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### Messages - MN300

241
##### General Mach Discussion / Re: Mirror probing
« on: April 01, 2019, 05:59:43 PM »
I am not proposing to physically rotate the rifle. Once you have the measurements down the center line the rest of the measurements would be calculated for different angles. It's just simple trigonometry. It would take a fair amount of custom programming to make G code or a file that could be used to make G code.
A person experienced with CAD could use the initial set of measurements to create a cross section and rotate it into the full profile. The CAD program would do the rest of the work and generate the G code.

242
##### General Mach Discussion / Re: Mirror probing
« on: April 01, 2019, 05:26:25 PM »
The required compensation problem is one of the reasons why I suggested the approach in the earlier post. The measuring could be done in one pass and then expanded by computation to define the rest of the part. A probe with a bar shaped tip with a V edge aligned with the Y axis should work well.

There are other potential problems with the 3 probe method too.
In the measuring phase how do you measure the offset between the 3 probe tips in all 3 dimensions and then adjust and combine the readings into one file?
The plunger of the microswitch doesn't slide in a precision bearing. Will it be pushed to the side when measuring against an angled surface creating an error?

243
##### General Mach Discussion / Re: Mirror probing
« on: April 01, 2019, 04:29:32 PM »
Bluing on the barrel may interfere with electrical contact.

If the part is not symmetrical in the X axis inverting both Z and Y would rotate the part 180 degrees.

If you use a spherical tip you're really measuring points that are the radius of the sphere away from the part. The surface being measured is not flat so you can't just subtract the probe radius, especially at the edges. The probe radius would need to be subtracted from the measured position of the center of the probe at the angle from the measured position to the center of the barrel. This means both Y and Z would be adjusted. Then the tool radius would be subtracted in the same manner to calculate the center of the tool path. If the probe and the tool have the same diameter, that diameter could be subtracted instead of doing the radius twice.

Some additional adjustment might be required if the angle of the tapered section is too steep. A quick calculation says that error from a small taper angle might remove an extra thousandth or two of an inch.

244
##### General Mach Discussion / Re: Mirror probing
« on: April 01, 2019, 09:55:21 AM »
If the barrels are round, not oval shaped, I think there might be an easier method which would use only one probe.
The centerline of the barrel would be trammed in to the X axis of the mill before measuring and used as the zero reference.
A single set of measurements would be taken down the centerline. They would be mirrored and adjusted for the tool diameter to create a tool path.  That path would then be mathematically rotated a few degrees at a time for successive passes.
What I am suggesting is in effect measuring the radius at many points and converting it to a tool path. Rather than writing a custom program to do the conversion the values could be transferred to a CAD program and it would do the heavy lifting.
If you already have a method of converting probing data  to G code the set of readings could be mirrored and the rotated passes added before entering into that program.

245
##### General Mach Discussion / Re: Mirror probing
« on: March 30, 2019, 07:54:03 PM »
I Googled "quarter rib dimensions" and see the side touching the barrel appears to be defined by 2 dimensions.
http://www.scoutrifle.org/index.php?topic=2580.0
Quote
Dimensions are as follows: A = barrel diameter under the center of the front pair of screws
B = barrel diameter at the chamber
It should be a relatively easy job to make a CAD file for this.
Are the dimensions of the top details specific for different brand scopes? Are these published?

246
##### General Mach Discussion / Re: Goofy forum layout
« on: March 28, 2019, 07:09:13 PM »
I tried the task manager again. When I hit pause the download stopped for about 10 seconds. Then there were spikes every 9 or 10 seconds. After a minute or so they stopped. Then the data would start and stop with pause.
If you change the theme you only are on the screen with the video until you hit Login - less than a second if you are quick.
I tried making a bookmark for the login screen so I could skip the home screen but then an error occurs when I try to log in.

247
##### General Mach Discussion / Re: Goofy forum layout
« on: March 28, 2019, 04:43:16 PM »
I brought up the Task manager and see the network activity go to zero when not on a page with the video.

248
##### General Mach Discussion / Re: Goofy forum layout
« on: March 28, 2019, 03:57:10 PM »
I have reverted to the old theme (SMF default - curve) as per Chaoticone's instructions - all is right in the world now. No video, same screens as before.

249
##### General Mach Discussion / Re: Goofy forum layout
« on: March 27, 2019, 07:27:29 PM »
Sorry Overload, I did not intend my comment to apply to you but was explaining why I didn't comment earlier.

250
##### General Mach Discussion / Re: Goofy forum layout
« on: March 27, 2019, 07:01:40 PM »
I too was thinking about commenting on the new format but there is an old adage "If you can't say anything nice don't say anything at all".
If the new format is better in some way I haven't found it yet.