Are there any guides, rule of thumb or otherwise, re the max length of extraction hose vs power of chip extractor?
I want to hook 2 machines up to the same extractor but they will be opposite sides of the workshop.
Thanks
The maths is quite involved to do it properly - I can connect you to some sites with formulae if you need it. But that's probably OTT and could be misleading. Air flow down a pipe is reduced by friction of the air flowing over the pipes wall, so the longer the pipe the more the pressure drop and lower the flow resultant flow. Wider pipes have less surface area to volume so the effect is reduced.
One thing that I found useful is a cheap anemometer.
https://smile.amazon.co.uk/gp/product/B0876SNWW4/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1, you need to make a pipe that fits the anemometer ie 2.5 inches or 63mm and has adapters to your vac and pipework, but that way you can directly measure the air flow from the vac and down any leg of pipe.
BUT there are so many factors that complicate this that its quite hard for a part timer to get everything right. Sharp bends eg 90 reduce flow significantly, flex pipe is much worse than smooth pipe. So like others have said, try and avoid this solution if you can and either go for a portable vac or have two old house vacs if they will work on your tools.
The KEY first thing is to check your vac will effectively eliminate dust from the tools before doing any pipe runs that add complication. I've found the different tools in my garage need different solutions.
If your tools are relatively small makes of dust with small diameter ports, eg router table, mitre saw then the best solutions as others have said is either have a portable vac such as an old house vac or shop vac and move between the two.
My mitre saw had a really badly designed dust port - good saw a Matabo but a bit old, I've had to drill a port into the blade guard and fit a short skirt to get that to work effetely.
Tools with large ports such as bigger table saws, planers etc need large air flow, so check your system will work before adding more pipes. A large table saw may need a low pressure high volume system, that starts to add expense. I found having two vaccs (old Miele 2000w cylinder and old Dyson) on my cheap table saw worked ok once I modified the saw guard air intake to reduce the waste air flow.
I found having at total 3 vacs in my garage has worked quite well, two one end on the TC and then with blast plate for router and mitre saw and one the the other. I do have some pipes in the ceiling connecting the paired ones together. I did try to use just the one vac and a network of pipes but it did not have enough suck on some tools and was too inflexible for moving things about.
One thing that is quite hard to do, is count dust particles. There are home meters on the market but they are very unreliable, I bought the sensor that is common to the main ones being sold found it was not at all accurate, so best to measure dust using a bright torch or laser pointer and see how effective your piping is.
Finally I would recommend you wear a mask for dust making work such as the TC if you have one as dust is so hazadous. Emptying the bin outside as others have said is a good tip.
