The Alberti Disk Sander

$900.00

Alberti Hand Powered Disk Sanders were first developed for violin and bowmakers to facilitate the shaping and fitting of small precision parts of wood, metal, shell and plastic. These sanders are also great for sharpening and honing knives, plane blades, gouges and chisels. In our machine shop we use them for sharpening cutting tools and hand flat lapping of small parts.

This new model sander is large enough to easily finish cello figure board ends and other larger parts. The table is 4” deep and 12.5” wide and is equipped with a precision fence system. The table tilts down a full 60 degrees and up 10 degrees with a fine adjustment screw that works at all angles. The up tilt enables precision adjusting of violin and viola neck angles.

The sanders feature a magnetic spindle with 9″ interchangeable flat steel disks to accept pressure sensitive adhesive backed sanding and lapping media as well as rubber cushioned, hook faced disks to accept loop back sanding media.

Accessories are available for tool sharpening and for the precision machining and fitting of bow frog slides (You can fit a new slide in ten minutes!). The sander is provided with a bench top clamp and holes for bolt-down mounting. It is set up for right hand operation, but can you can use the second post clamping hole for left hand operation. When we have suitable lamps available again we will provide a lamp mounting post for the second hole.

The sander is shipped with four plain steel disks. Extra steel disks, honing disks and sandpaper discs can be ordered separately.

To Order Call 800-982-4464

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The blue aluminum-zirconia disks provided with our sanding machine are well suited to both wood and metal finishing. This material is somewhat harder and sharper than aluminum oxide but breaks down with use much like silicon carbide. The net effect is this paper retains its sharpness but becomes finer in grit as you use it. The paper will, at first, cut quite aggressively and then settle down to a finer more controlled cut. 400 grit will give a nearly polished finish on tool steel when broken in but, initially, it will leave fairly deep scratches so you should batch your sharpening if you are using new paper in order to break it in with rough grinding until it is suitable for finishing. For all the discs that we use for tool sharpening in our own shop, I run a stone over the sandpaper to knock off the high pieces of grit before we use them. This eliminates any deep scratching and the discs will still have a long life, but with less noticeable change in the coarseness of the grit. The fiber honing wheel will quickly produce a near mirror finish when it follows a broken in 400 grit.

When mounting the PSA discs to the steel disks, we have found that applying some light oil or wax to the surface and wiping it off so very little remains can give enough adhesion of the PSA discs, but make them much easier to remove. Unless you apply too much oil or wax and prevent them from sticking at all. Please look for more information from us as we all get more experience with doing this, and share what you learn by emailing john@windstoneeditions.com.

Extra steel disks will allow you to rotate your grits through as they become effectively finer with use.

If you rough grind your tool at 5° or so less than you want your finished edge you will find it takes very little work with the finer grits to get a perfect edge. Remember that it is only the last quarter millimeter that needs to be scratch free. On good quality steel the honing wheel will remove your grinding burr even if only used on one side of the edge.

With practice of where to apply finger pressure to the blade and which direction to grind you will be able to get a truly flat surface on the backs of your plane blades, flat knives, and chisels.

When using the honing wheel you can eliminate dusting of the compound by very slightly wetting the wheel with kerosene or another very light oil. You will get a slightly less polished finish but not have to worry about the dust. A little kerosene on a paper towel wiped across the wheel is all it takes.

Warning: as with all grinding and sanding, many metals, plastics, woods and polishing compounds contain toxic material and you should take appropriate measures to avoid inhalation of dust.

This looks like a lot of steps when written out, but with practice the whole procedure shouldn’t take more than ten minutes. Try it with some pieces of popsicle sticks so you can get the feel of what you need to watch out for and how bold to be as you approach the final cut. Taking the slide in and out of the chuck will not affect accuracy at all if you don’t mischuck it, so don’t be afraid to check it often for width. When sanding the faces (front and back) of the slide, a combination of orientation of the slide and finger pressure will give you complete control of the thickness and any taper that needs to be sanded into the back of the slide.
frogslide instructions 1 1. Measure depth of slide dovetail in frog with the end of caliper. Check it in the four corners and the middle of slide.
2. Sand the wooden backing on pearl slide to conform to frog by checking with calipers and leaving the thickness slightly greater than frog slide depth.
frogslide instructions 3 3. Use the 1, 2, 3 block to set the miter fence square with the sanding wheel and check it twice as it must be perfectly square.
frogslide instructions 4 4. Lay the slide chuck on the table and set the top and bottom straight with each other.
frogslide instructions 5 5. Chuck the slide with wooden protrusion to the left and pearl up. Sand with chuck against fence to true the edge of slide and create the first dovetail.
frogslide instructions 6 6. Loosen top of chuck and place frog on measuring jaws with frog pointing to left. Tighten the top of chuck and slide off the frog.
frogslide instructions 7 7. Reverse the slide and sand the other edge straight. Adjust micrometer screw to just touch table and sand off a little more.
frogslide instructions 8 8. Measure in center of jaws to get width of slide.
frogslide instructions 9 9. Remove slide from chuck and measure width in center of slide.
frogslide instructions 10 10. Put slide back in chuck the same as you just had it chucked and, using the micrometer dial which moves 1mm per revolution (.1mm per number), sand off the difference of frog and slide dimensions.
11. Sand pearl side of slide to final thickness.