Search found 423 matches
- Tue Feb 06, 2024 10:12 am
- Forum: Milling Machines
- Topic: Ring for a Troyke graduated in minutes
- Replies: 13
- Views: 1071
Re: Ring for a Troyke graduated in minutes
An arcminute is a very small angle. (One arcminute at 100 yards is a displacement of only 1.047 inches.) Just how often will you machine something where an angle must be known to that accuracy? If you mark out your 4 degree ring every 1/4 degree you only have to scribe 16 lines; if every 1/5 degree ...
- Fri Feb 02, 2024 12:08 pm
- Forum: General Discussion
- Topic: Drilling a .25mm hole.....any advice?
- Replies: 15
- Views: 1020
Re: Drilling a .25mm hole.....any advice?
...snip... I machine .03125" endmills often in the mil without issue at 4200RPM but to handfeed the quill with this drill I don't think I am capable, it's not soft enough to feel what's going on, hence why I want to do it on the lathe. If I recall there's an adapter though for mills for this a...
- Fri Feb 02, 2024 11:30 am
- Forum: General Discussion
- Topic: Drilling a .25mm hole.....any advice?
- Replies: 15
- Views: 1020
Re: Drilling a .25mm hole.....any advice?
Drills that small need to turn really, really fast... .25 mm = .01 inch With, say 200 sfpm for brass, the recommended speed would be... rpm = 200 * 12 / (π * 0.01) = 76,394 rpm You'll never get close to that with any conventional lathe. Even a Cameron micro drill press can't spin that fast although ...
- Sun Dec 17, 2023 1:50 pm
- Forum: Lathes
- Topic: Thread chart recovery - old Italian lathe.
- Replies: 5
- Views: 10707
Re: Thread chart recovery - old Italian lathe.
You're right; sorry, I missed the reference to the quick change box.
- Sun Dec 17, 2023 10:50 am
- Forum: Lathes
- Topic: Thread chart recovery - old Italian lathe.
- Replies: 5
- Views: 10707
Re: Thread chart recovery - old Italian lathe.
Once you know: A number of teeth on gear fixed to spindle B number of teeth on gear fixed to leadscrew C pitch of leadscrew it's simple arithmetic to compute the carriage movement (which equates to pitch cut on workpiece) due to any gear combination between spindle and leadscrew gears.. Alternativel...
- Sun Oct 29, 2023 9:36 am
- Forum: General Discussion
- Topic: Inherited Vintage Machinist tools
- Replies: 21
- Views: 6275
Re: Inherited Vintage Machinist tools
No, it's not a micrometer. They look like this... https://www.amazon.com/Mitutoyo-103-260-Micrometer-Baked-Enamel-Graduation/dp/B001C13U8K/ref=sr_1_2_mod_primary_new?keywords=mitutoyo%2Bmicrometer&qid=1698589573&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sr=8-2&th=1 The pictured device i...
- Sat Oct 28, 2023 3:45 pm
- Forum: General Discussion
- Topic: Inherited Vintage Machinist tools
- Replies: 21
- Views: 6275
Re: Inherited Vintage Machinist tools
Third picture upper left corner triangular thing = planer gauge; some of the threaded parts lower left may be extenders for it middle right bar with two attached cylinders = sine bar; probably home made bottom right bar with "swan neck" = spring back threading/cutoff tool for lathe; bends ...
- Sat Oct 28, 2023 9:43 am
- Forum: General Discussion
- Topic: Inherited Vintage Machinist tools
- Replies: 21
- Views: 6275
Re: Inherited Vintage Machinist tools
The large, black clamp-like thing center right in the photo... is a lathe dog. It's used to drive a workpiece that is being turned between centers on a lathe. The jaws clamp around the work and the tail is inserted into a hole in the rotating faceplate to transmit the motion to the work. Below and t...
- Mon Oct 23, 2023 12:11 pm
- Forum: General Discussion
- Topic: Drilling Holes In 3mm Aluminium Using Forstner Bits
- Replies: 28
- Views: 9473
Re: Drilling Holes In 3mm Aluminium Using Forstner Bits
I mentioned this earlier in this thread but recently discovered a video that demonstrates it more vividly than I could in words... https://www.youtube.com/watch?v=cAGiuXOKKi8 It's a very old trick which I learned from my Dad. Nevertheless, it's worth keeping in mind for those cases where an expedien...
- Thu Oct 12, 2023 12:53 pm
- Forum: General Discussion
- Topic: Drilling Holes In 3mm Aluminium Using Forstner Bits
- Replies: 28
- Views: 9473
Re: Drilling Holes In 3mm Aluminium Using Forstner Bits
Unibit is the best advice but, if you must use an ordinary twist drill, drill through a small patch of shop towel or similar; that will give you a nice clean, circular hole instead of the typical tri-lobal, burr encrusted mess one typically gets with a bare drill in sheet metal. Don't forget to secu...
- Sun Sep 10, 2023 12:27 pm
- Forum: The Junk Drawer
- Topic: I found it!
- Replies: 16
- Views: 5651
Re: I found it!
Today I was fiddling around trying to figure out a threading problem and wondered that if the thread progression is 2,3,4,5,6,8, and 10, why aren't there numbers 7 and 9? Idiotic nomenclature systems like this were invented to make life difficult for apprentices and thus make their supervisors appe...
- Sun May 21, 2023 8:51 am
- Forum: General Discussion
- Topic: Another round of "what the heck is this?"
- Replies: 11
- Views: 1599
Re: Another round of "what the heck is this?"
The error in the angle set with the sine bar is a function of two other errors - the error in the sine bar length and the error in the stack height. The equation that describes the sine bar is: sinA = H/L where: A = desired angle H = stack height L = sine bar length (distance between roll centers) U...