I see two issues.
Your open column design is seriously un-stiff in torsion about the z axis and in simple bending in the x axis. This will be especially true with a bolted structure. You need either two separate closed box section columns or at least to buttress your existing design. At least include it as a possible future modification. It's not possible to say if your current design is stiff enough without doing some comparative calculations. With out these the next best approach to avoid disappointment is to over-design.
The other point is the space between the two columns for the belt drive. A 1hp plus drive needs a minimum pulley size of 50 mm and preferably 70 mm. For a two to one ratio this gives you a large pulley size of 100 to 140 mm. You need to include sufficient space for the belt. A toothed belt might allow higher power transmission at smaller diameters. In addition the unsupported belt length is quite long so at high rpm it may flap around a bit.
Just some thoughts.
Good Luck.
Phil
Originally Posted by Jester966  I'm in the design phase of building a bench mill of similar size to the X3, and I'd like to be able to machine plastics, aluminum, and steel. The plan for the Z-axis (at the moment) is to support the head with eight SR15 bearing blocks on four rails, as shown in the pic below.
Here is a basic model to show the idea:
Is the 15mm rail and SR15 blocks large enough for this size mill? (I've already bought them, so I hope so) Do I really need four rails and eight blocks, or would two rails on the front of the column with two blocks per rail be enough?
The column is built from 1" and 1/2" 1020 steel. Will it be rigid enough to mill steel? Any other comments or ideas on the general design concept?
Thanks |