Cartridge Filter Upgrade For Old Dust Extractor
Before and After - old bag filter on the left and new cartridge filter and larger dust bag on the right.
June 27, 2020
When I set up the workshop a couple of years ago I bought this second hand Axminster ADE 1200 extractor as a temporary ‘fix’ for my extraction needs. Fastfoward to now and I’m still using it… Anyway during lockdown I’ve been reading about extraction, ducting, air flow and filters - all the good stuff - and I reckoned that it must be possible to improve the rather lack lustre performance of the old ADE 1200.
The problem is that this particular machine has ridiculously small port sizes for the dust bag and filter (275mm diameter) which seriously limits its usability. When attached to the planer the dust bag fills in a few minutes and replacements are hard to find that fit properly. The 5 micron cloth filter quickly clogs with sawdust and does a really good job of throttling the airflow to a feable wheeze.
I figured that what I needed to do was improve the filter and make the dust bag capacity larger if the extractor was going to continue to be useful. A quick search on the ‘net for cartridge filters ended up at Charnwood who stock two standard sizes of cartridge filter that looked like they would do the job. I ordered the Charnwood CF1519 a 1 Micron filter that comes as a kit with cleaner paddles, handles and fixing strap included - for a very good price! The only problem was that the cartridge filter is designed for a 370mm diameter mounting port… too big for the ADE 1200.
The Axminister ADE1200 only has a 275mm diameter mounting port. The cartridge filter needed a 370mm mount to fix to.
The solution was to create a ‘donut’ collar from MDF that would enlarge the diameter and allow the new filter to be fitted. This was screwed into place and two notches cut to allow the filter to seat properly.
In order to increase the diameter of the metal port, I glued up a couple of scrap mdf squares and then cut a ring out of it (275mm inside diameter and 370mm outside diameter). I also had to cut some notches into the ring to make the cartridge fit. Then I screwed it in place (I’d glued dominos at each mounting point to give the screw something to bite into) and sealed the gaps with silicone. Another similar ring was fixed to the underneath port for the larger dust bags. On the recommendation of Richard at Charnwood - I routed a lip on the edges of the rings to help the metal straps hold everything in place. Fitting the cartridge filter was straightforward - it’s a simple push fit - and the metal strap moulded the rubber gasket firmly to the mounting ring . Same for the collection bag underneath.
It was with some trepidation that I switched the extractor on for a test run - I was half expecting the cartridge filter to shoot off the top.
Would there be any improvement in suction and air flow? Absolutely - I could tell straight away that the performance had improved and that the new filter was allowing more air to flow through it thereby improving overall efficiency. A few non scientific tests (sticking my hand over the flexi pipe and then sucking up some shaving etc ) verified my findings - maybe as much as a 50% increase in suction over the old cloth filter bag. And best of all the paddle works to clear the filter from the inside. Time will tell if performance is maintained at this level as the filter becomes used and worn…
Additional strengthening was required due to the extra weight of the alterations - a new floor and rear upright add much needed rigidity.
Heavy duty spring clips hold everything in place - a small lip on the waste bag donut helps keep the bag from slipping.
The down side to all these improvements was that the already flimsy metal frame was at serious risk of collapse with the additional weight of the two mdf rings and the hefty cartridge filter. I could see that the floor pan was flexing and the cantilever frame was drooping quite excessively on the open side. Some 18mm plywood and a length of CLS were fashioned into a stand and bracket with another piece of plywood mounted to the floor pan to add additional support. Once reassembled with the cartridge filter and dust bag the stand proved to be far more solid with considerably less flex.
I’m happy with the results - performance of the aged Axminster ADE 1200 has improved considerably, the filter is robust and easy to keep clean and the dust bag has doubled in capacity. Workshop air quality should will also be improved as the 1 Micron filter traps fine dust particles that passed through the old filter. There’s life in this old machine yet…