So I've been away from the 'zone for a while, busy with a few projects. One of which is an update to the plans. I've released version 2.1, which corrected a number of small errors (all of which are now listed in the errata area of my website) and a few important modifications. The big one is....
THRUST BEARINGS ADDED TO THE Z AXIS LEADSCREW.
A pair of needle bearings have been added to the leadscrew. This accomplishes a couple of things: it absorbs the thrust forces that the motor bearings used to be placed under, and it will prevent any chance of the Z axis dropping to the table if there is a failure of the motor to coupler connection (more on that below).
The new thrust bearings only involve the fabrication of two additional parts. In the 2.1 plan update the thrust bearing addition is included at the end of the plans as an addendum. This was the easiest way to quickly incorporate the change into the plans. The addendum therefore has a separate bill of materials and parts list.
This addition of the thrust bearings is fully compatible with earlier machines, with a few caveats. On those machines it will reduce the Z travel by about 3/8", and it also raises the Z motor by 3/8". If you are running quad stack motors with a shaft that extends out the top of the motor, it may just touch the inside of the 2.0 cover. On my own machine, a thin 1/8" shim between cover and base quickly solved that.
One other small but important modification is the addition of a set screw to the DumpsterCNC motor coupler. I did some testing of how much torque it took to turn the fully tightened coupler on the motor shaft and it was surprisingly little (barely 18 inch-pounds, which is the equivalent of 280 inch-ounce). So I'm now strongly suggesting the addition of a set screw that can be tightened against the flat on the motor shaft as extra insurance against slippage.
One thing that I unfortunately did not get time to include in this update is the tramming modification that I posted here at one point. Find it here:
http://www.cnczone.com/forums/momus_..._tramming.html
This makes it much, much easier to accurately tram the spindle.
As always, anyone who has purchased the plans in the past can get the update for free. Just email me with your current email address, and some kind of information that I can use to verify that you purchased the plans in the past (name, email address that was used, etc.). You can find my email address on my website, if you don't have it. Please don't PM me here as it will quickly overwhelm my box. And please allow me a few days to get a new download link to you, as I might have a long list of people to send them to.
-Bob
THRUST BEARINGS ADDED TO THE Z AXIS LEADSCREW.
A pair of needle bearings have been added to the leadscrew. This accomplishes a couple of things: it absorbs the thrust forces that the motor bearings used to be placed under, and it will prevent any chance of the Z axis dropping to the table if there is a failure of the motor to coupler connection (more on that below).
The new thrust bearings only involve the fabrication of two additional parts. In the 2.1 plan update the thrust bearing addition is included at the end of the plans as an addendum. This was the easiest way to quickly incorporate the change into the plans. The addendum therefore has a separate bill of materials and parts list.
This addition of the thrust bearings is fully compatible with earlier machines, with a few caveats. On those machines it will reduce the Z travel by about 3/8", and it also raises the Z motor by 3/8". If you are running quad stack motors with a shaft that extends out the top of the motor, it may just touch the inside of the 2.0 cover. On my own machine, a thin 1/8" shim between cover and base quickly solved that.
One other small but important modification is the addition of a set screw to the DumpsterCNC motor coupler. I did some testing of how much torque it took to turn the fully tightened coupler on the motor shaft and it was surprisingly little (barely 18 inch-pounds, which is the equivalent of 280 inch-ounce). So I'm now strongly suggesting the addition of a set screw that can be tightened against the flat on the motor shaft as extra insurance against slippage.
One thing that I unfortunately did not get time to include in this update is the tramming modification that I posted here at one point. Find it here:
http://www.cnczone.com/forums/momus_..._tramming.html
This makes it much, much easier to accurately tram the spindle.
As always, anyone who has purchased the plans in the past can get the update for free. Just email me with your current email address, and some kind of information that I can use to verify that you purchased the plans in the past (name, email address that was used, etc.). You can find my email address on my website, if you don't have it. Please don't PM me here as it will quickly overwhelm my box. And please allow me a few days to get a new download link to you, as I might have a long list of people to send them to.
-Bob