I thought the 278-Z was a 1/4" (6.35mm) cutter. The shaft measures at 6.35 but the slot it cut in aluminum measures at around 6.05mm. So it messed up my part, but what should I actually expect the tool to be and is there a drawing? I’ve only used the tool a few times, no damage that I can see under the microscope.
Thanks!
The #278Z is a single-flute cutter as noted in the specs on the shop page:
Tools will deflect in tougher materials — did you run a “spring pass” to minimize the deflection?
Photo showing the stock and part and how it was clamped? How did you measure?
If it’s still clamped in place try re-running the file?
This was a tool width slot in Aluminum, multiple passes to hit a 7mm depth.
Measurements taken with an absolute Mitutoyo digital caliper set like this one: Mitutoyo ABSOLUTE Digimatic 6" Caliper – Area 419
And also the swearing, “why doesn’t the mating part fit” test.
Picture, I’m probably not allowed to share. But it had an MDF spoil board on the back and was held down all around the edges with those green plastic t-slot clamp things that you sell. The stock is aluminum flat bar 6.35mm thick 19" x 5". Slots were off, pockets were off the same amount. There was no stock to leave or other settings like that in the file for these operations. Other cuts with an 1/8" tool were accurate.
The recommended DOC is much less than what you are doing.
Slotting is the most abusive tool path because you are contacting both sides of the bit.
If your intended slot is near 1/4, you might want to use the 1/8 bit and make a Pocket.
It takes a long time with the recommended speed and feed, but the results are good.
Cutting aluminum dry takes a bit of patience.
Listen to the cut and adjust accordingly.
Thanks for the advice Jim. I was referencing that slot because my adaptive slots and other features came out undersized with this tool. So I set out to try to measure what its size really is. Honestly I thought I’d post this question and learn the tool wasn’t really 1/4" at the cutting section.
Try a finish pass. Honestly I don’t try to make things fit