OldTools Archive
Recent | Bios | FAQ |
263893 | Brent A Kinsey <brentpmed@c...> | 2017‑11‑13 | Hot mic |
My S.I.L. Gave me a present today. A pristine Millers Falls 1 inch micrometer. https://brentpmed.wordpress.com/caught-a-hot-mic-2/ Brent Sent from my iPad |
|||
263900 | Claudio DeLorenzi <claudio@d...> | 2017‑11‑13 | Re: Hot mic |
Wow Brent, that’s gorgeous! What a great find- (both the son in law, and the Mike!) And that size is probably the most useful size. These are basically bullet proof, about the only thing that can go wrong is that you have to adjust the zero point. It’s really just a precision thread. I have some old Mikes - Lufkin, B&S, Starrett, and Moore&Wright, many of them old and abused, and they’re all still accurate. Did it come with a ‘standard’ ie a bit of steel rod of known length for calibration? My newer one has a plastic insulation on the standard, I guess to control for thermal expansion? You know, I am almost always impressed by the quality of Miller’s Falls tools. I like MF drills and planes, and they’re often much less expensive because they don’t say “Stanley “. Whenever I pick up one of their quality tools, I wonder why they didn’t make it? I guess quality isn’t going to always win in the market place? There’s a lesson there somewhere. Cheers from Waterloo Claudio (very happy to be at home, finally!) |
|||
263906 | Brent Kinsey <brentpmed@c...> | 2017‑11‑13 | Re: Hot mic |
The MF mic feels really solid and well made. The fit and finish are fantastic. I am very pleased with it. As far as a standard to test it against, since this is a 0 - 1" mic it is just set against The anvil Sent from my iPhone Brent Kinsey |
|||
263913 | Kirk Eppler <eppler.kirk@g...> | 2017‑11‑13 | Re: Hot mic |
" On Mon, Nov 13, 2017 at 7:10 AM, Brent Kinsey |
|||
263915 | Erik Levin | 2017‑11‑13 | Re: Hot mic |
Quite a nice tool. I have one MF- in metric- and it is a smooth, easy to red tool. This mic also was made with the Craftsman name on it (just saw one the other day, in fact) and has a very distinct ratchet design. MF also came in several other designs. *** This message was sent from a convenience email service, and the reply address(es) may not match the originating address |
|||
263917 | Ed Minch <ruby1638@a...> | 2017‑11‑13 | Re: Hot mic |
Would it be true that once you are zeroed, then everything HAS to be right because of the threading of the “plunger thingy”? Also, a penny would seem be a bad gauge because they aren't all the same to start with and they wear. Ed Minch |
|||
263920 | John Ruth <johnrruth@h...> | 2017‑11‑13 | Re: Hot mic |
Brent, Some 0-1" micrometers came with a 1" standard in the form of a round disk 1" diameter and about 0.25" think. They had a hole in the center, presumably to help grasp them and also to hang them up. I have an old B&S 0-1" mic with the Vernier scale to read to 0.0001. This has B&S a black cloth-covered clamshell case with spaces for the adjustment wrench and the disk standard. [I don't believe that a simple micrometer like this can actually read down to 0.0001. The last digit is probably more of a "suggestion" than a fact. Just holding the mic in the heat of your fingers might make a difference - and Starrett certainly made mics with hard rubber insulation on the frame.] John Ruth ________________________________ From: OldTools |
|||
263921 | Claudio DeLorenzi <claudio@d...> | 2017‑11‑13 | Re: Hot mic |
Re Micrometers (I love precision tools!) One of my small ones came with a small ball anvil, I guess for precision indicating on round stock? I can’t recall off hand if any of the small mics came with any standard, but these were always estate sales or flea market buys, and people often take out stuff from the cases if they don’t know the purpose of the part. You sometimes see the little wrenches and standards (even gauge blocks) on sales tables, long separated from their micrometer or tool sets and sellers who have no idea what they are. Don’t some of the vernier scale mikes measure in tenths so the resolution is indeed 0.0001 (0.001”/10)? One complete turn on a 40TPI thread is 1/40=25 thou . The main division on the mic thimble is in thou, and the vernier divides each thou by 10, ie does the last tenth on the sleeve (or whatever that part is called, with the longitudinal lines- and yes I realize that we are interpolating a bit on these, and all we are really doing is narrowing the error bars). Even without the vernier, you can guess whether you are half way between the marks (ie plus or minus 5/10ths, ie 0.0005). Either that, or I have been doing it wrong, haha. Maybe a real machinist can chime in here? I don’t use these every day, so I don’t have a high confidence level in my info. Cheers from Waterloo Claudio |
