Quote Originally Posted by tonyfoale View Post
Steve,
You can make perfectly good slits using nothing more than a hacksaw. If you need wide slots you can load two blades in the same saw. i know that hand tools have passed out of fashion but they still have their uses, and often are the quickest way to achieve an objective.
I cheated and used the bandsaw to make the split cuts.


Quote Originally Posted by tonyfoale View Post
The one pictured is/was 1 micron accuracy with 5 micron resolution using the usual X4 quadrature trick. However, it is with some embarrassment that I have to confess to recently zapping that encoder, accidentally applying 12v to it when 5v is desired and 5.5v is the limit. I found it NOS on ebay for $180, it was a bargain as shown when I asked for a repair quote from Heidenhain. Repair would have been £400 and renewal £1000. More googling and I found a new Ono Sokki GS-1830 Linear Gauge Sensor 30mm for $200 which should arrive this week. That has 1 micron resolution and 2 micron accuracy. So good quality examples are out there for good prices if you look and get lucky. There are dozens of cheap Chinese rotary encoders on the market which work pretty well but I have been unsuccessful with finding similar cheap versions of linear encoders, so new from regular suppliers means $1000 and up unless you get lucky on the internet.
I've recently purchased a China digital indicator 0.001mm resolution @12.5mm travel ($36, £29) which remarkable is pretty darn good so far. At least I have not seen any non-monotonic behavior in it's count. It seems to mimic a 2 micron resolution "Peacock" test indicator. I have no idea what method of digitization is contained in this battery operated indicator. It also has a SPC output port, so it could be read by an external computer for recording. It did not come with a deviation card, nor a stated accuracy. I just looked at 50mm travel and Mitutoyo from China (and probably fake) is ~$270. So I can find a solution, within my means.
Darn, I found a similar indicator to the one just purchased, and it states a 10micron accuracy, so 10X it's display resolution. I guess you have to pay for accuracy.


Quote Originally Posted by tonyfoale View Post
I have just turned 73 so I'm a bit old for prostitution any more. Hobby is a bit mild, "life time passion" would be closer. i used to race motorcycles semi-seriously and now I race in classic events and I try to spend all my non-racing time sleeping or building/preparing my bikes.
In the 70s and 80s I had a business in the UK making bike chassis, many of which have won championships around the world. Since the late 80s i moved to live in Spain and since then I have not done any physical construction for others, finding it easier to tell others how to. So I became a madam and turned to writing, doing seminars and developing software etc. You can see more of my history and activities by looking at the following links in addition to a few posts that I have made on this forum, Homemade Tools built by tonyfoale - HomemadeTools.net . Although I seem to have gained the reputation as the chassis guru it has always been engines that have been a stronger interest.
I retired 4 years ago (60 now). But I spent my "prostitution" life designing avionics for Collins Radio (autopilot, flight management, serial data switches, and protecting against lightning and HIRF, as well as preventing the emission of RFI). I started the metal working bug in high school, back when they had metal working shop (all gone since the 80's in US public schools). I'm mostly self taught, but with recent problems, youtube has been unbelievable in showing surface plate 'tricks'.

I came to this site to get pointers on my missing knowledge.