Hi Tom,
It seems to me that you are approaching this exercise the wrong way round:
You are saying "I intend to do X Y and Z - is this good?" - This question is impossible to answer without knowing what problems the existing setup is giving you and what your target performance is.
A better approach would be to:
1) Identify the specific problems you are currently experiencing.
2) Specify the criteria that will correct your problems (define the forces you intend to put on the machine, the accuracy and precision you require - without real numbers you do not know what you are aiming at and so you cannot identify whether you have achieved your goal.....)
3) Do the sums - calculate the dimensions of the structures you need to build in order to get the required rigidity (all you need is the Young's Modulus of steel and the second moment of area of the sections you intend to use, it is all standard engineering maths that you will find in any textbook)
4) Compare the performance of your proposed mods with your target and check they meet your requirements
If you just stick a load of extra bits on to your mill without having identified exactly what you want to do, how will you know if your mods were a success or a failure?
All the best,
Ian
On 12 Nov 2015, at 20:32, "'Tom Kitta' tom@tomkitta.com [GrizHFMinimill]" <GrizHFMinimill@yahoogroups.com> wrote:
Hello group,I am interested in group's opinion regarding following mod I am planning for my mini mill. The deluxue model I have with brush-less motor has the standard super flexible column. The goal of the conversion is to significantly stiffen both the column and the base in order to take full advantage of the power offered by the motor. I also will increase the Z-travel by about 5 inches and enable the mill to have 4'' inch Kurt style vise without sacrificing any y travel.To stiffen the base I plan to use 2'' by 0.5'' steel bars, welded together for 2x1 bar in a rectangle formation under the current base. The steel frame will also have "paws" extending to the sides to widen the base of the mill & these will be clamped to the bench (rather beefy one weights few hundred #). The box will extend in the back to accommodate new solid column. The old base will be attached to the new one via 4 mounting screws.The new column will be made of 6'' by 4'' C steel that is around 3/8'' thick. If it flexes too much I plan on adding some ribs at the back (I don't think adding ribs to the front to make a double C will be necessary). The C column will connect to the above mentioned base with 2 screws via welded "paws" & via 3 screws to the existing base via existing 3-screw setup. The old column will be connected to the C via 6 screws and will "float" above the base. I can shim the 5 screws to tram the mill.The milling head, weighting about 30# can be supported via counter weight at the back of the C. The electronics of the mill, currently at the back of the column can be moved to the back of the C or side of the C column.Similar mods were done by others with great success - I just modified the materials to fit what I have available locally - I am in the middle of Canada in Calgary & thus I cannot buy much locally.I just want to make the mini-mill as useful of a tool as my 12x24 lathe ... so glad I got that vs. the mini-lathe.More or less I want the limiting factor to be brush-less motor power & the mill head ...Ideas for improvement? Comments?Tom
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