4 ms·
Try switching from woodworking bits to metal working bits. An end mill will be 0.2500 with probably a minus tolerance of a tenth or two. The wood bits might be
by vidanay 9y ago
Try switching from woodworking bits to metal working bits. An end mill will be 0.2500 with probably a minus tolerance of a tenth or two.
The wood bits might be undersized to accommodate tearing of the grain and sanding.
- abakker 9y agoThanks! The issue with metal working bits is # of flutes/flute geometry - the chips need to be too small to get a good finish, or the feed rate needs to be too high. The "woodworking" bits I use are already pure carbide, high quality bits. my method these days has been to bore a small test hole into a piece of delrin with each new bit, and test that hole with a set of .001" increment pin gauges. Using that number has proven to be good enough for my purposes. Note that this problem is only present where the cutting diameter is nominally the same as the shank diameter. If I buy .5" shank bits with a .25" cutting diameter, they are perfect, but 2x the cost.
- DannyBee 9y agoFWIW: I've ordered 0.25 and 0.5 inch wood bits from onsrud, harvey, vortex, etc,and the bits are right to my ability to measure them. (IE i can measure them to be within 0.0005 of correct size easily, and better than that better tools on the uncoated bits i have). I'm not sure who you are ordering from. (as for feed rate too high to use other geometries not sure what IPM you can drive that thing at. I would expect you could easily do 300-400ipm, which seems more than enough. I can get a very smooth finish from metalworking bits with no problem)