Oil CBN versus Water Miscible
Prepared by: John Eisenhut
My thoughts on oil / CBN versus old school vitrified wheels and soluble oil in water
Just for your information and to enlighten everyone on consumables and maintenance on these Iseli saw shop servicing equipment / grinding machines.
To date on our site we have had no issues other than a broken belt on a side grinder through human error.
Other sites are in the same boat no issues (No maintenance costs)
With Thode our machines age is now 5½ years old: Cost in maintenance to date is zero for all machines.
The wheels on these Iseli machines are 250 to 350 mm diameter wheels x 7 mm thick CBN wheels.
The cost: for the 350 mm wheel $2600 + gst, (I hear you gasp)
At this stage 20 /05 /2020 the Red Stag wheels on all machines are 5 years old and look very much like they will get another year or two out of them, at Thode we turn over 100s of saws per month our usage is phenomenally low so cost per month on the 2.5 years is $86 per month. Cost per month on 4.5 years $48 per month per machine
Red Stags machines are sharpening 6 saws per day per grinder.
Each grinder is grinding in 2 new blanks per week for tipping
Each grinder is grinding in 2 used saws per week after re- tipping
Preventative maintenanceThe Iseli grinders only have saw steel and stellite grindings dropping into the oil reservoirs, the saw steel residue is gathered up on a magnetic base, so the oil stays very clean and only circulates that clean oil.
ExampleVitrified wheels in a water oil soluble mix environment last around one to two weeks cost around $300 dollars each so the math tells me consumables in wheels alone fast become a high cost
Add to this dressing sticks star dressers or PCD dressers and the cost continues to rise.
If a CNC Grinder and this applies to the Iseli range as well, uses water soluble coolants and vitrified wheels the cost for 3 years in wheels alone will be around 13K per grinder, in 6 years 26K as opposed to $2600 for CBN wheels in oil
If the option is to run vitrified wheels with Water soluble coolants not only is the consumable price tag large, the grinder quickly ages and deteriorate badly as water and sandy grit gets pumped around the internals of the grinder, this mix can potentially get into and onto moving parts causing rapid wear
As stated this has a tendency to literally sand the moving parts away rapidly creating premature failures in bearings, slides and ways,
With this solution being pumped around the grinder the appearance deteriorates quickly
Maintenance bills become large very quickly and as stated the grinder’s appearance become old very quickly, your asset depreciates very quickly.
With the substantial investment by a company in new Saw shop machinery, and an expectations of a 10 to 15 year benefit is somewhat wishful thinking with this application.
With oil and CBN grinding wheels, you can expect your grinders to outlast water soluble machines, two to three times, along with minimal consumable and maintenance costs etc.