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Old 12-23-2008, 04:15 PM
Sheldon Dingwall dingwall is offline
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Default How rigid is the Buddy 48?

I'm interested in a 48" buddy. I'm curious how rigid the machine is. What cuts is it capable of taking smoothly? I'm considering both the Alpha and Standard with a 4hp spindle.
  #2  
Old 12-23-2008, 09:02 PM
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Brady Watson bradywatson is offline
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It is more rigid than a full size tool with the machining area being 24X48" - The tool is bit more stout since all of the crossmembers etc are shorter than a full size tool. But...for those lurking/reading, it is NOT as rigid as a full size tool if you use a PowerStick to extend the table larger than the original 24X48" area. If you make cabinets or other 4X8' sheet sized goodies in your business, then a Buddy isn't the right tool for you. You need a full 4X8 machine that is made for day in day out cutting of parts that size, ideally in Alpha configuration since it has an industrial grade control.

For smaller jobs, my BT48 it's a real pleasure to use. I mainly use mine for secondary operations or small parts. It's nice to be able to access the entire table from the front of the tool, unlike my 5X16' Alpha. In terms of Standard vs. Alpha, you have to honk on the tool pretty hard to make it lose steps. The Standards have a lot more torque than the older PRTs, so lost steps (in a 24X48" area no less) are few & far between.

-B
  #3  
Old 12-24-2008, 11:29 AM
Eric Fuller cubicdissection is offline
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I just got mine, and the first thing I did was make a bunch of finger joints on small boxes. Made the jigs out of MDF with the pieces standing up vertically. Ran through 6 at a time and accuracy was phenominal. I've no regrets. BTW this is a PC/standard unit. Accurate to the thousandth no problem. Ran 50 boxes with no file tweaking or re-zeroing and measurements on the last were identical to the first. The tool just works, period.
  #4  
Old 12-24-2008, 12:06 PM
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Neville Stewart dubliner is offline
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Brady - a question on "Lost steps" I noticed that I lost position in a 3D file the other day when the dust foot edge rubbed against a hold down clamp. It surprised me & in light of your statement about "honk on the tool" , I'm wondering are there " sensitivity settings" for a standard? Thats the only incident of "lost steps" btw. settings were probably 3/2 ips
  #5  
Old 12-24-2008, 12:56 PM
Sheldon Dingwall dingwall is offline
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Thanks Brady and Eric. I haven't been keeping up with the info lately. Is there a difference in arc smoothness between the Standard and the Alpha? I seem to remember the Alpha having courser steps.
  #6  
Old 12-24-2008, 04:47 PM
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Brady Watson bradywatson is offline
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Nev,
It all depends on how fast you are going & what you hit...Steppers lose torque as speed increases & it is not unreasonable for a tool to lose steps after an unexpected collision. FYI - most of us from the early PRT days prefer to leave dust collection off on the newer tools when doing 3D. I leave it on to rough out & take it off when doing the 3D finishing pass. Most of the time, there really isn't enough material coming off of the bit to justify using dust collection anyway...Plus, the savings in wear & tear on your DC is a good idea.

Sheldon,
In most cases you will not notice any difference in arc smoothness between a PRS Standard and an PRS Alpha. Early PRT Alpha and pre-4G Standard tools occassionally had issues with arc 'chatter' on certain materials. Many of the issues with so called chatter stem from poor maintenance (read: dry & worn pinions). ShopBot has resolved/relieved many of these issues by some software and hardware enhancements. The Standards are now microstepping (2000 steps/rev) compared to a PRT 1G-3G 1/4 stepping drivers (state of the art at the time) at 800 steps/rev. PRS Alpha tools use 7.2:1 gearbox motors with at least 2X the torque and resolution, while maintaining a high top speed. PRT Alphas used 1:1 motors and didn't have quite as much torque or resolution of the newer PRS tools. The PRT Alphas also used 20T pinions, which had a tendency to wear very quickly and introduced some cogging (which attributes to chatter), as the pinion began to wear. PRS Alphas use 30T pinions which engages more teeth in the rack than a 20T and has much less wear...and increased smoothness. Sorry so long winded...I figured I'd give you the complete answer.

-B
 

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