Shop Vac Musings

I bought a fancy (cheap) dust collection hose for the shop vac to use with the LR3, made some fittings, took some measurements and am quite uncertain about how it will work!

My current setup - I have a 1250W Ryobi vac, with a cyclone and 24" (7.5m) of hose. It’s a standard 2" hose although I’ve never worked out why its called that because no single dimension bears any resemblance to that number.

All of that hose and bends and cyclone must be putting quite a load on the machine but it seems to work well enough.

Note that when designing my CamLock system, I settled on a 41mm ID as that was the common minimum dimension of the cuff fittings.

The standard hose is nominally 1 1/2" and this is where things get interesting for me.

The factory house outlet end has an ID of 33 mm (855 mm2) The narrowest connection in my current setup is 41mm (3120mm2) but I’m prepared to guess that the total drag in my setup is probably similar to stock.

Now comes the 2" dust collector pipe. It’s actually 2" ID but unlike the vac hoses which are smooth inside, it is a concertina, so the minimum ID is 48mm (1809 mm2) which gives a quite staggering 210% increase in clear area over the standard setup although with a lot of drag.

The drag is such that the pipe wants to contract itself, and the inlet noise is considerable. The suction is such that I have to question what I’m trying to achieve - I’ll have to bolt the entire LR3 down to stop it disappearing up it’s own fundamental orifice! :open_mouth:

Is that unrestricted flow going to mean a premature end for my vac motor? I guess there’s only one way to find out…

Pics left to right - 2" dust hose with Camlock diameter , 2" Dust Hose Ryobi direct fitting, Stock Ryobi tube.