Cold Cut Saw Lessons

[cuslog]

i don’t use my abrasive cutoff saw often but sometimes the cut just stalls (doesn’t progress), seems like the blade is toast ,!almost dull which I don’t understand. From your description this is what I experience . What do u believe is the root cause ?


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I've always thought of it as "glazing" of the wheel. More than once, (out of frustration), I've raised the wheel and put it back into the cut with a bit of a "bang" and it seemed to break off a layer of the wheel and it started to cut again. Probably not one of the recommended procedures in the owners manual but it does seem to work sometimes.

 

[Sailor]

Very good conversation, thanks. I’ve been looking at replacing my abrasive cutoff and this discussion has been very helpful.

 

[CalgaryPT]

I've always thought of it as "glazing" of the wheel. More than once, (out of frustration), I've raised the wheel and put it back into the cut with a bit of a "bang" and it seemed to break off a layer of the wheel and it started to cut again. Probably not one of the recommended procedures in the owners manual but it does seem to work sometimes.

That's a really astute observation. It kind of hints at glazing (dulling of the cutting planes) or loading (where the particles bunch up between the abrasive). Almost like you are "dressing" (or in your case Power dressing ) your wheel.

In my first house decades ago I had a grinder the neighbour used to come over and use. He use to always give me the gears because I never dressed the wheel and the stock got too hot. He used to look at it and say I was "making glass."

I've since learned.

 

[cuslog]

Abrasive cutoff saws are probably my least favorite method of cutting metal - had one for years and always dis-liked the way I could smell and even taste the dust, sparks etc. that they threw up. Bandsaw is still my favorite.
Grinding wheels certainly do have their place though, I have a shop built tool & cutter grinder of sorts and yes, a freshly dressed wheel is like a freshly sharpened tool - you don't really notice them "going away" but you sure do notice a freshly dressed one.

 

[CalgaryPT]

...always dis-liked the way I could smell and even taste the dust, sparks etc. that they threw up.

Yeah, I get that.

Funny how personal this stuff can be. For me, I love the smell. It reminds me of when I was a child and we used to have the old Lionel model train engines. The carbon brushes gave off a unique smell and I am reminded of it ever time I use an abrasive.

 

[YYCHM]

@CalgaryPT : we machine stuff on the lathe etc provided the seas are not to bad - like throwing you about - and the ice breaking is not heavy enough to throw off your finish or tolerance. If necessary we make stuff happen as its needed - bombs or no bombs - LOL

For the most part if it is rough, no one is working on something with added danger of things flying about. The ship is always moving and deflecting so the lathe is very big with a short length - it is a 13 x 30 I think - we used to have a 15 x 72 and it was horrible to work on - typically 0.005 out of round in the slightest seas.

We can accomplish some pretty neat stuff - surprisingly - and lots of hand work - you get very adept with a grinder and files....

What kind of stuff would you have to make on the fly to keep the ship functional?

 

[Brent H]

Well, probably 60% of the equipment is obsolete or super long lead time so we would make small shafts, bushings, repairs to bearing housings, typically small items that will get something going again. This, however, has changed a lot over the past 30 years as the talent has died out....so sad. The ambition in the younger generations is typically not there, unless it involves some sort of sit around computer thing.

Liability has squashed fun big time. You always have to be aware of what they will blame you for if something fails and you didn't install parts made by a supposed "professional". The new stuff that we do get takes a lot of additional maintenance time as it is cheaply made and fails routinely - there are parts available and policies are to only use OEM so we suffer from the logistics side of things.

The older stuff that seems to last may get the odd part made to keep it in service but in some ways that is shooting ourselves in the foot because the machine doesn't get life cycled properly and becomes more of a liability.

We are always fixing vibration related issues and corrosion issues - making sounding pipe plugs, brackets for stabilizing things, welding up leaky pipes etc

We have had some neat adventures making custom lifting equipment to retrieve a plane that crashed through the ice, grappling arrangements to fish for lost buoys and moorings and custom tools for repairing the engines and gearboxes.

 

[Chicken lights]

Well, probably 60% of the equipment is obsolete or super long lead time so we would make small shafts, bushings, repairs to bearing housings, typically small items that will get something going again. This, however, has changed a lot over the past 30 years as the talent has died out....so sad. The ambition in the younger generations is typically not there, unless it involves some sort of sit around computer thing.