|||
263924 | John Ruth <johnrruth@h...> | 2017‑11‑13 | Re: Hot mic |
Claudio, Yes, my mic with the extra Vernier scale can "resolve" down to 0.0001. However, that doesn't mean I'd trust it down to 0.0001! Starrett's current-production 0.0001 micrometer is specified as: Accuracy (in): +/- 0.00005. That's for the modern T221XL version with carbide anvil faces. Mine has only the hardened-steel faces and an unknown amount of wear. That's why I think the last digit on my example would be "just a suggestion" ! John Ruth ________________________________ From: Claudio DeLorenzi |
|||
263925 | Erik Levin | 2017‑11‑13 | Re: Hot mic |
John wrote:>[I don't believe that a simple micrometer like this can actually read down to >0.0001. The last digit is probably more of a "suggestion" than a fact. Just >holding the mic in the heat of your fingers might make a difference - and >Starrett certainly made mics with hard rubber insulation on the frame.] Actually, they can do better than that, though most handheld mic's have vernier scales that are too small to do better, and, yes, hand heat makes a difference, especially on larger mic's. The best I have in inches is 0.00005" (50 milliionths of an inch, or 1.27 microns) and holds to about 0.0001" over the one inch travel, but when it was new would have been better. It has a large thimble, so it can be easily read to that resolution. I also have a 1 micron metric, but it is only spec'd to 3 microns over 25mm travel. The vernier scale mics are the same as the non-vernier except for the extra lines on the barrel/sleeve, and Mitutoyo claims that you can read to 0.0001" with a 0.001" mic, as the graduations are the appropriate width for this. I don't recall if the lines are equivalent to 0.0001" or 0.0002" wide, but estimating to better than 0.0005" is a bit sketchy, calibration and tracability of the eyeball and all. The 1" round standard is useful to check for detecting common wear issues, in particular near the zero where the most wear happens, as well as providing a check against the zero for confirmation. The main use, IMHO, is for checking calibration when the tool will be used to measure round parts. Yup. It makes a difference. The tool is best calibrated a) at the dimension to be measured, and b) using a standard of the same geometry as will be measured. Not a big deal in general, but for the highest precision work (think a no-play, polished, slip fit for a shaft), it makes the difference between a fine job and merely workmanlike, or even unsatisfactory. I use gauge pins for this most of the time since they are inexpensive and readily available to better than one micron in whatever size you need. No, I don't work to that tolerance very often and it is not my forte, but I like fine tools (gee, go figure) and like to keep them in top trim, and pay for annual re-certification of my most used standards. It actually has paid off. Demo I have done with students: Using a large outside (caliper) micrometer with no heat shields and a good, mirror shine, preferably carbide, anvil -- I use a 6" Tumico tubular frame, as I have one that meets the requirement and shows the effect well due to the low mass -- measure the standard with the mic held in a stand and temperature equilibriated. Then, hold the mic for a minute (by the frame) and remeasure. The 6 to 9 millionths/degree F growth (on a 6"mic, a 10 degree F gain over the 8" of the frame is about 50 millionths of an inch) is easily measurable. Then remount in the stand and let the standard warm in a pocket for a few minutes (from 20 to 35C, or 68F to 95F). Same thing. Then remove the spindle and sight down the bore. You are looking at a reflection of your pupil, and is is easy to see that it is centered. Hold the mic frame by one side and watch your pupil creep toward the other side as the frame bends. On a 1" 0.0001/0.01mm mic, it is really not that significant on a 0.0001" mic, and pretty much insignificant on a 0.001". *** This message was sent from a convenience email service, and the reply address(es) may not match the originating address |
