Chuck Keysor
04-07-2011, 04:11 PM
Hello. I am slowly reassembling a PRT Alpha 144 x 60. I have some questions, that require some set-up, so please bear with me. Thanks.
From old posts, I understand, that some people with PRT Alphas have had problems with the aluminum struts of the X gantry deflecting. I didn't find any detailed information on this, but while I am reassembling my unit, I would like to head off this problem, IF I have it. But of course I also don't want to fix a problem that I may not have.
The fix that I had read about involved placing one threaded rod down the center of each strut, and then putting those under tension. This then serves to stiffen the strut and eliminate the deflection, as I understood the post.
I have attached a photo of my machine so that hopefully the type of PRT alpha I have can be recognized by the experts who read this forum. My unit was manufactured in the fall of 2004.
I used a digital hieght gauge and recorded the distance from the table top to the center of the bottom edge of the long aluminum strut, with the spindle pushed off to the edge as far as possible. Then I rolled the spindle as close as possible to the center of the x gantry, without hitting my height gage, and recorded the change in height to the table top. Then I repeated this for the second strut. On one strut, the deflection was only .003 inches, and on the other it was .007 and these seemed like good readings.
Question 1: Did I correctly understand the problem with PRT Alphas described in the old posts? Since my readings seemed so good, I am concerned that I might have misunderstood the problem, and thusly did not correctly test for the posted problem.
Question 2: If I did correctly understand the problem, and measure correctly, can someone verify that my small measured deflections are in fact OK? And if so, are there any other things that I should consider to improve my x gantry as I reassemble my unit?
Question 3: If I did not correctly understand the problem, I have attached a detailed image of where the strut attaches to the motor car. There are some labels there and notes to hopefully aid in any replies that may be generated.
Thank you, Chuck
From old posts, I understand, that some people with PRT Alphas have had problems with the aluminum struts of the X gantry deflecting. I didn't find any detailed information on this, but while I am reassembling my unit, I would like to head off this problem, IF I have it. But of course I also don't want to fix a problem that I may not have.
The fix that I had read about involved placing one threaded rod down the center of each strut, and then putting those under tension. This then serves to stiffen the strut and eliminate the deflection, as I understood the post.
I have attached a photo of my machine so that hopefully the type of PRT alpha I have can be recognized by the experts who read this forum. My unit was manufactured in the fall of 2004.
I used a digital hieght gauge and recorded the distance from the table top to the center of the bottom edge of the long aluminum strut, with the spindle pushed off to the edge as far as possible. Then I rolled the spindle as close as possible to the center of the x gantry, without hitting my height gage, and recorded the change in height to the table top. Then I repeated this for the second strut. On one strut, the deflection was only .003 inches, and on the other it was .007 and these seemed like good readings.
Question 1: Did I correctly understand the problem with PRT Alphas described in the old posts? Since my readings seemed so good, I am concerned that I might have misunderstood the problem, and thusly did not correctly test for the posted problem.
Question 2: If I did correctly understand the problem, and measure correctly, can someone verify that my small measured deflections are in fact OK? And if so, are there any other things that I should consider to improve my x gantry as I reassemble my unit?
Question 3: If I did not correctly understand the problem, I have attached a detailed image of where the strut attaches to the motor car. There are some labels there and notes to hopefully aid in any replies that may be generated.
Thank you, Chuck