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Is it good practice to leave a rather heavy height gage on a granive surface plate ?

TNB

Stainless
Joined
Aug 18, 2002
Location
France
I have 18x24 granite surface plate and was lucky enough to find myself a Tesa M 350 height gage for cheap.

The height gage weighs a little more than.70lbs, so I wonder if it's wise to let it rest on the plate or if I should find a convenient way to take off when I don't use it (wich is most of the time)...

I think I have the answer, but I tought I'd ask to the metrology specialists anyway ;)
 
If the plate is in good shape and decent thickness, it won't hurt it to keep the gage on the plate. And it's better for the gage and your back - no risk of "bouncing" the gage on the plate surface when returning it, less likelihood of trapping debris under it when setting it down, etc.
 
I guess what has me wonder is the fact that 18x24 is probably the smallest suitable size for using such an height gage, and the thickness goes with the size.

I wonder what could be the practical effect of leaving a significant weight in one particular area of the plate permanently (more or less).
 
I think it wouldn't have much effect, as granite doesn't exhibit ductile flow under load the way some materials can (like many plastics). Mud's thought on placing the gage over a support point's is helpful if the geometry works out for what you want to do.

If you have a precision level, and want to do a little (imprecise) testing, you can place the level over various points of the plate and then load it and see what deflection readings you get. It's not perfect, as you can't comp out effects of the level itself or changes in the support structure, but it gives you a "global" idea of how the system behaves.
 
Leaving the height gauge parked on the surface plate pretty much forces you to leave the plate uncovered. Which I'm not a fan of. Don't care how good you promised to be, flat surfaces in workshops get stuff parked on them. Always. Hard enough to keep things clear in proper metrology or optics labs where nothing else goes on.

I'd arrange a parking block alongside the plate with its surface at the same height and slide the gauge onto that when not in use. Maybe one of the small, inexpensive import granite plates would do. Put a proper rigid cover over the plate and a custom sock over the gauge so all is clean when its time to use them. Still hafta find somewhere to put all the stuff that got dumped on the cover before you can use it!

Clive
 
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Personally - I am intrigued by a 70# height guage.

I have a 24" Mit (that doesn't work) and it prolly only weighs 25# ???
When I go to replace this thing - maybe I need to consider that someone else has upped the ante?



Got pics?


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Think Snow Eh!
Ox
 
Leaving the height gauge parked on the surface plate pretty much forces you to leave the plate uncovered. Which I'm not a fan of. Don't care how good you promised to be, flat surfaces in workshops get stuff parked on them. Always. Hard enough to keep things clear in proper metrology or optics labs where nothing else goes on.

I'd arrange a parking block alongside the plate with its surface at the same height and slide the gauge onto that when not in use. Maybe one of the small, inexpensive import granite plates would do. Put a proper rigid cover over the plate and a custom sock over the gauge so all is clean when its time to use them. Still hafta find somewhere to put all the stuff that got dumped on the cover before you can use it!

Clive

I guess it depends on where you work. Don't recall ever seeing a cluttered granite surface plate. They also get wiped clean for dust etc. at least once a week.
 
I have a 24" Mit (that doesn't work) and it prolly only weighs 25# ???
Got pics?

79463844db89c3e988c1e11b3f8b1469.thumb.png


From the brochure, 73lbs without the control panel and battery...
Awesome piece of tooling btw. Motorized probe, air cushionned with built in compressor, parallelism and runout checking, perpendicularity checking... Amazing.
I was really impressed when I began to play with it and discovered all what it was capable of.
 
Actually. that looks tough to get into some places - being so wide ...

???


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Think Snow Eh!
Ox
 
79463844db89c3e988c1e11b3f8b1469.thumb.png


From the brochure, 73lbs without the control panel and battery...
Awesome piece of tooling btw. Motorized probe, air cushionned with built in compressor, parallelism and runout checking, perpendicularity checking... Amazing.
I was really impressed when I began to play with it and discovered all what it was capable of.