|||
263926 | Michael Filler | 2017‑11‑13 | Re: Hot mic |
I love mics, really all precision measuring stuff. These are easy to collect, small ( a bunch fit in a shoe box), actually do something (moving parts to play with) and are just one more slippery slope to slide down. Anybody need one, let me know, yours for the price of postage. I'm about to join a mic 12 step program, if I can find a local chapter. Yes, the threaded thingy inside is a 40 pitch, so 1 turn is 25 thou. Yes, the only necessary adjustment is to set 0 when the anvils make contact using the ratchet. Don't crank down using the sleeve, this is a light touch tool. Keep the faces clean. While we're on the subject, NEVER, EVER put a mic away with the spindle and anvil in contact. Temperature changes could damage the mic. A wipe with a rag with a very light weight oil is good protection from corrosion. Even hand body temperture affects the frame, the reason for the plastic insulation on some models. Others use a tubular frame. The frame ridges on the classic Starrett 436 are partly as temperature compensation, if the temperature goes up the whole thing expands, but the outside of the frame expands more, pushes the anvil back in. And yes, the lines on the rotating sleeve are classic vernier scale, find the one line on the sleeve that lines up with the non-rotating part, read that line as "tenths". The 1" standards are to set the zero for 1" - 2" mics. Zeroing needs doing from time to time. It is a friction lock of the spindle/screw and the spindle. Think of putting two washers on a bolt. They can still slip. Calibration, checking the accuracy full scale, is an annual thing, and should be a direct result of the thread pitch. If it ain't right not much you can do, toss it, unless it is a backlash issue, or simply not zeroed. There are some ingenious methods to take out almost all backlash. Calipers are a bigger problem to keep true, as the rack and pinion setup is suseptable to particles, broken teeth, crud, and the rack is exposed. We call them guess-o-meters. The ball style anvil can be used on curved surfaces, like the wall thickness of a tube, as long as the radius of the tube is larger than the ball's. (Woundn't be able to get the mic in there if it wasn't) They also make "tube mics", where the anvil part of the frame is a rod of about 1/4". A lot of guys keep a second set of mics around as "loaners", cheap on ebay, and if some gorilla cranks on the sleeve it ain't the end of the world. Sent from Yahoo Mail on Android |
|||
263927 | Claudio DeLorenzi <claudio@d...> | 2017‑11‑13 | Re: Hot mic |
In Engineering school at U of T, we were taught in a lab course that it was best practice to use instruments rated for one decimal place greater than what you needed to be certain of. So if you needed a "good" thou measure, then you should spec a tool that capable of measuring down to tenths, one decimal over. I have no idea if that is still true today, with all the fancy optical and electronic digital wizzbang gizmocity available now. I was just thinking that the DEC computer I used to program in the 1970's (punch cards and Fortran!) took up the whole basement of the building and required special cooling systems, meanwhile today, that little cell phone in your pocket right now is literally thousands of times more powerful. And also, duh, I just realized the Tumico probably stands for Tubular Micrometer Co. Weird, it didn't occur to me before you mentioned 'tubular', haha- ( Somehow, I pictured a shortish Japanese man with a small moustache- a nice Mr. Tumico- who made it to the big time by building very nice micrometers in the USA). Cheers from Waterloo Claudio PS it's after 5, I'm off duty, and I am gonna dip into a private stash of some single malt. (Wish I good push a little bit of it down the intertoobs to share with you all. Who knows, maybe with future versions of 3-D printing, it will be possible some day, meanwhile, I will just pass the electronic spittoon along instead ) |
