Nick_G | 30/03/2015 21:23:59 |
![]() 1808 forum posts 744 photos | Posted by Michael Gilligan on 30/03/2015 21:16:01:
Posted by Neil Wyatt on 30/03/2015 21:04:49:
> There was a program on the TV with Guy Martin fitting fitted bolts on a Spitfire ... Which bolts? . The ones that hold the wings on MichaelG.
Rubbish.! The Spitfire I had used rubber bands and 1/4" wooden dowel to hold it's wings on with.
Nick |
Stuart Bridger | 30/03/2015 22:04:07 |
566 forum posts 31 photos | I already have a DRO on my mill and there the advantage is much more obvious, no more counting handwheel turns and functions like divide by 2 are invaluable. What I am looking for on the lathe is primarily to increase productivity rather than accuracy. I am thinking that it will help on the carriage more than the cross slide. When i did my apprenticeship some 35 years ago we had no DROs then... I am relearning my lathe skills after a 30+year break, productivity is improving (and scrap rates are decreasing), but my thoughts are a DRO will really help. |
jason udall | 30/03/2015 22:14:36 |
2032 forum posts 41 photos | a couple of things.. the guy martin "bolt" was a between center cylindrical ground pin. it may have been that close a fit.
the other thing.. adding a dro will make your life easier. more fun even. it will even help controlling your TOOLPATH. .it depending , on wear elsewhere, will not guarantee your parts dimentions.. that said.. more resolution is always nice..but may just serve to make you more unhappy about the machine its attached to.. I would not look for better than tenth of the hand scales....(if say 5 thou scale then 0.5 thou dro) ..unless un upgrade is in the offing...... Edited By jason udall on 30/03/2015 22:17:58 |
daveb | 30/03/2015 22:35:16 |
631 forum posts 14 photos | Posted by Neil Wyatt on 30/03/2015 21:04:49:
> There was a program on the TV with Guy Martin fitting fitted bolts on a Spitfire which although they had been machined to the correct size Guy holding one meant it did not fit as he had warmed it up. Which bolts? I can't believe they would have turned out many like that in war production!
I remember reading about fitted bolts that held the wings on, they were always a good fit but later marks needed the bolts cooled (LOX?) before they would enter the holes, Vickers were not impressed with the fitters who made the holes bigger. Dave
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Jmccrack | 31/03/2015 01:57:02 |
9 forum posts | I just fitted a 6' igage on my cross slide. I have a grizzly 14" x 40". I am please with the way it works, But as with any DRO you still have to know how to use a mic Here in Canada it cost me $40.00 well worth it if only to use as a reference with the dial on the machine. |
JasonB | 31/03/2015 07:33:50 |
![]() 25215 forum posts 3105 photos 1 articles | Although the Sinos will read out to five places behind the point when set to imperial, they actually jump in 0.00019 or 0.00020 steps so that is where the 0.0002" resolution comes from. In Metric they read in 0.005mm steaps Its worth looking for a readout that combines the carrage and topslide readouts into one line of display as you may find it hard to set that last 2/10ths cut with the carrage handwheel, the topslide being easier to put on a small cut with The |
John Stevenson | 31/03/2015 09:27:40 |
![]() 5068 forum posts 3 photos | Posted by Bogstandard2 on 30/03/2015 23:04:34:
Stuart, I have two Sino display heads (four measuring heads) on my largish lathe (Chester Crusader) and the display heads can be set to read to 5 digits behind decimal point. I tried to use it at that setting and it was almost impossible, a fly farting as it went past would cause the display to jump all over the place. I now only ever use four places on both my lathe and mill, and life is very sweet. John
.
Many years ago when DRO's were mega expensive and very basic one of my customers had machines fitted with Heidenhain DRO's that read to 1/2 a thou. Last digit went 0, 0.5 0, 0.5 etc
When they upgraded to BS 1066 or whatever it was before BS9000 they had to fit all new DRO's to read in tenths 0.0001, 0.0002 etc and I bought a couple of the older two axis ones off them to fit on my round column mill drill, remember paying £400 for a 2 axis second hand setup in those days.
Next time I went into their works ALL the machines had masking tape covering the last digit because the operators were fed up of the dancing numbers. God knows what that operation cost for no outcome. Edited By John Stevenson on 31/03/2015 09:28:39 |
Ken Gillott | 31/03/2015 11:05:04 |
6 forum posts 1 photos | I fitted 4 DROs to my Chester machine centre/lathe about 4 years ago. The milling head and tailstock DROs are read directly no problem, however I had to fit two remote head LCD readouts for the lathe saddle. The main problem I had was reliability of the cables at the DROs, which are non standard rubber 4 contact affairs. In desperation I dismantled one unit and with some difficulty soldered in a miniature USB socket which has been ok so far. I still found the DROs & head readout units themselves to be unreliable - which is hopeless if undertaking co-ordinate drilling. Replacing the DRO LR44 batteries with 100uf capacitors fixed part of the jitter problem. Next one of the head LCD readouts switches fell apart - impossible to find a replacement, so I bit the bullet and decided to design and build my own and used nice bright 0.7 " LEDs (Microprocessor based systems is another hobby). I had always thought the half thou last digit a bit daft so I wrote the software to display in .0001" increments......oh dear, the digits do leap about. I put up with them last year but have changed to half thou to try this year. Hopefully I will now return to producing scrap metal instead of programming bugs!
