RE: Re: [taigtools] RE: Taig CNC mill
Robert, that is exactly what I did. As a journeyman machine repairman, and having five decades of repairing machinery of various types under my belt, I should have know better.
As for the rust, it was swelling and distorting the fit. That was the reason I took it apart to begin with. Take a look at the Taig-Column.PDF in the files section. There is some photo of what I was trying to resolve. Along with photos of the miss applied anti seize
--- In email@example.com, <firstname.lastname@example.org> wrote:The big mistake can be ended with a liberal dose of acetone alcohol and one of those plastic brillo pads, and just keep it clean after that. Anti seize is the worst stuff in the world to put on anything that needs to grip together. The roughened surface from the rust should help hold it.Good luckRobert SeddonFrom: <Don@...>
Date: Thursday, September 12, 2013 3:58 PM
Subject: [taigtools] RE: Taig CNC mill
The tilting column is an issue. When I got my mill, used, the guy had it in his garage and on the floor above he had a salt water aquarium that leaked and dripped on the mill. There was rust in a few places, and one was the faces of the base an column. I cleaned as best I could then smeared some anti seize compound on the faces. Huge mistake. It was still a manual mill at this point, and It showed no problem on the crank handles, smooth as silk, but within the first couple inches of cutting, things were going ugly. When you stood back and looked you could see about a 10 degree tilt to the left. I cleaned all of the anti seize off and that improved things a bunch. My last job was fly cutting some Ancell bar stock and with a very slow feed, but a too aggressive cut, I stalled the spindle and over went the column yet again.
I have been tempted to drill and ream a taper pin seat centered on the faces, a pin similar to the slot plug on my band saw table. I never saw a need for tilting the column anyway. You can fine tune the Z slide to give you an accurate tram with a stiff column.
Just a though.
--- In email@example.com, <editor@...> wrote:
I am just getting ready to use my TAIG for some production work on model engines.
Looks to me as if there is plenty of room to put an automotive hose clamp around the two round sections just forward of the vertical column. I think that might give enough additional clamping force to keep everything in alignment. Certainly the additional leverage from clamping at that diameter will be better than the single bolt.
Another trick that works but is a bit more destructive is to clamp a circle of abrasive paper between the two round sections. Good paper is probably fairly uniform in thickness and should not cause any fore and aft tilt of the column.
--- In firstname.lastname@example.org, <email@example.com> wrote:
mine doesn't shift. i've never done anything at 40 ipm, but i have rammed into clamped work and got hard stopped.
all my slop seems to come from the nylon 4-pin couplers but it is a fixed backlash- not something that is a function of travel.
--- In firstname.lastname@example.org, <email@example.com> wrote:I have a Taig CNC mill that is otherwise working perfectly fine. I can XY true the mill down to 0.2-0.3 mil/inch, the finish of the parts is very good, backlash is less than 1-1.5 mil (I installed ball screws on all three axes), in general not much to complain about the performance.
There is an annoying problem though. As I said, I'm truing the XY axes before any new precision job. No problem, but the X truing doesn't seem to stick. If I measure the error on the X axis after a reasonable short and light job (usually aluminum with 1/4" micro grain carbide 2 flute bits, not more that 1/32" DOC pocketing passes, not more than 30-40 inch per minute feed speeds) is done, I find its up to 2-3 mil/inch, that's 10x the original set up. Obviously, the column is rotating during the workload.
The post screw is tighten to the recommendation (tight but not crazy tight, to avoid bending), it's like the column is always slipping to the right. I tried various tightening, not much of a difference. Also tried lighter DOCs and feed speeds, same problem.
Is there any way to avoid such column rotations and loss of the true setting? I would very much like to have the truing better survive during and between jobs. Or is this to much rigidity to expect from this little mill?
- I use Geomagic Design (was Alibre) to make my drawings. They have PDF publishing capability embedded in the software that generates the PDF.
It is very valuable when you want to show off the insides of something like an engine. You can sweep a cross-section through the model and examine the relationship of everything. You can also measure components with the tool set.
If someone wants to ship me a model of a TAIG (I can accept SolidWorks and some other formats) I can make 3D PDFs of those. Has to be an assembly to be much good for the purpose.