1 Attachment(s)
TS Overhead Guard Extraction
Hi Guys:
I'm getting closer to building my own TS overhead guard and extraction. As you know, I have a Felder overhead arm and blade guard, namely the huge green job that does a very POOR job of extracting dust, although it looks pretty!
I do very much like the "boom" arm mechanism which does a great job of giving me something on which to hang my home-made guard. I'm heavily influenced by the guards of BobL and John Samuels, and am building something similar.
Here are the features I'm thinking about -- with questions. I have not built anything so I am completely open to suggestions. Thank you!
1. I'm thinking of using polycarbonate sheeting for most of the guard. I have a quantity of 8mm and 12mm sheet which should do the job.
2. Make very shallow dados to strength the guard joints; superglue together. Do I need to reinforce with screws?
3. The support mechanism will be a simple piece of wood with some Kipp levers to tighten. Nothing fancy, just a simple up and down overhead mechanism. The Felder boom arm provides the necessary "right to left" adjustment.
4. I'm thinking about bringing in 140mm flex along the boom arm and putting this directly overhead and forward as far as possible to give the maximum amount of suck up front where the dust is. I know that 140mm is too big (normally) but I do not use my saw for cross-cutting -- only for ripping -- so I don't think I'll have a problem with small offcuts becoming a problem...but I'm open to your views.
5. One of the main reasons for the 140mm is so that it will "balance" with the 160mm I have under the table. Both go back to a 200mm ducting. I was thinking of putting a gate on the 140mm just to tone it down if I have to. Is that a good or bad idea?
6. I've noticed that BobL says to make the shroud longer to avoid turbulence. I'm wondering whether the 200mm I've sketched is enough. Perhaps 300mm or 400mm? I was just thinking of keeping the guard more compact that was all.
7. John Samuels commented that he wished he had made a seamless front section for better viewing. That sounds like good advice!
8. Many have commented (including me) on the problem of ripping a piece to width by just trimming off half-a-saw-blade, for example, such that a stream of dust/chips is emitted on an angle and must be stopped physically -- no sucker is strong enough to capture it. For those who have bristles around the base of their guard - do you still recommend them? I'm thinking about adding a second piece of polycarbonate, perhaps 3mm (?), which is moveable on the left hand and front of the guard (my fence is to the right of the blade). This would allow me to lower (say with butterfly nuts on a machine bolt) the polycarbonate to suit the thickness of the material being ripped. This means the guard can hover just above the material being ripped, but allow the left side of the guard to "drop" all the way to the table. Do you think this will work?
9. The last thing that bothers me is getting appropriate airflow through this thing. With the guard adjusted really close to the stock and saw table, there is not a lot of scope for airflow. Would it be a good idea to use a 50mm forester bit to cut some big holes in the poly? Perhaps on the right side of the guard (closest to the fence)? What about at the back of the guard? I don't know... and would love your collective input! Thank you.
Attachment 331266