Gallery, Projects and General > The Design Shop
DRO for Warco Major mill
PekkaNF:
Checked this option at the far side of the table and there is a loss of travel or loss of measurement.
If the read head is put side of the pilar, it does not interfere with Y-axis travel, but does not read extreme right of X-axis direction.
If the read head is located to read all of X-axis travel, it will clip about 9 mm of Y-axis travel, does not sound much, but it is all located at the useful front part of the table.
So, did a mock up all three options and measured how much things change. No really easy and smart way to do it without any compromise.
Pekka
PekkaNF:
Still dragging my feets....
And got some piece of usefull information: Apparently castings of these cheap mills are not normalized! Amazing. Therefore milling them grooves or pockets is apparently a bad idea. I found one case that mill T-slot table was straight originally, but developed a warp after a pocket for ball screw nut and a grove for ball screw was milled. The warp was in order of 0,1 mm and the grove for the ball screw was 3 mm deep 30 mm wide. Therefore it looks like a bad idea to mill on cast surface. Bugger.
Plan A is to mount:
* X-axis scale behind the T-slot table and accept a 60-70 mm of lost travel distance. I very tempted to use supplied aluminium extrusion to mount the tape, it would provide some protection for the tape and inhibit only 1 mm of Y-axis movement.
* Y-axis is harder, I allready ordered the parts to mount the tape at the top of the table on flat channel - no problem there. But the read head mount would need a pocket milled right into virgin cast surface on the saddle - where it has a great potential to warp TWO axis movement.
Pekka
awemawson:
The warping is obviously relieving stresses in the casting by removing a surface layer, in much the same way that cold rolled mild steel will warp if one side only is milled.
Sadly though if the castings are as bad as you suggest then there will be some warping over time even if not machined :(
It may not be appropriate in the case of your mill, but to overcome a similar space / layout issue on my Colchester Master when Newall came to fit the DRO they used an 'outrigger' to place the actual ball tube well the the rear.
RussellT:
Rather than accept losing travel wouldn't it be better to mount the x axis DRO on the front of the table and do something else so you could continue to use stops. On my mill I added a steel rod below the x axis scale which I can clamp stops to. Although to be honest I haven't made the stops yet.
Russell
PekkaNF:
Thank you Andrew, I know that system and lay-out. I rather use cheap standard parts to this one.
I will deal with the warping when it shows.
--- Quote from: RussellT on January 09, 2019, 06:12:09 AM ---Rather than accept losing travel wouldn't it be better to mount the x axis DRO on the front of the table and do something else so you could continue to use stops. On my mill I added a steel rod below the x axis scale which I can clamp stops to. Although to be honest I haven't made the stops yet.
Russell
--- End quote ---
I was considering it, but it would bring the read head forward and fairly middle - to my work area.
Easiest way to mount the tape on the front of the table would be to remove the measurement tape rule out of groove and replace it with the magnetic tape. Perfect fit. Then it would be possible to use mounting holes of the stationary top block and indicator and replace it with a foot that would double as stop block and read head mount.
But then the tape would be really front of the table, where I tend to use squares, tools, magnetic stand etc. And the read head would be pretty proud and non shielded location.
Second option would be to mount the tape below the current stop into more protected position. That would mean some machining for the magnetic tape (2x10mm grove for magnetic tape + 0,5x16 mm for 0,2 mm stainless steel protective strip. This machining would be into readily machined surface .... maybe minimal chance for warping?
OR bolt on rail for magnetic tape and wonky looking arm. for stopper to clear this.
Another hour or two lego play time on the milling machine :lol: Maybe all would just fit there and convincingly stay out of troubles way.
Pekka
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