# Box sash design: parting bead



## RobinBHM (11 Feb 2021)

Whenever Ive made sliding box sash windows, I always have the same issue.

The problem is what tolerance to give on the parting bead groove.

Generally I machine the groove to 8.8mm for an 8mm bead - but the tightness of the bead varies - from slack Alice to Tommy tight.

I spray 1 primer coat and 2 top coats with waterbased joinery paint




Anybody find the same issues?

I believe Mumford and Wood do tapered groove and tapered parting bead - which is an option I guess


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