PDA

View Full Version : air supply for 1/4 die grinder



peterg
07-05-2009, 05:27 PM
Hi, I am a woodturner/woodworker not a machinist but I do some metal work
to support my wood stuff. Will a 1/4 inch air hose-25ft long support the die
grinder? Do I need to go to 3/8 inch hose? Will an inline lubricator work?
Is there any chance that the lube oil will contaminate the air line?
The same air line will be used for a spray gun.
Sorry for all of the questions; but I am on a fixed income and I want to get it right the first time.
Thank you for your help. Peter in south central NJ

Dave Smith
07-05-2009, 05:43 PM
die grinders require lots of volume of air I would use 3/8" hose and lube the grinder itself. lube in the line will ruin your paint jobs or use separate hoses. good luck

aboard_epsilon
07-05-2009, 05:46 PM
yes it will contaminate the airline ..you will not be able to use that airline again for spraying.

if using the die grinder continuously ..a 14cfm comp will just about keep up with it .

all the best.markj

Bill Pace
07-05-2009, 06:12 PM
One question you didnt ask, and its probably the most important -- will my air compressor drive it?

As said, a die grinder is an air hog---but, thats not to say that with some getting familiar with how to ration your use of it that you cant get a lot of use out of one, even with a smaller compressor (I've got 2 right angles & 3 inline, I LOVE that little tool!) However those little pancake compressors and the like arent really wort considering though.

Since you mentioned painting with the same hose (lube the tool itself, not the hose) then you must have a fair sized comp, as a spray gun likes a lot of air too, so you may be alright.

And yes, the 3/8" will be better choice. A quick squirt of one of the spray lubes - LPS, liquid wrench, etc - at the conx point is sufficient for quite a lengthy work session...

oldtiffie
07-05-2009, 07:27 PM
It must be different here in OZ.

First of all, I have a "service station" 1/4" X 30 ft close-coiled air hose that drives just about everything - mostly - including my air grinder (which I gave away), air-gun, impact wrench and even my (timber) framing and fixing guns and my 16mm stapler. I'm not into tear-ar$ing or breaking records. So no worries there. I have 3/8" hoses that I rarely use.

The in-line oiler is a "pressure-drop" hog as it has a considerable obstruction to air-flow and so will or may cause a considerable pressure and volume drop at the grinder. The in-line oiler should fitted to the inlet of the tool and then the air hose connected to the oiler. That way all oil (very little) goes to the tool and none to or in the line/hose.

Putting a drop or two of a good real air-tool oil in the air inlet on the tool/grinder at the start and end of work as well as every hour will more than suffice.

Air-tool systems would have to be the most energy inefficient tools in the shop - and they blow exhaust air and a lot of grindings all around the place - including in the air you breathe. I gave my air-grinder (a good one) away as it pretty well took a lot of my compressor output as well as a lot of compressor noise and energy.

Speed control on an air-driven grinder is difficult at best as the speed is either all or bugger all.

I bought a "Proxxon" electric die grinder from LMS and have never looked back.

I am often amazed at how many here are so concerned about grindings from surface and T&C grinders and yet they think nothing of using an air die-grinder (or any grinder - "Dremel"s included - in the vise or on the bench - right near the tools they have out in the open etc.

The air demand for the die-grinder is rated as being under load ie running - so the outlet pressure at the compressor regulator should be at least 10psi greater than required a the die-grinder to allow for air-pressure loss across/along the air hose.

A 3/8" bore air line IS better than a 1/4" one as it has better air-flow characteristics - but it is heavy and a PITA sometimes. I'd stick with the standard 1/4" line unless there are compelling reasons to use or go to 3/8".

Use the grinder - any portable grinder/s or sanders - outside of the shop and down-wind (lee side) of any wind or breeze as some of those grindings stay air-borne for quite a while.

Pretty much as for a wood-working shop.

radkins
07-05-2009, 08:46 PM
Air-tool systems would have to be the most energy inefficient tools in the shop -



And that's saying it mildly! With the air demand of something like an air die grinder a 3 HP compressor will not keep up with the thing, not for very long at a time anyway, so it ends up using over 3 HP to get a fraction of one HP from the grinder. For the amount of power consumed most air tools are simply wasteful!


I respectfully disagree about the hose size however because of the high volume requirements of an air die grinder a 3/8" vs 1/4" will make a very noticeable difference in performance. Of course depending on what is being done with the tool maximum performance may not be needed but for full speed and torque from the grinder that 3/8" hose will make a sizable difference.

stoneysstarters
07-05-2009, 09:38 PM
For my bench work I use a 1/4" coiled air line suspended from between the lights above the bench. To use my air die grinder for any length of time I have to pull a 3/8" line from outside the shop.

gnm109
07-05-2009, 10:01 PM
Air tools are inefficient as mentioned but I can't think of any replacement for them when fabricating and cutting metal. I don't even own an electric drill with a cord anymore. I use air tools all of the time. I oil them periodically.

If not air tools then what?

radkins
07-05-2009, 10:30 PM
Air tools are inefficient as mentioned but I can't think of any replacement for them when fabricating and cutting metal. I don't even own an electric drill with a cord anymore. I use air tools all of the time. I oil them periodically.

If not air tools then what?



You are certainly right and I never meant air tools should not be used, just that they are wasteful of resources. I have an electric die grinder that is just as fast as an air version and considerably more powerful while using a fraction of the electricity of the compressor powering the air tool, it is however also considerably larger! Air tools have a purpose that's for sure and I guess that, inefficient as they are, they still have their place. They also have the advantage of being immune to overheating under a heavy load and will not be damaged by stalling from overload, both conditions being destructive to an electric tool.

oldtiffie
07-06-2009, 04:58 AM
Air tools are inefficient as mentioned but I can't think of any replacement for them when fabricating and cutting metal. I don't even own an electric drill with a cord anymore. I use air tools all of the time. I oil them periodically.

If not air tools then what?

Er-r-r-r

These:
full speed adjustment and very good speed maintenance under load. Total indicated run-out (TDI) as per my test Dial Indicator (TDI) = 0.015mm (0.0006"):
http://i200.photobucket.com/albums/aa294/oldtiffie/Med_Speed_Spindles/Proxxon_small1.jpg

And lottsa grunt and heavy-duty use, with 0.01mm (0.0004") TIR, and with excellent speed maintenance under load, this one:
http://i200.photobucket.com/albums/aa294/oldtiffie/Med_Speed_Spindles/Bosch_HS_Grinder3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Med_Speed_Spindles/Bosch_HS_grinder1.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Med_Speed_Spindles/Bosch_HS_Grinder7.jpg

More ...............

oldtiffie
07-06-2009, 05:02 AM
.......................... more.

http://i200.photobucket.com/albums/aa294/oldtiffie/Med_Speed_Spindles/Bosch_HS_Grinder14.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Med_Speed_Spindles/Bosch_HS_Grinder10.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Med_Speed_Spindles/Bosch_HS_Grinder6.jpg

That should do for starters. All are German - with top-class German quality, durability and spares and support etc.

There's more if needs be.