On 15/04/2021 14:03, John Rumm wrote:
On 15/04/2021 09:08, wrote:

I think about improving DE from time to time (whenever I'm cleaning-up
after a messy job) but don't seem to find the necessary tuit. My saw
has a small hose from the crown guard (hinged on the riving knife)
that goes inside and joins the under-saw 50mm hose to come out to a
100mm port that I connect to my 2HP HVLP cyclone extractor. I
frequently operate without the crown guard(!!) so plug the crown guard
hose.

One of the problems you might find with the smaller hose up top is that
its not as well suited to the HVLP extractor because of its higher back
pressure. Some people find running a separate LVHP collector (e.g a shop
vac style collector) just for the top hose works better.
Yes, a little experimentation makes it seem that LVHP is better for both
top and bottom with the current internal plumbing.

I'd like to devise a pivoting and self-adjusting crown guard that's
suspended from a hollow tube that's attached to the saw in some way
and can be used for DE. The crown extraction would be connected to the
under-saw hose with a throttle'able Y connection and then go to the
LVHP extractor.
Issues: how to make the suspension rigid enough (but allow the saw to
be moved), how to improve collection beneath the saw, ...
Suggestions and comments invited.

There are quite a few examples of this kind of thing about - most are
quite large since they need to reach over the saw from far enough away
as to not curtail the maximum size of sheet you can process.

https://wayofwood.com/diy-tablesaw-o...d-blade-guard/

or

https://www.axminstertools.com/axmin...e-guard-104504
Thanks for those - thought-provoking and similar to what I had in mind
(but I can't believe Axminster sell many at that price)


You may find that building a cowl to mount under the table to enclose as
much of the blade as you can (either fixed to the trunnions so that it
an tilt, or just wide enough that it can accommodate the tilt, and
connecting that to the HVLP collector will increase the air speed under
the blade high enough that it can capture everything flying off the tips
of the blade, before it gets a chance to escape again.

My saw was basically designed to just dump dust into its base for later
manual removal. However I added a 4" port to it. Running that into the
HVLP does reduce the amount that gets out of the case - but not
completely. (not helped by other piercings through the case like by the
blade height adjust wheel that let air be sucked in via alternate routes).

I found just adding a bit of tube split round the blade where it exits
the underside of the table, was quite effective on this contraption:

http://wiki.diyfaq.org.uk/index.php/...awbench#In_Use

That might not be too difficult to mount such that it moves in sympathy
with the blade tilt.


I'm moving towards using a good LVHP almost everywhere (with cyclone,
50mm plastic ducting and home-made blast gates) and only using the HVLP
for the planer thicknesser, and maybe the (rarely used) wood lathe. I
suppose, if I ever get around to inventing something, a dust catcher for
the chop saw might be HVLP as well.