Thursday, October 27, 2011

My Suppliers

I've gotten parts and material from several different vendors. This is where I'm keeping track of them.

Lonsdale & Holtzman Sales Inc - A Hydraulic supplier in Baltimore.
Surplus Center - A web based parts supplier. Good website, enormous selection.
Small Engine Suppliers - Web based engine supplier. Very knowledgable staff. Helped me more with my questions on Briggs and Stratton engines than the Briggs and Stratton itself did.
Access Metals - A metal supplier in Baltimore. Helpful and knowledgeable staff.
Monumental Supply - Access Metals sent me here to order weld in flanges.

Tuesday, October 25, 2011

Progress for Oct 17 - 21

I was probably 6 times faster in the shop this week. I worked exclusively on the Power Cube frame. I welded the rest of the bottom square and all of the top square. The height of the steel frame may be changing so the uprights that I have are probably shorter than optimal. That means that turning these squares into a cube needs to be put off. For now I've decided to move from working on the frame to working on the hydraulic tank. This will give me time to think about the frame dimensions while still making progress.

I ordered the engine on Saturday, which I'm excited to get. I'll get some material locally this week. After that I'll be ordering the rest of the parts from Surplus Center. I started diagramming the hydraulic plumbing (draft on right) in an attempt to ensure I fully understand the tank. I'm pretty proud of my progress, but the diagram and my understanding are both quite incomplete. I contacted Tom, who has been helping me with various Power Cube related things. Hopefully he can help me shore up my understanding. I'm also hoping the diagram can become a useful part of the Power Cube documentation.

Sunday, October 23, 2011

On Engines

It's surprising how difficult it can be to get good data. I want to buy the right engine for my Power Cube. It turns out that there are a lot of engines out there. I was talking to a classmate about OSE and my project, and he pointed out that the parking lot we were in probably had over a hundred different engines in it. I am not qualified select an engine on my own.

I looked at the Bill of Materials for the Power Cube and was happy to see that the engine was already selected. It was a Brigs and Stratton 28 hp engine. Model Number 49M777. I didn't have to decide which engine to use. Well, the supplier that I'll be buying from offers three 'types' of the 49M777 engine. I asked my supplier and apparently the different 'types' are interchangeable. One type has a different governor spring, one type has a different spark plug. I suppose that the third type has nothing special.

So after much hemming and hawing, I've purchased an engine and await its delivery. Pretty amazing to be able to buy an internal combustion engine from somewhere in America and have it sent strait to my door.

A technical note: I spoke with a rep at Briggs and Stratton, the engine warrantee is invalidated by shortening the engine shaft.

Briggs and Stratton: has terrible phone help; has a poor website for comparing engines or getting engine specs.

Saturday, October 15, 2011

Progress for Oct 10 - 15

This is a really fun process. I get to take my time and do it right. This week I laid down the first weld on the Power Cube (version IV). I also started making progress on ordering my engine (post forthcoming).

I'm building the Frame of the Power Cube first. The frame is made of 1/4" thick angle iron. Its dimension are 27" long by 29" wide by 24" high. I will be making the cube taller so I don't have to shorten the shaft of the engine. The OSE folk turned me on to that modification. I'm waiting on them to get a new height. Until I know how tall to make the cube, I can only build the top and bottom squares of angle iron.

Welding Arrangement
The angle iron was already cut to length, so I could start immediately. My professor helped me set up the welder. I did a few practice welds to get the settings right, and get back into it-- I haven't welded in about 5 years. Getting the material into a proper square took some work, but I managed.

I laid down a few Tack welds to hold it all in place and remeasured for squareness. One of the sides had fallen out of alignment so I ground off the weld and fixed it. Now it was time to lay down some real welds.


If you look at the picture labeled 'Tacked!', you'll notice a pretty big gap between the two edges. I'm not going to weld this joint until I add the piece of angle that gives the cube it's height. With a piece of angle blocking the gap it should be an easy weld.

It took quite a while to get set up and started, but I was finally rolling. The piece was tacked and square, and I was ready to weld! But it was time to clean up. I had a machining course to attend. So I have a half finished welding job to finish up next week.

Tuesday, October 11, 2011

Tracking Hours

Gary mentioned how it would be worth having a record of how many hours it took to complete my project. This was enough to spur me on to add it to my spreadsheet. Most of the time I spend won't actually be on the spreadsheet. I'm not going to record, research time, documentation time, or correspondence time. I also won't include time that I pay someone else to spend (many of my steel cuts are done by my supplier for example). What will be included is fabrication time. I'm a relatively untrained fabricator. This means I'm less efficient than many who would undertake this project. Still, for someone who has done some carpentry, a little welding and a lot of experimentation this may be a reasonable estimate.

In the end I think it will be of major value to the OSE project to have records like those that I'm collecting. To have lots of data points on the costs (material, time, energy) of a Power Cube would really strengthen the case for OSE based businesses. I'm happy to collect data for my little project and hope to see data for other projects. Another person tracking their costs would help me understand when my costs are reasonable and when I'm slow or my materials are expensive. This may help me (or others) save major money/time.

Anyone can ask for access to my records in case they want to look more closely, or in case they want to use them as a template for tracking their own costs.