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Post by Knight Woodworks on Sept 22, 2015 16:29:22 GMT -5
Nice Tom, I've ordered one as well. Wouldn't get mine until Monday.
John
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questa
Junior Member
Posts: 62
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Post by questa on Sept 22, 2015 17:27:10 GMT -5
Congrats to Tom and John
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Post by jonathan on Oct 8, 2015 15:32:53 GMT -5
Continuing on the dust collection... Since using 2 extractors I don't have any dust blowing out at the riving knife anymore. Here's a short vid cutting 2 laminated boards of 18mm MDF. Most intrestingly, what escapes below the table.
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Deleted
Deleted Member
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Post by Deleted on Oct 8, 2015 21:11:01 GMT -5
Very nice jonathan ! The unspoken detail in the first second of the first video is brilliant ,will try that soon .
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Post by jonathan on Oct 9, 2015 3:50:27 GMT -5
Might not look like much, but collection is good! There's very little of that MDF that escapes. Had the top blade guard extended 5cm further over the front of the blade, I think there'd be 0 dust left on the table top.
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Post by erik on Oct 11, 2015 12:23:07 GMT -5
Wow, talk about dialing in, thanks for sharing jonathan.
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Post by jonathan on Oct 21, 2015 7:42:45 GMT -5
I did a few more setups and did few measurements with an entry-level Extech anemometer. The CFM ratings seem low and I'm not sure how reliable they are. I held the anemometer vane against each hose opening in the exact same position and noted the highest value I got with each measurement. I suspect the low values are because the 70mm diameter vane is much bigger than each of the vacuum hoses and because some of the support struts for the anemometer's vane block part of the hose. Therefore it's possible not all the airflow got measured? I'm by no means an expert at this. However due to the way each hose and setup was measured in an identical fashion I do believe this provides a reliable baseline even if the CFM values seem a bit low.
The results really surprised me because on paper Bosch states 150CFM vs 138CFM for Festool.
By simply sawing on the Erika 85 I had much better results in dust collection with the Bosch than the Festool but thinking about it now, the Protool wasn't fitted with a clean bag at the time, instead it was approx 20% to 25% full. I didn't think such low contamination of the bag would make a difference, so I didn't take it into account. Now that I see these numbers, I've replaced all my bags with brand new ones for these measurements.
Here are the numbers:
Scenario 1: we use a single vacuum
* We see that both vacuums have near identical performance. Without a dust deputy in the mix, the Bosch has a tiny edge. When I loop everything through a Dust Deputy, the edge goes to the Festool. * The Dust Deputy causes a significant loss in performance for both vacuums.
Scenario 2: We use 2 vacuums. 1 dedicated to the back & another dedicated to the blade guard
* Again, both vacuums near identical performance.
* Dust Deputy still causes big loss in performance.
In any case, take these numbers with a pinch of salt. The real-world result should become clear to me once I actually test these configurations by making sawdust and see how much isn't collected.
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Post by jonathan on Oct 22, 2015 14:47:28 GMT -5
Another day, another test.
These tests start from the premise of using 2 vacuums. One dedicated to the back and one to the blade guard. In my opinion it's worth it because it effectively almost doubles the airflow you get at both extraction points. These measurements focus on the best setup for the port at the back of the saw and the use of a Dust Deputy cyclone.
I wanted to know if I would get more CFM at the back of the saw by going to it with a 50mm hose vs going directly to it with a 36mm hose. To connect a 50mm hose we'll need the Y-connector, so I taped off the smallest of the 2 pipes on the Mafell Y-splitter.
- Bosch GAS 35 L --> 50mm hose 125cm long --> Mafell Y-splitter smallest pipe taped off ==> 52.3 CFM
- Bosch GAS 35 L --> 36mm hose 150cm long ==> 53 CFM
There are no gains to be had by going to the Mafell Y-splitter with a 50mm hose and taping the smallest of the 2 pipes off. If you're going to dedicate a vacuum to the back port of the Erika, just connect to it directly to with a more manageable 36mm hose.
Now that I was measuring 50mm & 36mm hoses, I was also curious to see if going to the Dust Deputy with a 50mm hose had any significant gains over going to the Dust Deputy with a 36mm hose. Because the connections on the Dust Deputy have a larger diameter than a 36mm hose connector, it should be better with a 50mm hose, but just how much?
- 50mm hose 125cm long --> Dust Deputy --> 36mm hose 50cm long ==> 44.4 CFM
- 36mm hose 150cm long --> Dust Deputy --> 36mm hose 50cm long ==> 40.1 CFM
When going to a Dust Deputy cyclone, always start off at the vacuum with a 50mm hose. When you come out of the cyclone again, there are no gains to be had by using a larger diameter hose than the diameter of the cyclone outlet.
And here we see again, the impact a Dust Deputy has on the airflow. I wonder though how the Clearvue CV-06 mini cyclone compares to the Dust Deputy in CFM drop measurements. I'm tempted to import one, but for something that might not really pan out, it's going to be damn expensive with the shipping and import charges I don't suppose anyone else on here has both cyclones and an anemometer? Oh yeah and some spare time...
So I'm pretty sure what the optimal setup is now. I don't think any of this will come as a big surprise to anyone, but it's nice to see it corroborated with measurements.
The only thing left to test now is to see how full a vacuum using fleece bags can get in order for the airflow to drop to the same level or below the airflow level of when you also make use of a Dust Deputy.
We all know a table saw creates a lot of dust and the vacuum bags fill up fast. Is the drop in performance caused by the Dust Deputy worth the cost savings in bags?
