This really sucks big time

[bogmonster]

You are not missing anything - and I started with the same concern. I have not seen any others using the same design as mine before, as you say most have the rotary coupling on the tail stock side. My old lathe had a hollow spindle with a cross drilled spindle lock right through meaning it could not hold a vacuum. That meant either a rotary coupling on the headstock end with suction at the headstock end (tricky to DIY make) or pass a tube through. There are a number of options out there where the tube spins with the spindle and a coupling on the tail stock end but they all looked a PITA to instal and remove so I gave this a go first. Some stay in place until you need to use the morse taper.

To be honest the design started out as a quick prototype to test the new vac pump, I never expected to keep using it.

My original chuck was maybe 3 years old and although I have just replaced the chuck (different spindle thread now) I have reused the old beer line as it was still in reasonable shape. As long as you don't put a sharp bend in the beer line where it exits the tails stock it lasts a very long time in my experience.

Of course check from time to time and replace when showing signs of wear and long before failure. The beer line is a push fit (awkward and tight) into the bearings so is easy'ish to replace.

I have struck with the same design on my new lathe because it works so well and is easy to make and quick to take on and off. If it isn't broke don't fix it. Screw on chuck and push fit John Guest pipe coupler. The only downside is the chucks are a little ungainly to store with a length of beer line hanging out the end.

EDIT - just checked, the original chuck was made in June 2012 judging by my previous forum posts so a little over 2 years old.

BM

 

[Inspector]

Thanks for the quick reply BM. Makes sense for your circumstance and is a simple solution that doesn't require special adapters to mount on the end of the shaft.

Pete

 

[bogmonster]

Greg, I think on the new lathe I would have gone with a similar design as yours if starting from today and not having experience of how well the stationary beer line works. One thing to remember when you switch to a low volume, high pressure approach is that even small leaks can vastly reduce the holding force. This is far less of an issue with high flow rate shop vac style solutions. For example, if you use the spindle as part of the vacuum you need to ensure that there is minimal leaking at the chuck / spindle interface - probably easy to do with a gasket but just another consideration.

The bigger the pump you buy, the less it will be impacted by inevitable leaks either through the bowl or the rotary coupling or elsewhere. Having said that you still only need a small pump.

The Gast pumps are some of the best and quietest, but speedy unless you can find a good second hand one. My wife's oxygen concentrator (she uses if for jewellery making, not breathing problems thankfully) died the other day and that has a Gast compressor / vac pump in it. Like an silly person I fixed all the hoses in the OxyCon and it is now working again, no Gast vac pump for me

BM

 

[gregmcateer]

Cheers, BM for the advice. I'll keep my eyes peeled for one, but no real urgency - apparently items inside the actual house take priority :? I know, weird ain't it?