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Ady1 | 31/03/2015 12:03:30 |
![]() 6137 forum posts 893 photos | I only use direct cheapo DROs but I do have a tip for anyone who has live wire weak point issues because my e-cig charger gets heavily used and the wires will soon fail if they are not properly supported I whipped all the weak points with thread, like a fishing rod whipping, then squirted cheap superglue onto those whippings to strengthen them Instead of a charger lasting for a few weeks my latest one has been going for months |
Stuart Bridger | 31/03/2015 13:03:49 |
566 forum posts 31 photos | Just as a FYI, it is about a 30% premium on the scale price to go from 5um to 1um |
Crocadillopig | 31/03/2015 13:47:36 |
30 forum posts 4 photos | [Just as a FYI, it is about a 30% premium on the scale price to go from 5um to 1um] Stuart, that ain't necessarily so. Check out **LINK** I bought a system from this firm at 1um for my lathe, and one for my miller from M-dro at 5um at virtually the same price! |
Brian Rice 1 | 31/03/2015 15:37:58 |
82 forum posts 11 photos | Would not do with out mine on mini lathe my accuracy as Improved 100 percent no more guessing. |
Neil Lickfold | 01/04/2015 06:15:12 |
1025 forum posts 204 photos | It is not that much more money to have the more accurate scale on the X + Z axis, you can choose if it reads in 2 or 3 decimal places as well, apart from radius or diameter. Digital readouts have lots of conveniences. Some have the ability to set tool numbers and zero them , so interchanging tools is very easy without having to re zero or reset the tools. Neil |
Gordon W | 01/04/2015 12:12:33 |
2011 forum posts | It is worth remembering that setting , say, 1 thou' on the slide does not mean that the machine will cut 1 thou'. |
Neil Wyatt | 01/04/2015 12:39:17 |
![]() 19226 forum posts 749 photos 86 articles | The capacitative scales (regardless of resolution) work to a code that uses 20,480 positions per inch. So you can exactly denote any power-of two fraction from 1/1 down to 1/2048. 1 thou = 20.48 units. 0.1 thou = 2.048units 0.01mm = 8.063 units. 0.005mm = 4.031 units Note these aren't errors and that the rounding required (if done properly) only introduces errors far smaller than the resolution of the units. The code allows for more sensitive scales than currently made, and you can make a stand alone readout that works to 0.0001" but the jitter will make it unusable like in John's example. My homebrew displays round to the nearest 0.0005". If the errors in the output follow a genuinely gaussian random distribution (which can't be guaranteed) you could use oversampling to increase the resolution to spuriously high levels. I don't know if the lower resolution readouts still output every step of the 20480 per inch. Neil I feel a metrinch moment coming on... |
Les Jones 1 | 01/04/2015 14:13:27 |
2292 forum posts 159 photos | Hi Neil, Les. |
JasonB | 01/04/2015 14:23:55 |
![]() 25215 forum posts 3105 photos 1 articles | Posted by Les Jones 1 on 01/04/2015 14:13:27:
Hi Neil, Les. Neil, does this mean the Igaging scales are Metrinch compliant? |
Michael Gilligan | 01/04/2015 14:36:26 |
![]() 23121 forum posts 1360 photos | Posted by Neil Wyatt on 01/04/2015 12:39:17:
I feel a metrinch moment coming on... . Neil, Given the SI definitions of the metre and the second; it's quite likely that the EU will [next April?] ban the use of both decimal and binary, as both systems are incompatible with Cæsium transitions. The Prime Factors of 299,792,458 are:
2 • 7 • 73 • 293339
The Prime Factors of 9,192,631,770 are:
2 • 3 • 3 • 5 • 7 • 7 • 47 • 44351
MichaelG.
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Nick_G | 01/04/2015 14:41:09 |
![]() 1808 forum posts 744 photos | . As you are contemplating tight tolerance scales I am 'presuming' that you are not on a tight budget. If that is in fact the case I would consider spending those extra coins purchasing magnetic scales. 1) They are a doddle to fit. 2) They are already coolant and swarf proof. 3) They are of a smaller profile. This matters quite a bit on a small lathe so that the amount of capacity reduction is minimised. If a normal (even slim) is fitted by the time a protective cover has been fitted a couple of inches movement / capacity may be lost. This may not be an issue on a large lathe but can easily become a problem on smaller machines that are associated with most model engineers. Nick |
Stuart Bridger | 01/04/2015 14:53:48 |
566 forum posts 31 photos | I did look at magnetic, but based on machine DRO's specs, they quote an accuracy of +/ 0.015 mm "typical after installation" even on the 1um resolution, which doesn't compare very favourably with the +/- 0.005mm quoted for optical. The slim optical scale with cover would mean losing about an inch with the tailstock being further way from the chuck. |
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