The Shop > Tools
Anybody build Dan Gelbart angled laser centre finder?
Manxmodder:
--- Quote from: vtsteam on March 22, 2015, 05:23:21 PM ---You'd kinda have to tram pretty darn good and have real nice bearings for that projection method to work out to 5 microns, as claimed. With projection any error is multiplied by distance, and bearngs don't always wear round, nor are shafts round enough generally on a commercial machine to allow a true circular 5 micron projection tolerance. And machine vibration? Well, I dunno, maybe I'm wrong on this. What do I know -- I live in a lot cruder world! :)
--- End quote ---
Agree,now hand me the centre punch :lol:.....OZ.
PekkaNF:
Thank you all
I am aware that this concept looks very simple, but I'm pretty sure there are few snakes on this paradise too.
* usefullness must be very dependent on laser, you may want to very narrow beam. DG says focusable laser.
* I figured the bearing issue and balancing too, my main concern is actually degree of it.
* VT brought up the tramming issue.....This I didn't give attention it deserve. Although to some extent this laser angular adjustment should come handy in there.
Original paper has a mirror to deflect the beam, I was thinking of tilting the whole laser pointer. Mike &al. have done it before. I'm not getting here any points on originality.
Is there any magic on mirrors for lasers?
I'm going to read those links and think it over. I mounted ordinary laser pointer on my mill and it was very crude in near vertical and at small angle. Focus and linear distances in X/Y plane dictate whole lot. Also the piece and features of it.
VT pointed out interaction on centering and tramming....I have a knee mill and universal (in two planes) head and no drilling quill. I'm trying to found out easy method on centering and tramming (rather on one go.....).
Accuracy is not entirely futile exercise. I'm getting close finding out on my hobby when something is close enough and sometimes not even near close enough. I had some same feelings that John (MBE) about the 50 micron accuracy and stuff, but we all use units and accuracies/certaintity in pretty liberal context in out verbal communication.
Pekka
John Stevenson:
To be honest I think we all have a tendency to go overboard when we can.
I do a 'lot' of bore for bearing fits which have to be good [ note, not quoting figures ]. Over the years I have bought all different types of gauges from my original 'el cheapo ' telescopic gauges to make the job easier / better / more accurate / faster [ delete as required ]
I have bore gauges with clocks , 3 point internal micrometers, internal micrometers of about three different types.
They all sit on a shelf largely unused and I still use my 'el cheapo' telescopic gauges on a day to day basis. :thumbup:
Also in the list of "must haves but never used" ®™ are co-ax indicators [ too long to get in most places ]
Centring microscopes [ too fiddly to use after the first hour has been wasted.
And anything prefixed by *new* because engineering has been around for 200 years and nothing except electronics and materials is new. The Victorians cracked all this years ago.
DavidA:
Pekka,
Re Mirrors.
The astronomy people use 'optical flats' when making reflector telescopes. These are little mirrors that have the silvered side towards the user, as opposed to on the back and covered by a protective layer. This ensures that there is no parallax error as the beam doesn't have to pass through the thickness of the glass.
I suggest a quick look on some telescope or optical site.
Dave.
PekkaNF:
John,
I share that sentiment too...I was about to buy one of those co-axial indicator but found it way too long.
Some of the tolerances and perpeticualrities and other words that borderline between obscurity and offensive are pretty damn hard to meet in many general production environment and bloody close to impossible to measure in any certainty at home work shop.
Last weekend I made (as I need a bushing between boring head and boring bar, it came "good eneough" becaue I did it without any unreasonable pursuit to perfection. Chucked scrabnium (TM) bar on lathe, took skin off, drilled 40 mm deep 6,5 mm, 14 mm and boored it close to 16mm. Then I sufaced it close to 22 mm OD (russian boring head). Tee time. Then I figured that it is way too tight inside, but light go with 16mm reamer did it and outside looked good. Took the bar on milling machine and if I had DRO I may have centered it on both axis, but because flat and cutout really does not matter here, as long as they are in about 90 decree shift I played it with an eye. Then I parted off the bush and deburred it. It did fit pretty good just by feel.
Before I used to measure everything and neurotically and tried to get all on the same temperature and to cut last one to 0,01 mm or better - and often end up being 5,00 mm off :lol:
But sometimes it is refreshing to build something new. Just to see what is there to learn.
Pekka
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version