Test Indicator Question...
- Thread starter DSM
- Start date
JerrySharrett
Senile Member
If you get an indicator with the 1.5" dial in 0.0005" you can read close enough for barrel work. Get one that reads in the + and - without having to switch the lever.
The Interpid brand is expensive but is the best. www.longislandindicator.com
The problem with most 0.0001" indicators is they have only about 1/64 travel where most 0.0005 indicators have about 0.100 or more. If you have only about 1/64 travel the barrel has to be aligned pretty close to start using that indicator.
Jerry is right. If you intend to use the indicator to indicate the bore directly on the lands and grooves, a "tenth" indicator will be difficult to use due to the large (in tenths) steps from the lands to the grooves, plus there are few "Tenth" DTIs with a stem much longer than .5". If you indicate on a rod (such as with the Gordy Gritters method) this will not be an issue, but a quality .0005 resolution indicator will still be the easiest to use. Interapid if at all possible.
Scott
Scott
Picked this up near by from a Craigslist ad for $35.00. Pretty hard to pass up at this price. I looked online for a replacement, they are listed around $260! http://www.amazon.com/Brown-Sharpe-599-7033-3-Indicator-Graduation/dp/B0006J4X7Q
It seems like very nice quality and graduated in .00005". What application would I be able to use something this accurate for?
Good buy?
On a side note, I do have one Interapid gauge coming...need to save for another!
It seems like very nice quality and graduated in .00005". What application would I be able to use something this accurate for?
Good buy?
On a side note, I do have one Interapid gauge coming...need to save for another!
YES! These are high quality indicators and have low stylus spring tension, which means they follow the surface being indicated more accurately than other indicators. They are somewhat fragile, so handle with care. If you order a 1.5' stem (from MSC or others) you can use it to indicate inside a bore or chamber etc. and the resolution will be reduced by one third while the travel will be tripled.
New ones can be had for somewhat less than suggested retail, but still around $245. It looks like you have a set, which costs more. The bar and adapter and be used to mount the indicator on a height gage or other precision instrument.
We use these a lot on NC machining centers and Jig Bores to establish precise hole and feature locations and to pick up surface points to use the machine to take dimensional measurements.
Scott
Last edited:
Scott, thats very helpful, thanks.
Nest question if you don't mind...
I looked on MSC and they only have 1-7/16" stems listed, but there are several different ball sizes and material. What size ball and material should I get? Looks like I have a choice of .0400, .0800, .1200 in steel and carbide. I also saw one on another site with a ruby tip? What would a ruby tip be used for?
Nest question if you don't mind...
I looked on MSC and they only have 1-7/16" stems listed, but there are several different ball sizes and material. What size ball and material should I get? Looks like I have a choice of .0400, .0800, .1200 in steel and carbide. I also saw one on another site with a ruby tip? What would a ruby tip be used for?
I'm guessing that the 1 7/16" stem actually ends up with 1.5" from the pivot point plus or minus. The .080 ball is what I use to indicate on lands and grooves. The carbide balls last longer in applications with materials that tend to be abrasive or simply indicating long surfaces on big machines, or indicating cylindrical parts with the spindle running, etc. Not really necessary for barrel work, but perfectly serviceable. The ruby balls are used for metrology applications because the ruby is less subject to change size with temperature changes.
Scott