Hey guys,

I'm having a slight problem with some of my feeler gauges. Some of the larger diameter ones (pretty much all of these: .049", .063", .078", .093", and probably the higher ones too) have a pretty fair amount of bevel on the edges. Even the ones that measure exactly the same all the way around in terms of thickness (measured with a caliper) still vary from side to side and front to back in terms of their final measurement numbers. For example, if I'm trying to measure a tenor mouthpiece and I'm using the .078" feeler gauge, if I flip that gauge around and take readings from all 4 possible edges (the front and back of one edge and the front and back of the opposing edge of the gauge), I'll get slightly different readings all the way around. 

As you can probably guess, this has been driving me nuts. I really want to be as accurate as possible for both learning purposes and actual refacing purposes, and what I've doing so far has been to take the measurement from whatever edge of a gauge gives the highest reading, that way if I find out later that it was wrong, I'll still have room to work with to get a particular reading a little higher later on. However, this does not seem like a very accurate way to get a piece playing really well when you're working on it, so I am wondering if getting the edges of the feeler gauge filed/sanded/milled perfectly flat will resolve this issue. (????) I have measured some of these gauges that are causing problems, and they appear to be even all the way across, so I really think it's the varying bevels that are causing the reading problems. 

Does anyone know where someone could get this kind of work done? Like getting something milled/sanded flat? I have no idea, maybe a machine shop but I wouldn't know where to find one of those... Any help will be greatly appreciated! I'd love to get these gauges set up so that they give the same accurate reading on all 4 possible sides, sometimes when I'm not thinking I'll measure a piece and copy down the measurements only to find that I slipped up and didn't use the same side of the gauge that I normally would use and the reading is different than I intended and then I've gotta go back and re-measure and hope that using the highest measuring side of a gauge will yield a positive result... Annoying to say the least! So far, when I get the targets OK on a reface, the pieces will play well, but none of them has been "really good" yet, only "decent". I'm wondering if once the gauges are filed flat and get the same reading all the way around, if I'll find out that I was using the wrong set of data for refacing. I'd be fine with that, in fact I'd like to know if that's what's been happening, but just need some advice. I thought maybe someone else might've had this problem before. Thanks,

Matt

I have pondered this problem.  I just chose one edge to use and measure it in 3 
spots on each feeler.  I average the readings and use the average in my 
spreadsheet.  I also flipped them around to check for taper.  If the taper is 
more than I can live with, I look for a new gage.  I only had significant 
problems when I was using stacked gages years ago for the thicker sizes.  My 
variation in flipping them around is similar to what I get when I drop them in 
using the same side.  0.2 or less on the gage.

I have has some edges that were to rounded to see where the edge is.  I hand 
sanded these on the same flat surface I use for facing work.  I did not make 
them 90 deg edges.  I just did enough until I could see a distinct edge.  


I think any machinist could cut the edge to be 90 degrees and flat.  It would be 
best to find a "friend" to do it as shop time can be expensive.  You would need 
to do something about the sharp 90 deg edge.  I would tell the machinist to 
lightly "break" it with emory paper and that you would round it more if you 
needed to.  If it is too sharp, it may dig into hard rubber and Dukoff Silverite 
materials when taking readings.

I think it is good to be paranoid about accuracy and precision when you start 
using a new set of gages.  Also, check them once a year or so for wear.  I also 
check my micrometer and calipers using gage blocks.  But don't get paralyzed by 
OCD.   


      

Hi Mojo, 

Thanks a lot for your reply and the info, it is much appreciated. Cool, that sounds good to me. Yeah, that's the thing, I'm getting variations of greater than 0.2 on the gauges that have very round edges. As a matter of fact, I am sometimes getting as much as a 1/2 mm difference with certain gauges when you try the different edges, so that's why I was wondering about it. I also understand about making the edges to sharp, I can see where this could easily damage a rubber or silverite piece. I may try sanding the edges on my work surface just like you mentioned to see if that helps. I'll try not to let OCD take over too badly, ha. Thanks again,

Matt



--- In MouthpieceWork@yahoogroups.com, Keith Bradbury <kwbradbury@...> wrote:
>
> I have pondered this problem.  I just chose one edge to use and measure it in 3 
> spots on each feeler.  I average the readings and use the average in my 
> spreadsheet.  I also flipped them around to check for taper.  If the taper is 
> more than I can live with, I look for a new gage.  I only had significant 
> problems when I was using stacked gages years ago for the thicker sizes.  My 
> variation in flipping them around is similar to what I get when I drop them in 
> using the same side.  0.2 or less on the gage.
> 
> I have has some edges that were to rounded to see where the edge is.  I hand 
> sanded these on the same flat surface I use for facing work.  I did not make 
> them 90 deg edges.  I just did enough until I could see a distinct edge.  
> 
> 
> I think any machinist could cut the edge to be 90 degrees and flat.  It would be 
> best to find a "friend" to do it as shop time can be expensive.  You would need 
> to do something about the sharp 90 deg edge.  I would tell the machinist to 
> lightly "break" it with emory paper and that you would round it more if you 
> needed to.  If it is too sharp, it may dig into hard rubber and Dukoff Silverite 
> materials when taking readings.
> 
> I think it is good to be paranoid about accuracy and precision when you start 
> using a new set of gages.  Also, check them once a year or so for wear.  I also 
> check my micrometer and calipers using gage blocks.  But don't get paralyzed by 
> OCD.   
>

> 

> I think it is good to be paranoid about accuracy and precision when you start 
> using a new set of gages.  Also, check them once a year or so for wear.  I also 
> check my micrometer and calipers using gage blocks.  But don't get paralyzed by 
> OCD.   
>
>> From Jimmitch .. Well said Mojo This is still an art a good feel goes a long way.