Holes and fillets
Use the real hole tool instead of a circle and a cut, and put fillets where they actually belong in the list.
By the end you can
- Create standard-sized holes with the hole feature rather than an extruded circle
- Place fillets and chamfers late in the feature list and explain why
- Identify where a fillet is structural rather than cosmetic
You can cut a hole with a sketched circle and a remove extrude. The hole feature exists because that throws away information the rest of your workflow needs.
What the hole feature knows that a circle does not
A cut circle is a void. The hole feature is a hole: it carries a standard size, a fit class, a depth condition, and whether it is countersunk, counterbored, or tapped.
That metadata pays off in three places:
- Drawings get automatic hole callouts —
⌀5.1 THRUappears without you dimensioning it by hand. - Consistency — pick M5 clearance once and every hole that should match it genuinely matches.
- Changes — switching the whole robot from M4 to M5 is editing a hole feature, not re-dimensioning forty sketched circles.
For FTC specifically
goBILDA runs on M4 hardware in a 8 mm grid; REV uses M3 with its own pattern. Set the hole standard once and let the feature keep you honest, rather than remembering which mechanism used which.
Fillets and chamfers
The rule that matters is about position in the feature list, not about radius.
Fillet last
Add fillets near the end. A fillet applied early rounds an edge that a later feature then needs to reference — and when that edge no longer exists in the form the later feature expected, the feature fails.
There is a second reason. Fillets are the features most likely to fail outright when geometry changes underneath them. Keeping them at the bottom means a failure is isolated and obvious rather than cascading through everything below.
Where a fillet is doing real work
Most fillets on a competition robot are cosmetic. A few are not:
- Inside corners on a load path
- A sharp internal corner concentrates stress and is where a plate cracks. A fillet there is structural, and worth its weight.
- Anywhere a wire or belt passes
- A chamfer on a hole a wire routes through stops the edge cutting into insulation over a season of vibration.
- Edges people handle
- Drivers and pit crew grab the robot. A chamfer on an exposed sheet edge is a safety feature, and inspectors do look.
Check yourself
Why prefer the hole feature over sketching a circle and removing it, for a bolt hole in a drivetrain plate?
Next
One hole is rarely one hole. Patterns.
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