Cooling while cutting

[BobL]

I have a old WW table saw that I have been using to cut small pieces of metal with 1.6 and 1 mm kerf (x 125 mm diam) metal cutting wheels. It's been a real improvement over waving an angle grinder in the direction of a piece of metal especially using the traditional features of a table saw like a fence and mitre slide. The other factor is this saw runs at 2800 rpm which means cooler cutting than the 10,000+ rpm cutting of an angle grinder. My question is about adding cooling to such a set up.

if I don't want to "blue steel", I have used the "Jake temperature sensor method" of placing a finger or two about 10 - 15 from the side of the cutting point and when it gets too hot I remove the metal and cool it in some water. The slowest part of the process is that one has to stop and start cutting, and moving the metal in and out of the cut does not give as smooth a cut as would be possible by leaving the metal on the saw for the whole cut.

Recently I have been using a spray bottle to cool the metal and this has been excellent. For example I can make a 1mm kerf cut thru 100 long x 6 mm thick tool steel in a couple of minutes, pausing about every 5 - 10 mm to spray water onto the cut.

What I was considering next was adding a small constant water stream to the saw in the same manner as a brick saw. I was thinking of a bottle of water with a hose and a fine nozzle to direct water directly onto the cut.

I can well understand why using water near an angle grinder is not a good idea but given the motor on my table saw is some 45 cm away from the table and the cutting wheel flicks the water in the opposite direction and down the dust chute are there any other reasons why one should not do this. For example, are metal cutting discs affected by being used in a constant water stream? Are some discs better than others.

[glock40sw]

G'day.
Why not outlay the readies and get a TCT steel cutting saw blade?
Set it up in the TC and saw away. No coolant required. Clean cut and cold to the touch. Irwin make them a nd they are available at Bunnies. I got one in a $49 GMC drop saw. Regularly cut solid 50x50mm steel bar with no problems. Blade costs about $100 But can be resharpened by the saw sharpener people.

[BobL]

Thanks for the info Glock.

I have seen those metal cutting TCT blades but the teeth from one of these blades would sometimes be bigger than what I am cutting/shaping? About half of what I do is fine stuff that makes use of the 1mm kerf, like cutting out and shaping small WW cutting blades, cutting/shaping small bits of brass etc which means I get sometimes my fingers close to the wheel. Blades with teeth I keep my bits well away from.

In a real metal shop some of what I do would be done with a small instrument amkers mill or lathe which we have at work and I do use occasionally, it's just a lot more convenient to have something at home. I still might get one of those TCT baldes for the bigger stuff.

[BobL]

Thought you might like to see my new continuous water cooling set up on my metal cutting table saw.

The usual blade used is a 125 mm 1.6mm kerf. Sometimes I use the 1.0 mm kerf. Have used an 200 mm cut off wheel as well but motor a bit underpowered for such a size wheel and can cut almost as fast and much cooler with the 125 mm blade.

The water tank attaches to a drip point on the saw guard via a bit of drip line hose and a small inline tap and it means I can make a continuous cut and adjust the water flow rate to the thickness of the metal and degree of cooling needed. Water runs down the saw dust chute drains to garden outside the shed

This is a very, very useful tool.

[jmk89]

Bob

Very neat solution. Now all I need to do is work out how to fit a cut-off wheel to my 235mm circular saw mounted in my Triton Workcentre!!!

Jeremy

PS B4 anyone responds, I am not going to try that, so don't worry.

[BobL]

Bob

Very neat solution. Now all I need to do is work out how to fit a cut-off wheel to my 235mm circular saw mounted in my Triton Workcentre!!!

Jeremy

PS B4 anyone responds, I am not going to try that, so don't worry.

Err , , , just in case someone does try this, no water cooling for you my friend - your saw motor is WAY too close for comfort.

BTW The recommend face plate sizes to use with these thin kerf blades is 1/3 the diameter of the blade - so a 125 mm diam blade shoulde be used with at least 40 mm diam face plates. You also need very snug fitting arbour/adapters and face plates as they are so thin they are liable to slip off and then go out of round very quickly.

Even though they are amazingly flexible, definitely NO sideways pushing/grinding. I have gone through maybe 25 of these blades (with numerous jams in the first few) in the last year but none have broken up on me yet.

In practice in my (1.5 HP) sawbench cuts about 2-3 x the speed of a brand new hacksaw blade in mild steel but of course with much less effort and a much smoother cut (ask Martrix). They cut almost as fast in tool steel. The fastest coolest cutting happens when a blade pressure is used such that the blade material is shedding itself quite significantly. This wears the blade fast but at $2 a piece they are not very expensive.

[jmk89]

Bob

Thanks for the additional info, which is very useful and interesting.

I agree that no-one should try this with a Triton - I was just being facetious (and taking the out of my own tendancy to try to work out ways to use my Triton to do things that perhaps were not in the maker's mind when it was designed!!!). I think comes into the same category as putting a cut-off wheet on the Model T's rear wheel hub!

Cheers

Jeremy

[Stringy]

"are metal cutting discs affected by being used in a constant water stream? Are some discs better than others".

The answer to this is Yes, when discs are left in the rain or damp environment they either tend to fall apart or when they heat up the moisture in them turns to steam and they explode. These discs are very thin and may not trap the water like thicker cutting and grinding discs, but still be careful and don't stand in the line of fire, definitely use a guard.

Most of the grinding and cutting disc accidents I have seen are from overspeed - someone has put a larger disc on an angle grinder or kickback.

[BobL]

"are metal cutting discs affected by being used in a constant water stream? Are some discs better than others".

The answer to this is Yes, when discs are left in the rain or damp environment they either tend to fall apart or when they heat up the moisture in them turns to steam and they explode. These discs are very thin and may not trap the water like thicker cutting and grinding discs, but still be careful and don't stand in the line of fire, definitely use a guard.

Most of the grinding and cutting disc accidents I have seen are from overspeed - someone has put a larger disc on an angle grinder or kickback.

Yes I did read these things on another forum and on the Norton Website which stated that metal cut off discs should be stored in a dry place, standing on edge (never laying down) or with stuff on top of them where they could develope a buckle. In terms of speed, my TS runs at 2800 rpm which is in itself a bit of a safety factor compared to angle grinder revs. My water cooler drops water on the metal and not on the disc although some does splash onto the disc but it seems to fling off the water as soon as hits them and they are never sitting in a pool of water. When I finish I run the motor for a minute or so and by then they appear bone dry. I have been using these discs with water cooling of the metal (mainly dipping the metal in water) for about 6 few months now and so far so good. Nevertheless, standing off to the side and using the TS guard, and full face sheild is SOP.