|||
263928 | Brent A Kinsey <brentpmed@c...> | 2017‑11‑13 | Re: Hot mic |
Thanks again to everyone for all of the information. I had metal shop and wood shop in school, but the metal shop class was really just working with sheet metal and spot welders...the ubiquitous toolbox project. So I have never had any machining training or experience. This is my first mic so I have been reading up on how to use it. I like that it has the ratchet mechanism; that will prevent me from over tightening or trying to guess just how snug is enough when measuring. This particular mic isn't graduated for tenths, just to thousandths and I will really probably never need anything more discerning. I have a small atlas lathe (which COULD be run by treadle) but it is a project I am rebuilding and will likely never do any serious machining. May I ask, who posted the need to divest a couple of mic's? There was no signature on the post and my email only show Old tools as the return address. I need to pick up a good mic for my son in law to replace this one he gave me. He didn't have one either and was planning on keeping this until he saw how enamored I was with it. He graciously gave it to me and now I should find a replacement for him. Thanks again! Brent Sent from my iPad |
|||
263929 | Claudio DeLorenzi <claudio@d...> | 2017‑11‑13 | Re: Hot mic |
We need so many 12 step programs in this group, my friend, so many... Speaking of nice oil, I even splurge on the Starrett Instrument oil (the one in the yellow bottle with red print). Even if I don't use the tool for 10 years, that oil never gets gummy or sticky, and I have never had any rust problems either (very damp in the summer up here). It's good stuff. A small bottle lasts me for years. The Starrett marketing department- every time I see one of those red boxes on a sales table- I know I'm going to pick it up and at least look at it. Cheers from Waterloo Claudio (wondering if I put away any micrometers with spindle-anvil contact) |
|||
263930 | "Ed O'" <edo@e...> | 2017‑11‑14 | Re: Hot mic |
I have heard old machinists kept pennies in their tool chests, supposedly to prevent rust. I have heard it numerous times, and an explanation of how it would work has never been provided. All I can guess is that solid copper might change temperature faster than steel and somehow attract condensation first. I think it was 1982 that pennies ceased to be all copper. Ed O' |
|||
263931 | Matthew Groves <grovesthegrey@g...> | 2017‑11‑14 | Re: Hot mic |
Zinc is often used as sacrificial anodes due to it’s placement in the galvanic charts. Maybe it’s a reference to the new pennies and their zinc-ness? Matthew Groves Springfield, MO |
|||
263932 | Mike Rock <mikerock@m...> | 2017‑11‑14 | Re: Hot mic |
And I've bought more than a few chests with a salt shaker back in the corner.....never used, sat there for a long time by the evidence. I thought it was for spicing up hard boiled eggs but an old machinist told me it gathered moisture and kept his tools from rusting. He was a WWII Naval shipboard machinist. He had the old polished Starrett tools too. Not the glass beaded finish we see today. Those suckers would rust in a heartbeat if not for the camellia oil and the salt shaker.... On 11/13/2017 6:32 PM, Ed O' wrote: > I have heard old machinists kept pennies in their tool chests, supposedly to prevent rust. I have heard it numerous times, and an explanation of how it would work has never been provided. All I can guess is that solid copper might change temperature faster than steel and somehow attract condensation first. I think it was 1982 that pennies ceased to be all copper. > > Ed O' > > >> On Nov 13, 2017, at 11:18 AM, Kirk Eppler |
|||
263934 | Claudio DeLorenzi <claudio@d...> | 2017‑11‑14 | Re: Hot mic |
I don't know about the salt shaker ( salt pulls moisture out of the air only up to a point), but be cautious with your Camelia oils. Natural oils will tend to crosslink over time upon exposure to reactive gases in the atmosphere and get sticky and gum up stuff, and I wouldn't use those natural oils (which are always combinations of various chain lengths and so on) on sensitive measuring tools ( especially tools that you basically have to disassemble to clean, using ultrasonics and special cleaners). Much safer to use instrument oils designed not to turn into varnish. Cheers from Waterloo Claudio |
