what vice is that? I would love to have one of those.
From earlier in this thread:
http://cnc-plus.de/en/Workholding/Vises/Mini-Self-Centering-Vise--Machine-Tool-Vise-3414.html
apparently cncplus doesnât ship to the US anymore so i cant get this clamp. Itâs a bummer, was looking forward to getting it and havenât found one like it in the US.
Follow the link, under shipping & payment conditions zone 7 it states united states, so there should not be a problem.
it does say United states in the zone 7 locations, but Mainland US is not selectable for shipping location. when you go through the payment process for paypal, before you complete, it tells you that it cant be shipped to the location(and its not my shipping address since I have stuff shipped to the same address all the time).
go onâŚ
Not at all! I really didnât think it through. especially since the more I think about it I donât even need/want the self-centering. Now my brain is coming up with ways to clamp a piece to my 0,0 by making one wall the bump stop. Stopping at the big box store on the way home to get some threaded rod nuts and dowels.
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Hey @PhilJohnson now that I am done being a smart A**. a ratchet wrench would work great on that. you know those cheap little wrenches with the flip to reverse.
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Here comes another 3D printer to Philâs for sure now. 
That is one slick design.
Want, want, want.
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Let me know when you have these available. In fact put me on the waiting list right now.
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Ah just realized you have two different disigns up there. I def want at least 4 of the ones that work with our wasteboard.
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No problem, Iâve done the some to others before. Oh, well⌠forum karma 
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Welcome to Season 3.
The 269ozin steppers from Stepperonline have a rather high inductance. Powered by 24V they were stalling around 500RPM. This could be adequate for a low resolution / high pitch system, but could pose a limiting factor for a high resolution / low pitch one.
For reference, the X-Carve spins at 40mm/rev, the B-Carve at 5mm/rev. One is faster, the other one more precise. When choosing transmission and gearing sooner or later the trade-off between resolution and speed will surface.
The bottom line is that the previous electronics were holding the machine back. However, since MRR = Feed x DoC x WoC the extra rigidity would allow to compensate for low(er) speeds with high(er) DoCs and/or WoCs which would eventually result in much higher MRR. Speed was not the problem per se.
The problem was acceleration. In smaller size machines and when direction changes frequently, acceleration is more important than speed. If acceleration is inadequate, there can be parts in the gcode when the actual speed does not reach the programmed speed. Adaptive toolpaths are sensitive to this. In some cases, they rely on this (think of narrow trochoidal slotting with multiple changes of direction per second).
I had to settle at 150mm/s^2. Keep this number, this is what weâll be improving.
- First thought was to go with 48V and external drives.
- Second thought was to go with 48V, external drives and lower inductance steppers from Automation Technologies.
- Third thought was to go with 50V closed loop Leadshines (aka âeasy servosâ).
- Fourth thought (and realization) was that real servos are not that more expensive.
Since (a) the machine has already paid for itself and (b) life is short, I opted for the fourth option.
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~1k for 3 servos w/ integrated drivers and a 75V power supply.
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Clearpath?
@HaldorLonningdal, yes.
Even though the goal in this phase is the electronics, the majority of the change happens on the mechanics; on the geometry to be specific.
Thereâs one major change:
(1) switch from dual to single Y transmission
And since this would call for a disassembly/reassembly, itâs a good opportunity to add two minor ones that have been on the todo list for a while:
(2) replace the gantry extrusions with a single piece
(3) extend the Z axis by 50mm in order to add another pair of rail blocks
Thereâs two reasons for doing (1). More powerful electronics in a dual-Y setup emphasize the importance of sync between them (or the possibility/extent of damage in case of lost sync). There are ways to catch an alarm signal in case something happens to either motor in a dual setup, but it gets complicated. The other reason is that the servos come with a fantastic autotune software feature which best works with one motor per axis. Since the single transmission will be placed in the center between the two Y rails, itâs very important to increase Y axis rigidity to eliminate any possibility of racking when cutting close to either edge.
Using a single X extrusion, (2), is a simplification which apart from making the design cleaner, will also help with squaring, ballscrew aligning and will reduce installation steps. This was a âduh, why didnât I think of this in the beginningâ moment. I had automatically placed the ballscrew in the middle, which makes sense on the Z, but is not so critical on the X.
Last, (3), the Makita is rock solid in the current Z, but it would be nice to have an upgrade path to a heavier spindle. Thus, second pair of Z blocks.
Hereâs an abstraction of the before/after for the Y. Rails in green, transmission in red.
