Saturday, August 11, 2018

Refined Baldor 7 Inch Bench Grinder

I've really wanted a nice bench grinder since 2010, when I used the baldor in the high school shop. I bought one nearly two years ago, but didn't get to it until now. I put together a nice belt grinder with VFD, but a belt grinder is just not as refined. Grinding cutters on a quiet and stable bench grinder has to be one of the most relaxing activities.

The Baldor came pretty rough from the factory and I resolved to make it nice. The tool rests were crooked and wobbly, and the wheel flanges/bushings weren't very accurate. The shaft was pretty concentric through, so it was worth fixing. For accurate grinding of drills and cutters, a solid and flat tool rest is helpful. I set mine 1/2" below wheel centerline. I can put spacers beneath the item to be ground to accurately set a grind angle.

I made the rests of 1/2" mild steel using hacksaw and file, and the Taig lathe to mill the slot and drill the screw holes. I machined the bushings all on the Taig lathe.

I used the Oneway balancing kit to balance the wheels. It works alright; the balancing stand is not very sensitive but the flanges are nice and accurate.

You can see it running here.

I set up a fixture for sharpening a drill, and for the first time I split the point on a twist drill effectively. Sharpening drills freehand is a controversial topic because people have such wildly varying ideas of what a twist drill should be able to do.

I've had many US-made machine-sharpened drills which are sharpened worse than I could do by hand. Obviously, machines can do a much better job than I can do freehand too. You basically get what you pay for--a $25 twist drill is bound to be alright.

For accurate drilling in home shop, I like Chicago-Latrobe screw-machine length drills. They have a super crisp split point and their short length can actually take advantage of a rigid setup. They don't tend to make lobed hole during start unlike jobber-length bits (when used without guide clamped to surface).

Next challenge is grinding a brad-point bit for sheet metal :)

Longboard Wheel Truing Mandrel

Made this mandrel for a friend to help him turn the flat spots off longboard wheels.

The fixed bushing is held in place with a taper pin.

When I dropped it off at the skateboard shop, the guy there was interested in making a gang arrangement on a dedicated lathe to true up four skateboard wheels at a time. I doubt he'll actually go through with it, but I'll share it here if he does.

A conventional shearing cutter used for metals doesn't work for cutting the wheel, a slicing tool is needed to cut off a band from the outer surface. I didn't bother to grind a special tool, instead I just flipped a thread cutting tool upside-down to see if it worked. A dedicated cutter wouldn't be too hard to make and would do a lot better than this mess:

Wednesday, August 8, 2018

Crossbow Roller Nut

I got a crossbow kit from Alchem Inc. when I was about ten. I never finished a crossbow, but I hung onto the parts for... 14 years now. I finally sold them for peanuts to an excited SCA member.

As a token to my fifth-grade self who didn't have the tools or knowledge to make a decent roller nut, I made a blank to send with the rest of the kit:

I didn't have any metal adhesive, so the steel parts are just a tight interference fit with the aluminum body. I hope the recipient puts it to good use :)

Friday, August 3, 2018

Composite roping palm

My leather seaming palm has served me well. I don't know how I sewed heavy stuff before I had it, but I imagine there was a bit of blood and something to do with pliers. Paired with the needle it's such a capable and portable tool. A picture is worth a thousand words: pre-sewing-machine, this was the tool behind the needle as people sewed entire suits of sails. Sailmakers still use them to reinforce parts of sails. I use them to fix my clothes and make bags-

(photo by Shannon Gallagher)
Sails have changed a lot. Sailmaker's palms ought to have a chance at modern materials and production methods too.

I'm having a go. I started a few days ago, making different designs of foil, tape, and sheet steel. A sturdy palm that fits the user well is rare. My current plan is to distill three sizes of palms, that will accommodate the majority of hands.

These prototypes are kind of homely, but I want to be certain of the shape and general design before I clean out my wallet to have the first mold machined. They need to be comfortable, tough as heck, repairable, and easy on the eyes. I'm working with a friend to make the composite base, the rest will be up to me and maybe a machine shop.