To Stellite tip or not to Stellite tip?
With a large proportion of U.K. saw millers already using stellite tipped wide bandsaw blades, most sawyers / mill operators should, if they have not already done so, be considering the advantages to be gained by using stellite tipped blades.
Stellite is a wear resistant material composed of 60% cobalt, 29% chrome, 10% tungsten & 1% carbon and has a hardness of 47-51 HRC. This compares with a swage set hardness of 41-43 HRC and a tungsten carbide hardness of 67-82 HRC.
From these figures it's clear that stellite has a relatively high hardness factor but isn't as brittle as tungsten carbide. It has traditionally proved to be ideally suited for cutting timbers that rapidly wear down the cutting edges of swage set blades.
The extra durability of stellite enables the blades to be run for longer periods between sharpening, in certain instances 16+ hours have regularly been achieved, although this is very dependent upon the condition of the headrig/machine. Therefore it is necessary for saw millers to experiment and instigate a planned saw blade change/maintenance policy.
Generally, stellite can be run for twice the time of a swage set blade, with the obvious cost savings in downtime and resharpening, although it should be noted that blades need re-tipping every 6-12 sharpenings, dependent upon the maximum/minimum cutting kerf needed to maintain a consistent accuracy of cut.
From research carried out, mainly in the U.S.A., it has been established that a swage set blade can be using 15% more power after 4 hours use, whilst a stellite tipped blade, at the same point, will only use 1.5% more energy than when first mounted after sharpening.
We have noted from our own experience;A stellite tipped blade can be ground/sharpened to higher tolerances. Therefore a stellite tipped blade produces a smoother board finish than that of a swage set blade.The cutting kerf of a stellite tipped blade can, if necessary, be maintained consistently smaller than that of a swage set blade. Therefore less timber is lost to saw dust.
Since the amount of metal removed from the width of the blade, during re-sharpening of a stellite tipped blade, is less than that of a swage set blade fewer new blades need to be purchased per year.
- Reduced downtime.
- Reduced energy costs.
- Better quality of cut.
- Increased yield.
- Longer sawblade life.
Stellite is the registered trade mark of the Deloro Stellite Company.