|||
263939 | Don Schwartz <dks@t...> | 2017‑11‑14 | Re: Hot mic |
On 2017-11-13 7:31 PM, Claudio DeLorenzi wrote: > Natural oils > will tend to crosslink over time upon exposure to reactive gases in the > atmosphere and get sticky and gum up stuff Olive oil f'rinstnce. It NEVER dries. It just gets stickier and stickier! Horrible stuff to remove from - say - a salad bowl set. DAMHIKT! Don -- "You can tell a man that boozes by the company he chooses" The Famous Pig Song, Clarke Van Ness |
|||
263948 | george@g... | 2017‑11‑14 | Re: Hot mic |
Erik Levin described a fine way of demonstrating the "humanity" of a micrometer ... There's a way around that problem: use a toolmakers microscope. One looks at the object in question through a modest-magnification 'scope - usually with a 10X eyepiece and a 3X to 10X objective lens, which (very important !) must be in focus in the plane of the object which you are measuring and twirl the two micrometers (usually with large barrels which facilitate reading to tenths and even quarters of tenths) until one edge and then the other edge is centered in the crosshairs. There's no touching of the frame of the micrometer except at the focus knob and on the outsides of the barrels, so the thermal expansion problem is minimized. And there's no "feel" at issue because there isn't any contact between the micrometers and the workpiece. I once had to do this while seated at a huge round conference table with my client yacking away in a spirited and irrelevant conversation with about half-a-dozen interested parties while I was checking the thread pitches of a number of broken bolts for signs of stretching (indicating an overload). The potential for 0.025 errors terrorized me ... Now I've just retired (at age 80) so it's just a matter of remembering what I was doing a few moments ago ... When I'm machining something for a press fit I usually have to rely on the feel of a small-hole gauge and then, twice over, the feel of the micrometer in order to get the couple-of-mils interference fit that keeps 'em together after applying the arbor press. A few tenths really do matter, and those feels are important - mainly to keep them consistent. Recently I was fixing a broken watchmakers lathe cross slide and had to make another 40 t.p.i. feed screw, which had a short length of 50 t.p.i. threads for the graduated thimble that doubles as the backlash adjuster. The lathe had a long life doing chucking work before I got it, so the lead screw is quite worn. I finessed the wear while making the feed-screw portion of the piece by doing that part with the drill rod supported with a center rest about five or six inches from the headstock where there is presumably less wear, and then doing the adjustment thread up close to the headstock. It was a pleasant surprise that the fit of the little graduated thimble gets progressively tighter, the more thread engagement there is, because of the pitch error in my lead screw - transferred to the 50 t.p.i. thread on the feed screw - which eliminates the need for any setscrew to keep the backlash adjustment in place. It's actually rather too tight, needing two pairs of pliers and suitable leather cushions, to set the adjustment. I made two such feed screws; the first was a lad too loose, and they both exhibited the same tightening effect for the graduated collar. Getting the taper out of the three-inch long feed screw was the hardest part of the whole job, partly with the setover of the tailstock, and partly getting the center rest adjusted. That was much easier than it would have been to graft on a length of rod that would have been needed to reattach the broken-off (and lost) handle. There were also two lost gibs and an entirely missing top slide to make from scratch. All that took a couple of months of "spare" time. Works fine now. George Langford in SE PA |
|||
264115 | Dragon List <dragon01list@g...> | 2017‑11‑30 | Re: (no subject) |
Thanks for that, Gary. Incredible skills, patience, and result. Best, Bill Felton, CA |
|||
Recent | Bios | FAQ |