Sunday, May 2, 2021

5 Ways to use PVC Pipe in your Gardening Projects

Here are several ways you can use PVC pipe in your garden:

1) Trellis for Tomatoes and Peppers

In a big enough yard, you can use PVC pipe to build really big frames. In this garden I once attended to I used some smaller diameter pipe to act as a stake to allow the longer and wider diameter pipe to stand upright. Once the structure is standing, some string or other method of tying plants up can be used to keep plants upright. Read more about it here.

Friday, April 30, 2021

Turntable Final Assembly

Now that all the main components of the turntable are done, let's put it together!  I had a few hangups in assembly because, well, my blueprints were a bunch of scrap pieces of paper in a folder collected over the course of 3-4 years, and stuff didn't line up.  Anyways, in no particular order, here it is.

First, I needed the driving belt.  I bought two of these because I was originally planning to make two turntables (though after realizing how much hard work it was, I'm settling for one).  This was a standard 3/8" V-belt and, as noted on the label, they are 38" long.  These belts were actually too wide for the pulley that came stocked on the motors, but I couldn't find anything smaller.

Next, the plug outlet box.  As much as I love my Technics 1200s, the one feature they don't have is removable RCA and power cables.  This was one feature I missed about my first cheap set of Stanton turntables, so I decided to replicate it.  This box was to be made from some aluminum sheet metal.  The piece was actually left over from my old bike basket mount, which explains the unnecessary preexisting holes.  I drilled new holes for the connectors, mounting holes, and rivets prior to bending.

Tuesday, April 27, 2021

Turntable Headshell Connector

One of the biggest challenges in this turntable build was attempting to recreate the headshell connector.  This part allows for quick and easy interchangeability of needle cartridges between turntables.  Otherwise, I would have to unscrew and disconnect the cartridge cables every time I wanted to remove it.  Wanting this turntable to be compatible with my other ones, which accept standard headshells, I figured I had no choice but to make this connector.

The challenge here was the amount of small and complex parts needing to be made; a threaded locking mechanism, a slotted body, and insulated piece to house four spring-loaded brass contact pins, and the pins themselves.  Then on top of this, figuring out how it will connect to the tonearm and wiring it.

My version did a fair job replicating it, but it took a lot of hard work, several failed attempts and a few design flaws.  Part of the reason for my shortcomings was the fact that I didn't want to disassemble my Technics to see how it worked.  I just did the best I could from the measurements I could get on the outside.

Here's a diagram of my headshell connector.  The biggest difference between mine and the Technics is a snap ring holding on the locknut.  This is because my tonearm is a larger, and having to match this larger diameter on the connector, I couldn't slide the locknut on through the back.  On the Technics, the locknut is secured by a shoulder on front of the connector body.

Friday, April 23, 2021

Turntable Tonearm Linkage

Now that the turntable base and platter have been completed, the next step was to machine the tonearm components.  This assembly consisted of several parts which, though I tried to simplify it, ended up being one of the most complex and time consuming parts of the project.

I decided early on that I wasn't going to attempt recreating this gimbal mechanism the Technics has.  My version also omits several features for simplicity.  Namely, the anti-skating function and tonearm lift.  I was originally going to make the clip for securing the tone arm, but never got around to it.  I did however include a height adjustment for leveling the tonearm with the platter, but a more crude version.  I also made mine with a straight tonearm instead of the S-shaped.

My version:

Here's a diagram of the tonearm linkage and how it connects into the turntable.  Note, I ended up not using the locknut in the final build (above photo) because the tonearm would've been too high.

Tuesday, April 20, 2021

Casting The Turntable Platter - Sweep Pattern Experiment

The next step for the turntable project was to make the platter.  This was the second of the two cast aluminum components to make, and unlike the Technics which is die cast, this too would be sand casted.  However, this time I chose a different molding method called "sweep casting" which is applicable to radially symmetric parts like this.  This was my first time trying this, and I had relatively favorable results.

The sweep pattern is basically a cross section of the part being casted, which is swept around a central axis to remove pre-rammed sand layer by layer.  Think of it like those center pivot irrigation systems, except instead of watering crops, we're removing sand to create a mold cavity.

This has the advantage of saving time since I didn't have to make an entire wooden replica of the turntable platter.  I began by transposing the final dimensions of the platter, plus shrinkage allowance, into a flat piece of plate.  Pardon the atrocious blueprints