I'd give it permanent right to being on any surface table. The last thing I'd want to hear if anyone tried lifting it to another spot is "Ooops".

MICRO-HITE range | TESA Technology
 
That looks like a Squaremaster with a DRO attached, and Squaremasters have a big piece of granite inside.

My comments are based on an older model that I have - outwardly less fancy, but I believe the internals are more or less unchanged.

There is a heavy cast iron base with a cylindrical column set into it. The carriage runs up and down the column on 6 little preloaded bearings. On one side the column has a rod fixed to it along it's length that's used by the friction drive and to prevent the carriage rotating on the column, on the other side a recessed magnetic scale. The carriage has a counterweight inside the column.
 
Actually. that looks tough to get into some places - being so wide ...

A very comprehensive set of probes and probes holder is available from Tesa retailers, that will allow you to reach almost any point on whatever part ...

07.60148.jpg


At a price !

Tesa Hite accessories set

The Plus-M 350's heart is a steel or cast iron beam (sort of) on which a carriage rides, guided by tiny roller bearings.
The carriage is held by a strap connected to a counterweight sliding at the back of the beam.
The upper pulley encloses a little motor and a ridiculouisly sensitive clutch.

The measure is launched with an upward or downward movement of the probe via the control pannel or the big button at the base ot the column.
The electronics of the control panel will beep and display the actual height of the probe after it detects 2µs of stillness in the system.
The motor then immediately stops and retracts the probe from the part (of a preset value).

Works almost the same for detecting highest and lowest point in bores or on buttons.
Move the probe up or down... contact with the part: beep... Move the part or the column (air cushionned) and the electronics willl automatically detect the reversal point : beep - display of the value...

Don't know if it's really worth its astronomical price when new, but it's very very cool...
 
Seriously? :eek:

Yes seriously. To give you a better idea of what I mean can you imagine machinists acting like slobs in Germany or Japan?

Another "picture" is annoying brats in supermarkets. Blame the parents.

It's all a question of how you were raised. In machine shops what's regarded as "normal practice" rules. A while back Leigh got upset/annoyed at how someone "stored" their tools (willy nilly on a table in a video) and justifiably so.

Ordnung muss sein is a German proverbial expression which translates as "there must be order." The idea of "order" is generally recognized as a key cliche for describing German culture. Franz von Papen, for instance, cited it in 1932 as Frederick the Great's "classic expression".
 
Yes seriously. To give you a better idea of what I mean can you imagine machinists acting like slobs in Germany or Japan?
[/I]

Germany certainly. Went on tour of the BMW motorcycle factory in Berlin back when the wall was still up. Very underwhelmed. For example significantly unimpressed by the pile of K series cylinder heads sitting on the floor waiting for re-work. The one Bob "loud English works everywhere" Lane picked up should have gone straight in the scrap bin and a tool setter sent straight down the line to check things out immediately after it came off the machines. Tour guide felt it was quite normal quality. Possibly 2 or 3 rejects an hour! Did explain why my K's were, objectively, less than impressive. The hour long Why BMW are Wonderful presentation didn't go down too well, especially after Herr Tour Guide asked if we'd had any issues. Group of 25 (with 3 scientists, 4 engineers, 4 toolmakers and 3 skilled craftsmen) having maybe a million Bimmer miles between us. There is brave and there is stupid!

I've unbuttoned more than a few German, and Japanese, products that were all mouth and no trousers inside.

Long ago learned that the School Science lab everything uber tidy and put away immediately appearance outside of properly organised series production or specialist test factory was evidence of nothing much getting done. A bit of clutter is pretty much inevitable, especially with several jobs on the go at once, but you do have to make an effort to stay ahead of things. My surface plate has nice solid cover with all the height gauges et al properly boxed and stacked or shelved close by. No way is it bench or shelf extension but its fairly common for me to lay out micrometers and other test / measurement gear in their opened boxes on the cover. A 12" micrometer or 24" vernier takes up a fair bit of room. There are times when proper exploitation of an always clean, always clear surface is appropriate.

Clive
 








 
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