Don't some people use car boot lid struts for that job?  Thats as a gas spring, not a DRO.   Ian S C

Edited By Ian S C on 16/12/2012 10:27:11

One thing I did notice about the mounting of DRO's in the link is why an angle bracet wasn't used on the Z axis so that the DRO faced the operator rather than being flat against the side of the head and thus out of sght.

The X axis would probably benefit from an angled mounting and the Y axis would probably need a remote read out.

Commercial gas springs are warranted for 2000 cycles. They may last longer, but that is what the manufacturers warrant them for. The main factor is dirt contamination (even tiny amounts of house dust) on the rod which degrades the rod seal.

To put it in perspective, if you cycled the gas spring once per evening 5 evenings a week in a home shop, it would last about 7 years. If you cycled it once an hour for 40 hr / week in a factory setting, it would last about a year.

They work great for a while, just don't weld them on – make them easily removeable so if you have to change them, you can.

A major manufacturer is Hahn, link below.

http://www.hahn-gasfedern.de/en/products/gas-springs.html

Another manufacturer is Suspa, link below.

http://www.suspa.com/us/products/gas-springs/functionality/

Just my $0.02 – your mileage may vary.

JD

Bob,

I've fitted a more-or-less identical set of DROs and a remote read-out to my mill (an Amadeal XJ-12) – the kit having been supplied by ARC. I chose not to have any splash guards, as I don't use flood cutting/cooling fluid. I clean up scrupulously after each session (believe that and you'll believe anything!) and haven't had any problems, yet. They are at the cheap end of the market, but seem to perform well and maintain positions adequately. They certainly out-perform me and my machining abilities. If it's not too cold tomorrow, I'll take a few pictures and post them in my album for you to see the way I've mounted them.

Only one thing I found – the X-axis scale had to be fitted "up-side down" as it were, so that the mini usb plug doesn't get clouted by the Y-axis table when traversing. I found out the hard way and had to buy another scale! Ouch!! Not a very elegant solution, but with the remote read-out display, it doesn't really matter. Oh, and I removed the built-in batteries and powered it all from the supplied mains power unit. Works a treat and no more run-down batteries 'cos I forgot to turn the DROs off!

John

Hi All

Re Counterbalancing the head of anything?

A piece of plastic drain pipe maybe 100mm fitted under the bench to contain weights (made from a couple of cast iron window weights or other scrap you have lying around).

Some stainless steel cable tied to the head and weights.

Some self made pulleys to direct the force……..

No Vat, little cost, and almost unlimited life. (Oh and constant force unlike gas springs that are temperature sensitive and degrade over time.

Cheers

John

Have these 'DRO's improved recently ? I tried using the cheap scales and readouts about 5 years ago and had endless trouble with them, such as :-

Connectors from readout difficult to fit to scales and insecure.

Scales sometimes 'froze' and wouldn't start working again until the battery was removed and replaced

Update rate on the scales was very slow, it was neccessary to crank the wheels on the machine in a tortoise like fashion to avoid overshooting.

The 'off' button on the scales was really a 'standby' button and the battery was still being drained.

General 'glitching' from display and from scales – blank readouts, refusal to zero.

I should point out  I didn't buy the scales or displays from ARC
I gave them away to a friend eventually saying ' here, see if you can make these work, I give up '

Edited By Siddley on 20/12/2012 13:52:16

I do wonder if many of the problems I had with the scales were related to the poor fit of that connector. It wasn't anything like the ARC version, but was similar to a telephone jack, except with 4 wires and smaller. I had to trim the crudely shaped connector to get it to fit and then seal it in place with silicon ( after providing strain relief )

If ARC have solved the issues with cheap scales then it's got to be a good thing.

Sorry for not replying to your message, life has been crazy here over the last week – preparing for my wife to visit her family in the UK, one of our cats broke his leg somehow, had to rebuild the flue for the log burning stove ( again ) – I simply forgot

Feliz Navidad

Siddeley: Connectors from readout difficult to fit to scales and insecure.
There are a type of scales in the same range of values not suffering from this problem because the display is remote and the cable has only one connetor to connect to the display. I think they are called iGaging. See please ***LINK*** .
You can see here ***LINK*** the cable coming out beneath of the "cursor" box so the oil doesn't flow in by gravity.

The old-style connectors were useless. I just soldered teh wires in place and filled the hole with hot melt

Siddeley: Scales sometimes 'froze' and wouldn't start working again until the battery was removed and replaced
Never happened to me with these scales.

I find that when remote powered they are very sensitive to glitches on the power lines especially on power up. I keep meaning to fit 10uf capacitors in the battery compartments.

Siddeley: Update rate on the scales was very slow, it was neccessary to crank the wheels on the machine in a tortoise like fashion to avoid overshooting.
Never happened to me with these scales.

There is a 'fast' option that can only be activated remotely on most scales. This updates about 10-20 times a second – I find it easier to use normal speed and go gently!

Siddeley: The 'off' button on the scales was really a 'standby' button and the battery was still being drained.
Not verified. So, no opinion.

This is so the scales do not 'forget' their setting when switched off. Think of it as a blessing! Cells should last a year or more unless thetemperature gets close to zero (when the discharge rate soars).

Siddeley: General 'glitching' from display and from scales – blank readouts, refusal to zero.
Never happened to me with these scales.

Probably transients on the cables again – make sure they are routed away from motor/control box/switches/fluorescent lights.

Neil

There isn't a seperate quill feed on these machines Sid, just a coarse and a fine operating on the Z axis rack.

In practice it doesn't seem to be a problem.