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Post by jonathan on Oct 23, 2015 19:00:05 GMT -5
Well I've done about all the measuring I can bear for now. I've put in an Excel spreadsheet and added some graphs. PDF file download:
Mafell Erika 85 Ec vacuum configs with Bosc....pdf (298.09 KB)
* Scenario 2 is the most efficient/performant setup. Dedicate a vacuum with short 36mm hose directly to the port on the back and dedicate another vacuum to the blade guard on top. * This is also the configuration that's best suited for use with a cyclone. Performance drops too much in the other scenario's to make a cyclone worthwhile in my personal opinion.
* Using a Dust Deputy in scenario 3 results in terrible airflow values very close to using a single vacuum without Dust Deputy. When not using a cyclone in scenario 3, the airflow at the back is the same as a dedicated vacuum to the back in scenario 2. The CFM at the top however is lower in scenario 3 compared to a dedicated vac in scenario 2. * Throwing a Dust Deputy cyclone in the mix here is completely counter-productive as the airflow drops to the same levels as with a single vacuum in scenario 1.
HOWEVER, in scenario 3, by combining the 2 vacuums (no cyclone) you get a much larger filter surface with 2 fleece bags and 2 pleated filters. Theoretically it should take longer for both bags to clog up and it would take longer for the performance to drop as both vacuums fill up simultaniously.
This is the kind of collection you can expect with this setup:
So there it is. Use the information to your advantage I'd say...
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Post by holmz on Oct 24, 2015 18:45:39 GMT -5
... And here we see again, the impact a Dust Deputy has on the airflow. I wonder though how the Clearvue CV-06 mini cyclone compares to the Dust Deputy in CFM drop measurements. I'm tempted to import one, but for something that might not really pan out, it's going to be damn expensive with the shipping and import charges I don't suppose anyone else on here has both cyclones and an anemometer? Oh yeah and some spare time... ... XMAS is coming up. You probably just need the top part, as they have buckets where you are at. ??
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Post by reflector on Dec 11, 2015 0:52:22 GMT -5
Hi, first post here and soon to be Mafell owner but not of an Erika. I post on Bethepro occasionally and I've been doing modifications on my Bosch 4100 and I'm hoping some of things I've been doing would be helpful: bethepro.com/forums/topic/4100-dust-control-modifications/Looking at how the Erika has the shroud extended up but not fully to allow for clearance on the tilt of the sawblade, couldn't you put something that'd closer join the shroud to the table? The smooth underside looks like a perfect candidate for using something like the soft vinyl/plastic material I've been using, it'd just have to extend up a little and have a tiny bit of pressure against the underside of the table. That way it wouldn't really drag when you use the pull function but it'd focus all the airflow right up at the underside of the table where the cut is at.. That's eliminate most of the dust below.
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Post by jonathan on Feb 16, 2016 13:03:56 GMT -5
Still dissatisfied with the Erika 85 dust collection I decided to take it apart a little and have a closer look inside. Took some pictuers while I was at it and now we clearly see why the dust collection is such as it is... ( Click images to enlarge) Blade all the way up Blade up 25mm Blade all the way down All the way down. Here you see the big hole for the motor/arbor, from which air is pulled in by the vacuum. If it pulls in air from here, it isn't pulling it from where it should, namely at the front of the shroud. All the way up. When the blade is all the way up, it's even worse. Same thing with the other side of the shroud. Air will be pulled from the hole used for blade changing instead of at the front of the shroud. Visualing it in reverse, there's nothing inside the shroud to "guide" the airflow to the point of cut. It's easy to see how the air just comes from straight up around the riving knife and from the big hole hole around the motor/arbor, but not from where it should come, the front of the shroud. I'm going to do an attempt at making some plastic strips and hot glue them in place to help guide the airflow to the front and see what it does... As a closing note, it would've been nice had Mafell engineered the shroud to flip open much like the MT55cc does for blade changes. That way they could've done this straight out of the factory on one of the side panels of the shroud, it kind of looks like there is a lip on the inside, but as you can see in the pictures, there isn't any. But that is where I'm going to try and glue something in.
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Post by reflector on Feb 16, 2016 14:48:16 GMT -5
On my Bosch 4100, when the blade is fully lowered there is a significant void beneath the guard to the vacuum/bag port. From my experimentation, there's more airflow wasted towards the rear of the riving knife where the blade will drag air upwards instead of directing airflow from the front of the housing where dust is extracted. There's also significant amounts of space towards the front of the blade on the Bosch 4100. I have considered using a piece of flexible material and using double sided tape to have it draw more of the air towards the front of the blade much like the MT55cc.
I am more than sure the MT55cc's kind of "internal ducting" would significantly improve dust collection (especially at end of the cut) on the Erika 85 Ec. The Erika already works better than my 4100 in the base form and I had to enclose the entire lower side of the shroud to the table to prevent the 4100 from dumping dust out form beneath.
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mattuk
Junior Member
Posts: 79
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Post by mattuk on Feb 16, 2016 14:52:08 GMT -5
Great work Jonathon. I have two starmix under the Erika85 and have some dust escaping into the workspace like yourself. My glue gun arrived yesterday. Do you think there is spare for a zero clearance insert to be fitted at the top of the shrouds with a little more space at the front to help concentrate the air flow ?
I am going to have a look at creating a cover ( possibly sprung like a lens cap ) to cover the arbor hole.
I look forward to your findings. Cheers. Matt
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Post by GhostFist on Feb 16, 2016 14:52:44 GMT -5
Interested. Good luck. Love your hard work!
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