Low-Speed Mod for my PM3520B

I added a 150 ohm resistor to the ground-side of the speed control potentiometer. I had done some measurements and that was the right resistance to let the lathe run at its lowest speed (48 RPM on the low pulley) when the speed control is all the way down. It used to stop the motor.

When I needed to run the lathe really slow, it was tricky to find the spot with the speed knob.

I may someday want to be able to turn the motor off with the speed control again. If that is the case, I’ll get a switched potentiometer to replace the original one. Then I can turn it down all the way to get low speed, and just click the knob to switch it off.

Headstock Tool Rack

I made a rack to sit on the headstock and hold my chuck keys, allen wrenches, and a few other tools I want to have nearby.

It’s simple: A chunk of scrap wood, with a lip routed out to fit the headstock, and 3 rare-earth magnets to hold it on. Looking at the pictures, it appears I cut out for the headstock and glued on another piece for the top. Whatever works!

The magnets aren’t enough to hold up the weight of the chuck allen keys, but adding the lip over the top of the headstock does the trick.

I drilled holes for the wrenches and things so that the shorter ones are in the middle, and don’t interfere with the spindle handwheel.

Dust Collection

I discovered that 3″ PVC pipe couplers are the same size as 4″ dust collector hose.

I cut a length of 3″ pipe, added a coupler and am using that rather than the large hood I had been using.

I think the pipe collects sanding dust better. Also, since the pipe is longer than the hood is, the stand can be farther back and out of the way. I was always bumping it with the banjo and had to walk around the lathe to move it around.

I added a pipe clamp to the stand where the two vertical sections slide together for height adjustment, so it will stay at the correct height but can rotate. Now I can just swing the pipe out of the way without having to move the stand around.

Drilling Tenons

I make goblets, and use a very shallow (1/16″ to 1/8″) tenon to align the stem to the bowl and base.

To drill these tenons, I use a 1/4″ straight router bit. These make flat-bottomed holes, which is important when the hole is only 1/16″ deep. A regular twist drill makes a pointy hole, and a brad-point bit has a point that will go too deep (and through the bottom of the goblet’s base).

I drill these on the lathe, with a Jacobs chuck in the tailstock. The quill on my lathe (Powermatic 3520B) has 16 TPI (threads per inch) pitch. That means that one revolution of the handle will move the quill 1/16″. I use this fact to measure the hole depth – advance the quill till the bit just starts to cut, then one revolution more is 1/16″ deep. Two gives me 1/8″, or 1 1/2 turns would be 3/32″, etc.

Corian Bandsaw inserts

I needed some inserts for my “new” (1968) 20″ Rockwell bandsaw. I had some squares of Corian countertop material sitting around, and it was just right.

I turned the inserts to the correct size, being careful about the diameter and thickness so they would sit just right in the saw table.

After cutting a slot for the blade, I marked where the slot in the table was, and super-glued a tab there to keep the insert aligned.

The one insert with the round hole is for wet wood, to help the chips clear through the table and (hopefully) get to the dust collector.

Sanding Disk Storage

This is how I store sanding disks, in PVC pipe end caps.

They are in a drawer so they stay clean of chips and sawdust. And Velcro-up so I can pick them up one at a time using the mandrel on my sander.

I don’t rely on the PVC to align the disk on the mandrel. I haven’t had any problems aligning the disks by hand.

Fixed my Wolverine Vari-Grind Arm

I got a new spindle gouge, and discovered that it bumps on the huge “pocket” on the end of the Wolverine arm.

IMG_5087
bump

I’ve never really completely liked the huge V-pocket in that arm anyway.

I found a scrap of plastic (I think it’s Delrin, but it really doesn’t matter).  I sanded an angle on one end and used a countersink bit to drill a pocket.

IMG_5091

Screwed that to the back of the arm with sheet-metal screws.

IMG_5093

And now my gouges don’t bump the arm. Also, I think this pocket works much better than the original.

IMG_5089

One screw goes thru the tube, and I ground off the other one (the lower one in these photos) so it won’t interfere with the existing pocket. I don’t plan to use that pocket, but I do loan my grinder to the club’s symposium and having the “expected” setup is probably useful for demonstrators.

Wolverine makes that pocket huge like that so you can drop the butt end of a tool handle in there.  Same reason the square bar comes so excessively long (I cut about a foot off of mine).  All the Wolverine advertisements show skews and roughing gouges being sharpened like that.  I think it’s a terrible idea – way too easy to have a gouge dig into the wheel and cause alot of damage (to the operator, the grinder wheel, and the gouge). Also, every time you sharpen, the tool gets shorter, which changes that angle.  Just get a platform and make some angle-setting jigs.  Much safer and pretty easy.

Bowl Bottom Center Finder

I made a center finder thing to mark the center of a chucked piece.  I often have a bowl or hollow form that has a tenon for my chuck, but no center mark.   If I want to reverse mount it, like in a jam chuck or vacuum chuck, it’s really helpful to know where the center is.

IMG_4988.jpeg

This tool fits right down into the spindle threads, and I can tap the knob to mark the center.

I took a scrap piece of wood and carefully turned a cylinder to just match the threads.  I then drilled a hole to match some scrap rod I had laying around.  I sharpened the rod to a point and epoxied a knob onto the end.

IMG_4986.jpeg

 

Wood Turning by Dave Landers