Search found 423 matches

by mklotz
Tue Feb 06, 2024 10:12 am
Forum: Milling Machines
Topic: Ring for a Troyke graduated in minutes
Replies: 13
Views: 781

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 ...
by mklotz
Fri Feb 02, 2024 12:08 pm
Forum: General Discussion
Topic: Drilling a .25mm hole.....any advice?
Replies: 15
Views: 612

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...
by mklotz
Fri Feb 02, 2024 11:30 am
Forum: General Discussion
Topic: Drilling a .25mm hole.....any advice?
Replies: 15
Views: 612

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 ...
by mklotz
Sun Dec 17, 2023 1:50 pm
Forum: Lathes
Topic: Thread chart recovery - old Italian lathe.
Replies: 5
Views: 9809

Re: Thread chart recovery - old Italian lathe.

arborist wrote: Sun Dec 17, 2023 1:31 pm
mklotz wrote: Sun Dec 17, 2023 10:50 am Once you know:
I think you missed D) the ratios in the 10 speed Norton gearbox attached to the machine.

Actually, to fit your list properly, it should not be D but the letter that is between B and C.
You're right; sorry, I missed the reference to the quick change box.
by mklotz
Sun Dec 17, 2023 10:50 am
Forum: Lathes
Topic: Thread chart recovery - old Italian lathe.
Replies: 5
Views: 9809

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...
by mklotz
Sun Oct 29, 2023 9:36 am
Forum: General Discussion
Topic: Inherited Vintage Machinist tools
Replies: 21
Views: 5722

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...
by mklotz
Sat Oct 28, 2023 3:45 pm
Forum: General Discussion
Topic: Inherited Vintage Machinist tools
Replies: 21
Views: 5722

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 ...
by mklotz
Sat Oct 28, 2023 9:43 am
Forum: General Discussion
Topic: Inherited Vintage Machinist tools
Replies: 21
Views: 5722

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...
by mklotz
Mon Oct 23, 2023 12:11 pm
Forum: General Discussion
Topic: Drilling Holes In 3mm Aluminium Using Forstner Bits
Replies: 28
Views: 8380

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...
by mklotz
Thu Oct 12, 2023 12:53 pm
Forum: General Discussion
Topic: Drilling Holes In 3mm Aluminium Using Forstner Bits
Replies: 28
Views: 8380

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...
by mklotz
Sun Sep 10, 2023 12:27 pm
Forum: The Junk Drawer
Topic: I found it!
Replies: 16
Views: 4773

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...
by mklotz
Sun May 21, 2023 8:51 am
Forum: General Discussion
Topic: Another round of "what the heck is this?"
Replies: 11
Views: 1511

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...