Hi folks. i am looking at the chinese 4th axis attachment on ebay. ha sanyone any experience of these . I was wondering would one of the 100mm models be capable of machining a cabriole leg of 70mm square and about 800mm long. EG 23/4 square and 30inches long.
Thanks for your help
Alan
rotary 4th axis attachment.
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Re: rotary 4th axis attachment.
wood....
a quick search on eBay returned hundreds of results. Yes there were a number that will be up to the task. There are a lot more questions to get answers for before I would buy one tho...
a quick search on eBay returned hundreds of results. Yes there were a number that will be up to the task. There are a lot more questions to get answers for before I would buy one tho...
Gary Campbell
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Re: rotary 4th axis attachment.
I am very interested in adding a rotary as well.
I see some that say 1:6 Ratio's and ones that says 1:20 Ratios.
Two I am interested are:
http://www.ebay.com/itm/CNC-F-Style-A-A ... Swl8NVXF4S
http://www.ebay.com/itm/CNC-Router-tabl ... SwBLlVOmc4
I have a Geko 540 with one Axis open and I sue Mach3
I see some that say 1:6 Ratio's and ones that says 1:20 Ratios.
Two I am interested are:
http://www.ebay.com/itm/CNC-F-Style-A-A ... Swl8NVXF4S
http://www.ebay.com/itm/CNC-Router-tabl ... SwBLlVOmc4
I have a Geko 540 with one Axis open and I sue Mach3
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Re: rotary 4th axis attachment.
The reduction should be determined by your max blank diameter and what resolution you require. For example, 6:1 yields .002" step resolution (1/8 microstepping) on a 6" diameter blank. More than ample for rotary wrapped machining up to that diameter. That said, if you are planning on indexed machining, especially off axial center, then the 20:1 may be a better choice. The 20:1 will reduce max rapid speed to around 50-60 rpm, if that is a factor and you may not be able to position it by hand. Are there backlash specs for that 20:1 reduction?
Gary Campbell
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Re: rotary 4th axis attachment.
I see no backlash specs for the 20:1. Most of what I would be working with should be 2".
Re: rotary 4th axis attachment.
What about planetary gears heads? I found a deal on a 4th axis that uses a Thomson Xtrue 100:1 gearhead.
It says that it has a backlash of 13 arc-mins
It comes with a 160oz Nema 23 stepper.
http://www.thomsonlinear.com/website/co ... /xtrue.php
It says that it has a backlash of 13 arc-mins
It comes with a 160oz Nema 23 stepper.
http://www.thomsonlinear.com/website/co ... /xtrue.php
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Re: rotary 4th axis attachment.
13 arc minutes is 13/60ths of a degree. This is .00378" backlash at 2" diameter. Unacceptable for may use, YMMV. 100:1 is so much reduction that you may never be able to turn the 4th axis at an acceptable rate.
Gary Campbell
GCnC Control
ATC & Servo Controller Controller Upgrades
GCnC411 (at) gmail.com
GCnC Control
ATC & Servo Controller Controller Upgrades
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Re: rotary 4th axis attachment.
Im just having a hard time finding a 4th axis to buy to add to my system.
Right now I am looking at three setups:
http://www.ebay.com/itm/261858842965?var=560705631941
http://www.ebay.com/itm/CNC-4th-Axis-Ro ... SwwpdW5mbj
http://www.ebay.com/itm/CNC-Router-Rota ... SwofxUim8K
I'm leaning towards the 50:1 Harmonic Drive.
I will be using 2-3 inch stock and am looking for fine details. I like to make beer tap handles.
Any thoughts?
Right now I am looking at three setups:
http://www.ebay.com/itm/261858842965?var=560705631941
http://www.ebay.com/itm/CNC-4th-Axis-Ro ... SwwpdW5mbj
http://www.ebay.com/itm/CNC-Router-Rota ... SwofxUim8K
I'm leaning towards the 50:1 Harmonic Drive.
I will be using 2-3 inch stock and am looking for fine details. I like to make beer tap handles.
Any thoughts?
- IslaWW
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Re: rotary 4th axis attachment.
If you do go with the 50:1 reduction remember that you must have a controller capable of data output at your required turning speed. A 200 step per revolution (1.8*) will require 10,000 steps per second at 1 revolution per second (60 rpm) which is not fast. You may have to lower rapid expectations to avoid data choke to the 4th axis.
Gary Campbell
GCnC Control
ATC & Servo Controller Controller Upgrades
GCnC411 (at) gmail.com
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Re: rotary 4th axis attachment.
Hi Folks, Thank you for the replies this gives me a help to better understand whats out there.
Thanks alan
Thanks alan