Blum planes are a radical departure from standard wood and metal planes. They combine the ease of adjustment of metal planes with the lightweight and tactile feel of wooden planes. And they solve the problem that both wood and metal planes share–the need to grind an oftentimes thick iron and while doing so grind it straight (or slightly cambered ), square, at the proper angle and all the while making sure not to burn the iron. The following is a list of the Advantages and Novel Features :
• Each plane comes with its’ own easy to use sharpening jig.
• The thin blades never need grinding.
• Plane is fully adjustable- no tools required
• No separate chipbreaker. The chipbreaker is integrated on the frog.
• No separate lateral adjuster required.
• No widening of the mouth as the sole is worn down from truing.
• Full handgrip without interference on the smooth planes.
• A scraper frog is available.
• Can be ordered with a cambered frog installed in the plane.
How does it work?
At first glance, you may wonder, where is the blade? That is a legitimate question, because it is not constructed like any prior plane. Look at the pictures below to see the construction details and the frog.
The thin blade is sandwiched between a massive frog which is 3/4″ thick at the bottom and a back-up iron which is 5/32″ thick. The leading edge of the frog thus becomes the chipbreaker and guides the shavings up and into the throat. The reverse angle of the frog matches the angle at the front of the throat, so the old problem of the throat widening as the sole is worn down from truing is no longer an issue. In fact, you can take 3/8″ off the sole and the opening will still be the same! The frog is adjusted for blade depth and lateral projection with the two adjusting nuts at the top of the plane. By being situated at the outer sides of the frog, adjusting depth also controls lateral adjustment so no separate lateral adjuster is required. There is no backlash in these adjusting screws whatsoever, so this is a very fast and precise process.
The large brass knob tightens the frog lock bolt which is captured in a T-slot in the back of the frog. This knob should be loosened slightly before adjustments are made and then re-tightened afterwards.
The mouth opening can be closed up by simply inserting a small shim behind the frog from the bottom of the plane. A thin piece of card like from a matchbook or similar works well. This is rarely necessary though, as tearout can easily be controlled by adjusting the chipbreak gap without even having to move any adjustments or remove the frog or blade.
Due to the unique frog design of our planes and the thin blades, it is possible to camber the bottom of the frog and back-up iron and leave the blades honed straight across. We put an approximate .002″ curve on the frog bottom, and then the blade is bent to this curve with the back-up iron. This is much easier and more consistant than honing a camber each time you sharpen.
All of our bench planes can be made into scraper planes by swapping out a plane frog for a scraper plane frog. This takes about 2 minutes. You then have all the adjustments of a bench plane. Filing and honing of the scraper blades is done with our fixed angle jig. See our Scraper planes page for more details.