Liability has squashed fun big time. You always have to be aware of what they will blame you for if something fails and you didn't install parts made by a supposed "professional". The new stuff that we do get takes a lot of additional maintenance time as it is cheaply made and fails routinely - there are parts available and policies are to only use OEM so we suffer from the logistics side of things.

The older stuff that seems to last may get the odd part made to keep it in service but in some ways that is shooting ourselves in the foot because the machine doesn't get life cycled properly and becomes more of a liability.

We are always fixing vibration related issues and corrosion issues - making sounding pipe plugs, brackets for stabilizing things, welding up leaky pipes etc

We have had some neat adventures making custom lifting equipment to retrieve a plane that crashed through the ice, grappling arrangements to fish for lost buoys and moorings and custom tools for repairing the engines and gearboxes.

Have you had the chance to read Grey Seas Under by Farley Mowat? Fantastic book about a steam powered tug boat used as a salvage tug.
Anyway the point is those guys often had no choice but to make do and jerry rig stuff to do the job or just to make it home. I think you’d like reading it

 

[Janger]

i don’t use my abrasive cutoff saw often but sometimes the cut just stalls (doesn’t progress), seems like the blade is toast ,!almost dull which I don’t understand. From your description this is what I experience . What do u believe is the root cause ?


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I've noticed that too and thought it was some sort of work hardening or case hardening happening. @johnnielsen Have you got an explanation ?

 

[Janger]

Peter I think you have a "Dry cut saw". A cold cut saw is even slower - this one is 52 rpm. https://www.kmstools.com/king-industrial-12-slow-speed-cold-cut-saw-144824
And 4.5 HP! They cut through thick material pretty quick though and the swarf stays contained. Lots of money.

 

[johnnielsen]

I've noticed that too and thought it was some sort of work hardening or case hardening happening. @johnnielsen Have you got an explanation ?

I used to experience that alot. It is not the material (mild steel) work hardening but the cutting wheel glazing on the cutting edge and sides. Sometimes you could actually see the wheel had tapered sides. This happens more so when you don't feed the wheel into the workpiece aggressively or you attempt to start your cut in a wide flat profile. The only way to break through the glaze was a series of hard momentary whacks of the spinning wheel into the cut. I switched to the thinnest wheel I could find, preferably with a small wobble so the wheel cut a slightly wider kerf than the thickness of the blade. I had success at the time mostly with Norton abrasive cutoff wheels while flexovit were too well balanced and SAIT wheels were useless on small (14" and under) cut off machines though they worked ok on my 10hp X 20" cutoff machine.

 

[AlexJk]

Manuals can be confusing, so I am more than happy to read all your ideas and warnings. Now I have some insights why my work was taking a lifetime and why I was always stuck...

 

[JohnnyTK]

Well, probably 60% of the equipment is obsolete or super long lead time so we would make small shafts, bushings, repairs to bearing housings, typically small items that will get something going again. This, however, has changed a lot over the past 30 years as the talent has died out....so sad. The ambition in the younger generations is typically not there, unless it involves some sort of sit around computer thing.

Liability has squashed fun big time. You always have to be aware of what they will blame you for if something fails and you didn't install parts made by a supposed "professional". The new stuff that we do get takes a lot of additional maintenance time as it is cheaply made and fails routinely - there are parts available and policies are to only use OEM so we suffer from the logistics side of things.

The older stuff that seems to last may get the odd part made to keep it in service but in some ways that is shooting ourselves in the foot because the machine doesn't get life cycled properly and becomes more of a liability.

We are always fixing vibration related issues and corrosion issues - making sounding pipe plugs, brackets for stabilizing things, welding up leaky pipes etc

We have had some neat adventures making custom lifting equipment to retrieve a plane that crashed through the ice, grappling arrangements to fish for lost buoys and moorings and custom tools for repairing the engines and gearboxes.

Brent
This was just posted on what I assume is a Canadian Icebreaker & Buoy Tender.

 

[Brent H]

@JohnnyTK : you are correct - that is the “other” (LOL) ice breaker/buoy tender on the Lakes and now quite a bit more in Quebec. CCGS Griffon.