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  1. Conrad Hoffman

    Filament printers- probably better than you think!

    When we bought our Bambu printer there weren't many examples of the sort of things we wanted to print. Well, we're over the moon with the unit and here's an example of a small and reasonably precise part. It's a gib used in a tiny stage. We use a lot of them and had been machining them out of...
  2. Conrad Hoffman

    Help me edit a ppt slide on surface roughness

    I'm doing a Powerpoint on surface finish measurement. I have one slide that's a pet peeve with me. It concerns all the reasons not to do min/max Ra values. I've just cut and pasted it here, but it should be readable. Curious if anybody has opinions, agrees or disagrees that setting lower limits...
  3. Conrad Hoffman

    OT- Torn rotator cuff- any words of wisdom?

    I think I've got a torn rotator cuff on my right shoulder. Trying to get a appointment with the doc. I know it's a popular machinist injury due to the location of controls on the mill and down feed on the grinder. It's bad enough I don't think I can shift my car and sleep is, no pun intended, a...
  4. Conrad Hoffman

    How precise is a shaper?

    I doubt I'll ever have or have access to a shaper, but I was doing something recently that just screamed out for one. I needed to put a very small V-groove on the surface of a part. It needed a sharp bottom. I ground a tool and fastened it in the mill spindle, then drove the part underneath the...
  5. Conrad Hoffman

    Xometry Quality Lately?

    We've had pretty good results using Xometry for small quantity prototype parts... until recently. Almost everything we've received lately has be unusable due to burrs, bad geometry and totally out of control chamfers. Our parts are small, under 1" in most cases, but not that difficult. Were we...
  6. Conrad Hoffman

    Is compensating for tool wear a "thing"?

    Not a CNC guy here, so maybe a dumb question. Does one compensate for tool wear? I don't really grasp this because it seems if a tool is worn enough to need compensation, it's what I'd call dull, and in need of replacement. Seems like the finish would be going bad. How does it work in the "real"...
  7. Conrad Hoffman

    Restoring Starrett 257C surface gauge

    Picked up a nice, but quite rusty, Starrett 257C surface gauge at the yearly Pageant of Steam in Hopewell, NY. Disassembled and gave it a good soak in Evaporust. It looks pretty good now, with little pitting except on the bottom of the base. Two questions- 1) What's a good final treatment for...
  8. Conrad Hoffman

    UR3e base location callout

    The location holes in the base of a UR3e robot say Ø5 FG8 +0.024 +0.006 depth 8.5 min. WTH is FG8 as I can't seem to look it up anywhere? I'm assuming they mean the hole is somewhere between 24 and 6 microns larger than 5 mm, but I'd really like to see a proper reference. Also, where do you get...
  9. Conrad Hoffman

    Trouble mounting inserts on SECO face mill

    Maybe I'm just a klutz but have a new small SECO 5-insert face mill for the Bridgeport. It seems very difficult to get the 8-side inserts screwed on so they're at exactly the same angle and height. I would have thought the back and two faces would guarantee that, but there's a certain amount of...
  10. Conrad Hoffman

    Tiny Spot Welding Issues

    We spot weld tiny photo-etched stainless steel parts using a fairly decent programmable welder (Miyachi HF25). This has worked fine for many years. We recently switched vendors for the raw sheets (yes, to the cheap place) and are having welding issues. The new sheets are a few microns thinner...
  11. Conrad Hoffman

    Torch hardening small punches and the like- self tempering?

    I was hardening some small tooling made from 7/8" diameter 52100. All I really wanted hard was a turned down tip. Turned out OK, but it later occured to me that the stored heat in the back end of the thing was similar to the 375F tempering I did. Would tools like that be "self-tempering" because...
  12. Conrad Hoffman

    4-start thread on manual lathe

    I want to repair something that has a buggered 4-start worm. I think the part was purposely soft so it would fail, rather than take out the worm gear. Or it was just cheap. Anyway, it looks like I need to cut a 2.66 tpi thread on my manual Logan. OD is about 1/2". I wouldn't dare try it in...
  13. Conrad Hoffman

    How to make sharp points?

    We need to put tapered points on 1/8" SS rods. About half an inch of taper, down to a moderately sharp point. We presently turn them, but this requires near perfect tool height. Are there any other ways people do this? There must be some process used to make pins and needles. The old steel...
  14. Conrad Hoffman

    Popular Science ad

    Looking at an old April 1936 Popular Science magazine I noticed this ad. Price looks good but I bet it was a lot of money for people back then. Hey, it says you can run it from a lamp socket!
  15. Conrad Hoffman

    Wax or something to replicate surface roughness?

    I have a very good surface profilometer, but it's a fixed unit and takes a moderately small and low mass sample. I also have a large aluminum plate, several feet square that I have to measure. Is there any accepted "stuff", like a wax or resin, that I can replicate the finish with, then measure...
  16. Conrad Hoffman

    Optical Measurements (Profiler), Trust & Traceability

    The profiler in question is basically a collimated light source and a camera system. You hold something in the beam and the camera end sees and measures what is essentially the shadow. If the object is a round pin, I can be highly certain that the light is being cut off tangent to the round...
  17. Conrad Hoffman

    Joe's Little Tap Wrenches

    My friend Joe has retired, but back when he was working in our shop he would make up these little tap wrenches. We do a lot of very small threads, #0-80 and M1 stuff. Very often a pin vise type wrench (I like the Starretts) has too much mass hanging too far out, but not as much turning torque or...
  18. Conrad Hoffman

    Dilution for Simple Green?

    I know some of you use Simple Green. About to try some on a bunch of parts (1" x 2" x 8") that are covered with oil (Buttercutt). I might use a dishpan or might fill up the ultrasonic cleaner. Any recommendations on what dilution might work, if any? Yes, I could just go try it, but a starting...
  19. Conrad Hoffman

    Robotic Inspection Video

    Another division of the company I work for (full disclosure) just did a video on robotic inspection. Brief, but I thought they presented things in an entertaining manner - Q-Span Gauging Systems on Vimeo
  20. Conrad Hoffman

    OT: Jaguar XKSS documentary

    Our PBS station just ran this. If you work with metal you'll find it interesting, should they happen to run it in your area. They recreated, from scratch, the 1950s XKSS street version of the race car. https://www.channel4.com/programmes/jaguar-xkss-a-supercar-is-reborn

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