sonic/laser measure

Not sure it would work well Bob.

The ultrasonic devices I just looked up after reading your message quote

The laser ones seem to have a 1.5mm accuracy, bit of a large tol considering I routinely cut to a 0.1mm accuracy repeatable on my cutoff saw.

Wayne....

Many thanks, another great idea bites the dust then !!! Seems I'll need to get a bigger magnifying glass !!! Bob

distance

purpose of

Bob,

If you are cutting to a stop on a chop saw then presumably the blanks are not too long, could you use a conventional dro scale, with your stop fixed to the sliding head? One company (was it Mitutoyo?) brought out a magnetic strip that could be cut to length and self stuck to a machine bed, with a reader head that passed over it. Alternatively, those cheap dro heads from BW Electronics that have a reel of fine stainless wire that follows the movement of your stop:

How about one of these cheap digital vernier gauges? Suitable mounted this will give very accurate readouts and they are cheap, I've seen them under a tenner.

The limit with sonic or laser gauges is the wavelength.

MH

The pull out wire unit only has a max read length of 500mm. However how about using this together with a main bar that can only be locked at 500mm increments. The readout fixed to the bar and linked to the actual stop which slides along the end 500-600mm length of the bar. This would give you what you need at low cost with a fast setup.

mmmmm......not so sure about the low cost bit. A sensor and a display unit is best part of £250 if I read it right. On the other hand, I have had two of these units for several years, a set on a mill and a set on a Myford...and have had no problems. --

Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

Alternatively,

locked

easier way!"

The "391" will measure 48" and costs £166, no need for separate display as it's built in. I fitted a three axis system to my Bridgeport many years ago as it was all I could afford at the time. However I was so impressed with the facility of having a dro was persuaded to buy 'proper' ones (Newall spherosyn) for the lathe and grinders when later I could afford them. Never seen fit to replace the ones on the Brigeport as they are quite adequate for my usage.

AWEM

On Thu, 3 Apr 2008 17:50:49 +0100, "Andrew Mawson" wrote: "

Roger that..I didn't scroll far enough down the BW Electronics' page. --

Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

Actually thinking about it. Use the smaller of the pull out wire type units. Fix the wire to the product stop plate, fix the readout to something that slides along the stop bar. Machine holes at 500mm increments along the bar. Loose pin the Head unit to the bar as appropriate to the length to be measured. £141 plus a bit of time.

Actually thinking about it, fix the head to the stop plate and loose pin the wire end to the bar. That way the readout is infront of you as you adjust the stop plate.

One post and already two revisions!

As well as the other responses, consider this: the sonic or laser will reflect off the blade itself. The carbide tips that do the cutting are slightly wider than this.

You may also need to take into account the total thickness of the blade depending on if you are cutting a short bit off a long bit or a long bit off a short bit.

While it might not immediately spring to mind, if you have a computer in your workshop. then a simple camera focused on the ruler might do the trick.

You could then make the image as large as the resolution will allow.

Once you have done that, then there are other uses too. Mount it on an arbor and you can centre up the chuck of lathe or mill. Insert software graticles and find the centre of holes and rotary tables, line up workpieces and even use it as a quick clocking device.

(one of these days I must try it, but I am still confused by the technical complexity of a hammer.)

Renishaw used to do a steel tape equivalent fo a glass scale, but it would't be 'cheap'. They were a few hundred £ as I recall and that was

You could perhaps arrange some fixed stops at known points and butcher one or more el cheapo Aldi/Lidl digital verniers.

Richard

I believe Bob is talking about a MEC style cold cutoff saw. They use HSS blades normally 2mm thick.

Wayne....

They also do one with 1200mm at little extra cost

Henry

Yes, your right, it is a MEC saw. I measure from the right of the blade, so blade thickness not a problem, and it is HSS. Some very interesting replies here worthy of me doing some research. I like the look of the extending wire idea. My saw has to the right of the blade a 2 metre long material support table, with an upright length that the stop block slides along, so the other suggestion of a stick on type of glass scale that a DRO head could pick up on is also worth exploring. I have a German made 2 metre rule in use for setting the stop block. This with the magnifying glass is ok, but if you look slightly to one side of the stop block, its easy to go undersize when measuring steel lengths that final size with half a mill in the total. This then wastes that length, and has to be used on the next order that is shorter. Lengths up to one metre are set with my 1 metre vernier, and the magnifying glass !!!! Bob

Hello Bob if you have a two metre rule I have a couple of the old Heidenhein optic readers in metric setup, don't know whether they would read your rule but if fixed to the sliding stop to read along the rule might be a cheap and easy result. Cheers Colin