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Reply by AHuxley

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Posted on Powermatic PM1500 Worthiness?

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AHuxley

874 posts in 4167 days


#1 posted 10-15-2018 01:09 AM



The only way ceramic guides will not do the exact same thing with pitch or sap is if you run them with zero clearance and I don t think that is the way to do it….my PM1500 is not the only bandsaw I own. I have one with pads and they have to have some clearance, if not they will very quickly make their own. I don t find this a problem with sap or pitch, it can only rub so much onto the blade before you have zero clearance due to the pitch and it will then start to scrape it off. Bearings will definitely make more noise when the blade gets puked up.
If you are wearing out 5 sets of bearings to one set of pads the bearings are not adjusted properly. I believe it cannot do anything any good to leave it tensioned up for a month or so. I choose not to do that.

Edit: one thing I find good about pads…when they are new and still nice and flat they do “guide” the blade better, but they will quickly wear a taper and have more clearance closer to the cut of the blade {bearings, being round, already have way more “bell” or taper towards the cut}. This taper allows the blade to deflect, with bearings you cant do anything about it…but live with it. At least with pads I keep a fairly new unworn set just for any “special” cuts I might have to make and know I have minimal blade deflection.
One other thing worth mentioning…the PM1500 comes with a heavy chrome plated cylinder “fence” for re-sawing. It works pretty good when doing heavy cuts because you can turn the slab and keep the blade tracking straight for a better cut…the problem is accurately marking an often non-flat or straight slab so you have a good straight line to follow.

- msinc

The beauty of ceramic guides is they can indeed be run kissing the blade. The benefit from a standard rectilinear guide is the ability to quickly change them and adjust them. For my PM 141 saws I have guide blocks made from multiple materials and can quickly swap in the best one for the task. Ceramic, bearing bronze, phenolic, hardwood and steel are some of the materials I have used and each has blades and cuts they work best for.

The problem with pitch is the skateboard bearings will never scrape they will simply compress it more and more. Turners are the most likely to have issues with this as they cut lots of green blanks.

Bearing guides don’t wear out from the normal axial and radial stresses that kill the vast majority of bearings in the world they die from dust infiltration. What you have is a situation where the guide needs to be shielded instead of sealed since the rolling resistance needs to be very low for them to function correctly. If they are sealed well enough to last a long time in the environment they live in they will tend to drag and wear out the bearing surface that touches the blade which since they are an off the shelf solution is not hard enough for the task. If you want to see a proper implementation of bearing guides look at Euro guides or the thrust bearing on higher end Carter guides (as well as the other high end guides use on big old iron cast saws). The wear surfaces that touch the blade are hardened steel and designed for the task versus the very soft steel used on the outside of a standard bearing which was never designed for the task. They are simply the poorest choice of the various guide options, I am not suggesting they don’t work but there is a reason you only see them on Asian machines now and not American or European saws.

Single point resaw fences work for some people but it starts to leak over into the full fence, half fence, single point, free hand debate. The vast majority of my resawing is veneer so I tend to be very fence oriented. The rare time a fence is not the best for the job of “splitting” a board I just freehand it.

In the end don’t get me wrong I actually have a soft spot for the big PM saws they are very aesthetically pleasing to me and generally well thought out my only issue with them is their price point. At the sizes that match up (15” does not) they are price ABOVE the benchmark saws.


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