Can't remember if this was on the original Woodhaven but I just came across my Thien separator build so thought I'd share it
Thien separator build:-
Working on the principle that I wanted an air tight container to minimise loss of suction I managed to get hold of an airfreight drum made for transporting batteries.
I liked this drum as not only was it robust with a locking ring to hold the top secure but it also had a built in rubber gasket in the rim of the lid.
The first thing I did was to find the center of the lid for the connection to the extractor, this I did with dividers
With the center marked I drilled a 50mm hole, I also drilled a hole near the rim for the dust hose elbow, the fittings I'm using are 50mm mini gutter down pipe fittings.
With that done I turned my attention to the baffle, this is made from 14mm plywood, I started by cutting half way through the ply to outline a 14 inch disc the internal diameter of the drum.
I then measured round the circumference divided the measurement by 3 & marked this measurement on the edge of the circle, the router was then moved in 1 1/8 inch towards the center & an arc cut all the way through the ply 2/3rds around the circumference.
The router was then moved back to its original position & the outer circumference cut all the way through. Unfortunately I forgot to take a photo of the finished shape but this is the baffle when bolted in, showing the finished shape
The baffle was then placed in the drum held up with packing, the lid was placed on top & the holes for the bolts drilled.
The holes were filed roughly square & the underside cleaned up with the grinder.
After which PTFE was wrapped around the bolt heads, these were secured to the lid with nuts,packers & locking washers & the baffle fitted temporarily.
Finally for today the 2 fittings were epoxied in position.