On today’s show we’re talking about: our woodworking predictions, our woodworking goals for 2019, stickering barrel staves, rite of passage projects, clamping pressure, sanding dovetails, dueling dust collectors, what we watch/listen to, getting back into woodworking after a layoff.
Voicemails
- John got a hold of a bunch of green barrel staves and wants to know how to store them
- Michael is uncertain how much clamping pressure to apply
- Michaels asks how we sand our dovetail corners
- The mystery of of dueling dust collectors
Emails
- Rachel asks what we think about skipping rite of passage projects and just building what she wants
- Jason wonders what we actually watch for woodworking education and entertainment
- Stump asks about the best way to get back into woodworking after an extended time away
2019 Predictions and Goals
The boys discuss what they think will happen in the next year to our little woodworking universe. They then discuss what our personal goals are related to their own woodworking.
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10 replies on “WT455 – Woodworking Predictions for 2019”
Just had some kickback on the dueling dust collectors. Without going too deep into fluid dynamics and pump laws, connecting them in series will increase the system pressure (suction) and connecting them in parallel will increase the volumetric flow rate (cfm). Without increasing the diameter of the main line you will experience a significant amount of head loss though. Just thought that needed cleared up a bit. Thanks for the show.
This is the same question I asked Oneda (2 collectors in parallel). Their reply was the volume of air would be the combined amount. The suction would be the same as the lowest one.
Darn, another pump guy beat me to it.
Yes, connections in series will increase head/pressure and connections in parallel will increase flow/cfm. If you have more experience with electrical, it’s the same as voltage (pressure) and current (flow/cfm).
Regarding the comment on the podcast that it can’t move more because the pipe is the same volume, it is the same volume, but it will increase cfm because the air velocity will increase. As Elijah says, there will be increased losses in the piping because friction/head loss increases with velocity, so increasing the pipe size might be a good idea.
Operating in parallel can cause some other issues, but if the two systems are identical and they aren’t discharging into a common headed, it’s probably not a concern.
Full disclosure, I’m a pump engineer, not a fan engineer, but in general the two are analogous from a physics/engineering standpoint.
The system will default to the more powerful collector anyhow. But at least in a parallel system it comes down to piping. The system needs to be an exact mirror image of the other. Without doing that your gonna wind up emptying one more then the other
Isn’t the obvious solution being overlooked here? If you have two dust collectors put them on either side of the shop and have them hooked up to different tools..
I don’t think that was the point. I’m pretty sure this was a more theoretical question. But if I were in that situation, I too would just have them hooked up separately.
Kickback – Feedback on the staves issue.
I’m wondering if the caller was referring to the fact that the staves all have a curve to them, so you can’t lay them “flat” to sticker, because they have a curve to them?
I was thinking the exact same thing about the staves – that they might be curved, making sticking them tricky.
I studied this quite a bit, including discussing it with an expert who had tested this theory extensively. It was several years ago, so I don’t recall all of our conclusions, but simply put- two dust collectors working together WILL pull more air, but it’s a bad idea.
If you put two DC’s in parallel (next to each other, connected to the same line via a wye) you risk one starving the other and potentially overheating the motor. If you mount them in series (one pulling air through the other) you risk one pulling too much air through the other, increasing the impeller speed and overheating the motor.
The first scenario is the most dangerous, according to the expert I consulted with who tested both. He considered it a fire hazard. The second scenario did work in our testing. Even so, we did not run it for extended periods of time so I would not recommend it because I can not say if there’s significant potential for damaging your motors or causing a fire.
Bottom line- the benefits do not outweigh the risks and you shouldn’t do it. Instead you could use those two collectors to create two independent zones in your shop to reduce the length of the ducts required to reach your machines.
-James Hamilton (Stumpy Nubs Woodworking Journal)
Hey Marc, can you link to the podcasts that you guys subscribe to so we can check them out as well. Did a search on “From the ground Up,” who would have thought there would be that many in iTunes wowzer!
Love WoodTalk, keep up the great job guys!
Thanks,
Troy