's what got me into "normal" sized machining. Most of you fellows do beautiful work. What I do isn't well seen or showed off. Keep up the good work. . .

Bill Hudson
.​

Bill,
Isn't it strange that your post about your uninteresting hobby has left me with a number of questions? Could it be that there is something in there that's interesting to me? Maybe, I just didn't get the joke?

My first question is, do you want some suggestions regarding taking better (in focus) pictures?

Second, I'm not familiar with the "Nr" nomenclature for the small screws. I Googled "Nr screws" but no help there. What does the "Nr" mean?

 

[Bi11Hudson]

Sorry, it's my first experiment with a new video camera. I'm still in the "read the manual" stage for something that has a great focus beyond 3 inches. I'll replace/repost the photo when I get more time on the camera. Or maybe re-rig out the microscope. . .

"Nr" is my interpretation of "No" for "number". The word doesn't have an "o" in it and I've never understood why "No" is the accepted abbreviation. I've used Nr as the "corrected" abbreviation for years on my drawings. A "No" 0 or "aught" screw is 0.060 inch in diameter. A way, if nothing else, to leave a signiture hidden in "plain sight". It makes more sense to me since there is an "r" in the word. A lot of what I do doesn't make sense until you look closely. And too, I don't like (or trust) Google, for political reasons. . .



.

 

[Janderso]

I decided to remake my mill stop completely out of steel. I had made one with most of the parts aluminum, but I found there was more flexing in the arm than I cared for. So, I remade it with 1018 steel and used FreeCAD and LinuxCNC for some of the parts. The base part has "keys" to mate with the T-slots were mostly cut by CNC, but I had to finish it manually. FreeCAD had some weird motions doing 45 degree passes and it left a lot of material.

I used CNC to cut the two large bolts patterns on the top rather than knurl them for gripping. I used a 1/8" radius 5/8" diameter corner rounding end mill to round over the 1/4" arm so it fits the slider slot perfectly without filing it square (which I did on the first one).

Disassembled:
View attachment 325361
Together:
View attachment 325362
In use:
View attachment 325363
Another in use:
View attachment 325364

This looks great!!

 

[extropic]

Sorry, it's my first experiment with a new video camera. I'm still in the "read the manual" stage for something that has a great focus beyond 3 inches. I'll replace/repost the photo when I get more time on the camera. Or maybe re-rig out the microscope. . .

"Nr" is my interpretation of "No" for "number". The word doesn't have an "o" in it and I've never understood why "No" is the accepted abbreviation. I've used Nr as the "corrected" abbreviation for years on my drawings. A "No" 0 or "aught" screw is 0.060 inch in diameter. A way, if nothing else, to leave a signiture hidden in "plain sight". It makes more sense to me since there is an "r" in the word. A lot of what I do doesn't make sense until you look closely. And too, I don't like (or trust) Google, for political reasons. . .

Thank you. I understand now. Why is "No" the conventional abbreviation? More info here.

 

[Nogoingback]

It never occurred to me that I could actually break a hacksaw, but as it turns out it's possible. This saw is, I think, a Chinese copy of a
Lennox design which I bought at a garage sale last year. There's a nut inside the handle that takes the load when tightening blade
tension. The threads stripped on the nut, which appears to be cast from Zamak. I had a small chunk of 303 square bar left over from
a previous job that was perfect for its replacement. Offending nut on the left.



I like to support indicators on the QCTP whenever possible. Since I don't have a mill, I keep stuff simple, and this indicator holder
is about as simple as they get. Cut it out from 1/2" flat bar, cleaned it up with the belt sander and drilled and tapped one hole.
Easy.

 

[Tim9]

My 1939 South Bend Lathe has a pronounced register on the spindle directly behind the 1-1/2” 8tpi threads. This register or collar depending on your preference of descriptions is about 1.800” and about 5/32” in depth. Because of this, my chucks from the little 3-1/2’ bed lathe never properly fit my newer 1947 SouthBend 9” lathe which is. 4-1/2’ bed. This war production South Bend Model A ...part # 444Z .... has no register on the spindle.
I’ve been using the lathe because just had so many other projects.... finally checked it and the 3-jaw chuck was running @ 12 thousandths out. I knew it was out a little but 8 thousandths is just unacceptable.
So....either I install bushings in the chuck backing plates....or I add a register to the lathe. I went with making a bronze register using 660 bearing bronze. Using the bigger Clausing I made an oversized bushing that was about 1/4” in depth and 1.9500 “ In width.
It was about 2 thousandths undersized ... 1.498” ...to press on the spindle . Pressed it on spindle using red Loctite and used the tailstock and a bigger collar to press on the spindle .... letting it cure overnight.
After then turning it to size .... I have a register matching the smaller 1939 SB. Checked and it’s running true in the below picture.

 

[Tim9]

FWIW....once Loctite cured...I installed a dead center in the spindle... preloaded the spindle with a shaft drilled and mounted between centers.... and turned the register to size. Here’s a picture of that setup....but taken earlier when checking the backing plate of that chuck which was 12 thousandths out of specs. I couldn’t believe it was that far out. But it was.