A little challenge

dusty · Post by **dusty** » Wed Jun 30, 2010 3:50 pm

has again been accepted.

It has been stated that before a problem can be resolved, it is necessary to understate exactly what the problem is. The dust collection system used with the Mark V being inefficient is not the problem. It is a symptom of the problem. The pile of shavings that Mark challenged us with is another statement of the problem.

Following this line of thinking, I set out to find out how the sawdust managed to escape from the lower saw guard. What is the escape path? To determine the answer to this question, I taped holes closed, built and installed reflectors, varied adjustments on the lower saw guard and finally decided I had it identified.

[ATTACH]9422[/ATTACH]
This is the deflector that I installed

[ATTACH]9423[/ATTACH]
The Deflector installed in the lower saw guard

[ATTACH]9424[/ATTACH]
The hole is blocked on the left side

[ATTACH]9425[/ATTACH]
The hole is blocked on the right side

At this point, it is my opinion that the objective is being approached.

dusty · Post by **dusty** » Wed Jun 30, 2010 3:59 pm

It appears that Mark and I have identified the same path for the escape of saw dust. I'm just a little confused as to why Ed doesn't have saw dust escaping the same way.

In my last image, note the piece of aluminum under the thumb screw. There is one just like it on the outfeed side. I also had to seal the hole that is under there.

dusty · Post by **dusty** » Wed Jun 30, 2010 4:04 pm

This is another escape route that I experienced. I don't know about others but it seems that this is also universal to to most of the late model dust collectors. The dust shown here escapes through a crack between the two pieces of the lower saw guard. I blocked this with a piece of this weather stripping. Actually, it is two sided tape with the cover not removed on one side.

[ATTACH]9429[/ATTACH]

Take note of still another escape route (mentioned earlier) next to the thumb screw.

Ed in Tampa · Post by **Ed in Tampa** » Wed Jun 30, 2010 4:08 pm

Dusty
I know why I can never put my lower guide on level. I went and looked and sure enough the front of it is nearly touching the bottom of the table. That along with the fact I usually expose more of blade probably closes the gap even more.

dusty · Post by **dusty** » Wed Jun 30, 2010 4:12 pm

Ed in Tampa wrote:Dusty
I know why I can never put my lower guide on level. I went and looked and sure enough the front of it is nearly touching the bottom of the table. That along with the fact I usually expose more of blade probably closes the gap even more.

I am certain that I do not understand your statement. There are portions of my lower saw guard that contact the underside of the table as well. In fact, the spring loaded sliding gate is pushed down by the table.

Is there something that I am missing? Is this comment in regard to a specific image that I have posted?

Ed in Tampa · Post by **Ed in Tampa** » Wed Jun 30, 2010 4:29 pm

Dusty
When you put the lower saw guard on it hangs from the quill shoulder. When I put mine on I usually try to get it level but never do which means the front of mine is higher (closer to the table). Also when I cut I usually have more of my blade exposed so the table is almost hitting the front of the lower saw guard where you put the extra shield. I think that is difference.

dusty · Post by **dusty** » Wed Jun 30, 2010 5:13 pm

Ed in Tampa wrote:Dusty
When you put the lower saw guard on it hangs from the quill shoulder. When I put mine on I usually try to get it level but never do which means the front of mine is higher (closer to the table). Also when I cut I usually have more of my blade exposed so the table is almost hitting the front of the lower saw guard where you put the extra shield. I think that is difference.

I relate to all that you say. I believe we have exactly the same configurations. A couple to pictures taken from the right position will reveal that.

I have scratched a mark in my headstock and lower saw guard to aid in alignment so that when the table is lowered it contacts the movable gate on the lower saw guard evenly.

The area where I located the dust deflector is very close to the saw blade. Without going out to check, I would say there is less than a 1/4" clearance. Maybe more like an 1/8".

mbcabinetmaker · Post by **mbcabinetmaker** » Wed Jun 30, 2010 8:08 pm

I often place my saw guard on the quill shaft loosely and go ahead and tighten the blade. Then I will move the table over and lower it just enough to compress the saw guard to a level position and just reach under the table and tighten it up. Level every time this way.

On to another observation that I made today. The extension piece that mounts to the table itself has about a 3/4 inch gap at the top. Under a heavy cutting load I believe that is also a problem.

shipwright · Post by **shipwright** » Wed Jun 30, 2010 9:04 pm

Don't know why mine works so well and can't check until I return to AZ in Oct. Maybe the DC pulls more volume than the SS one? I know that I had a great reduction (80-90%) in chips in the indicated area when I added the DC (and remembered to turn it on), and more importantly the airborne dust was absolutely GONE.

Paul M

dusty · Post by **dusty** » Wed Jun 30, 2010 9:20 pm

mbcabinetmaker wrote:I often place my saw guard on the quill shaft loosely and go ahead and tighten the blade. Then I will move the table over and lower it just enough to compress the saw guard to a level position and just reach under the table and tighten it up. Level every time this way.

On to another observation that I made today. The extension piece that mounts to the table itself has about a 3/4 inch gap at the top. Under a heavy cutting load I believe that is also a problem.

If you are talking about the space between the underside of the table and the tie bar guard (155), I don't believe that contributes to the escaping dust. I have taped this closed and found no difference.

If you sit down under the table and watch the tie bar guard as you lower the table, you'll see that it slides right by the lower saw guard to block free air flow. Now take that tie bar guard off and operate the table saw and you will need a broom.

Paul, if your dust collector provides significantly more air flow than a standard DC then I am not surprised that you have no dust collecting on the carriage.

If I run without the DC operating, I get a significant face full of dust coming off the outfeed side of the blade and being thrown right at me.