Volume 6, No. 12 - December, 2001

Membership Information:

Membership is open to all those interested in machining metal and tinkering with machines. The purpose of the club is to provide a forum for the exchanging of ideas and information. This includes, to a large degree, education in the art of machine tools and practices. There is a severe shortage of written information that a beginning hobbyist can use. This makes an organization such as this even more important.

Business Meeting:

Minutes are sent via email or regular mail to members.

Regular Meeting Minutes:

1:00 p.m., Collier Library, 6200 Pinemont, Houston, Texas; 30 members attended.

President Dennis Cranston asked for suggestions concerning possible uses of surplus funds.  He also announced a casting workshop scheduled for 1:00 p.m. Saturday, December 1, at the Houston Area Live Steamers site in Zube Park.

Dick Kostelnicek reported The club's website has a new domain name, www.HomeMetalShopClub.org. The cost of hosting the website is $120.00 per year.

A suggestion was made to update Modeltec and Village Press Publications with current club information.  Secretary Ed Gladkowski has notified Modeltec and will follow up with Village Press.

Presentation:

Show and Tell:

The ‘home made’ Sheet Metal Brake was presented at the November HMSC meeting. It is fabricated from hot rolled steel plate and angle that was picked up from a scrap bin at my friendly fabrication shop. The only purchased items were the ball knobs and the socket head cap screws. The unit is a good project for the milling machine, band saw (or torch and grinding) and drill press with the only welding being done at the crank assembly.

The unit has capacity to handle stock that is 24 inches wide. The operating handle is a ½ inch diameter, 5 inch long, section of stainless steel bar with a 1-3/8 inch plastic ball and wrench flats. The rod is screwed into the eccentric unit, one on each side, that is 2-3/8 inch in diameter and has a reduced section for the crank shaft. The crank section has an extension welded on and threaded for the revised ball connection. The self aligning ball was removed to provide a larger diameter shaft. The eccentrics, on each side of the unit, are connected by a 5/8 inch diameter shaft keyed to each end with the shaft running in a bronze bushing at each end. This keeps both sides in synch. They are adjusted to provide over center locking with the material being bent. The base is mounted on a pair of steel angle sections, 1/4 x 2 x 3 inch, that have the anchor bolt holes and a milled section to provide a stop and a parallel mounting surface. The upper blade is made from a ½ x 4½ x 24 inch section with a nominal 30 degree face end with a 1/16 inch flat on the end. A reinforcing section of bar stock , ½ x 2½ x 22-11/16 inch, is bolted to the upper blade with counter sunk socket head cap screws. The pivot end sections are made from 3/4 x 1½ x 5½ inch stock. The mounting bolts holes, for the fixed side of the pivot are slotted to provide adjustment of the upper blade for different thicknesses of material. The side sections are 3/4 x 1½ x 5½ inch long. The pivots are ½ inch socket head shoulder bolts. The main frame end sections are ½ x 4½ x 7 inch and are contoured on the pivot end to provide clearance for the operating handle. The folding blade is a section of ½ x 4½ x 25-5/16 inch with the handles bolted to the blade. The handles have a section of heat shrink material. The pivots on each end are set to have the center line parallel to the edge of the folding blade. The pivots are socket head shoulder bolts running in a needle bearing at each end. The bearings were salvaged from a scrapped airplane. I have thought about cutting some slots in the upper blade to allow the folding of pans, but the unit has served well with out that feature. If I was to rebuild the unit, I would make it with adjustable fingers, but that gets complicated for a casual use brake.

This unit has served me well for many years. I welcome any one wanting to build a similar unit come to my shop and give the unit a trial run and check dimensions or fabrication features.

Introduction: The design process for the burner was not very scientific and relied on work previously done by others. The burner that I build is a venturi style, or naturally aspirated, burner. Ed Gladkowski, HMSC member, uses a similar one in his foundry. My furnace is relatively small and does not require a lot of heat to bring the aluminum charge to melting temperature. As it turns out, the burner that I built, is more that adequate for the freon bottle foundry.

Construction Notes: The burner uses off-the-shelf parts that can be found at most local hardware stores.

• The barrel is a 10-in. long piece of 1-in. black pipe, threaded on one end. The unthreaded end of the barrel fits into the furnace tuyere, the horizontal hole tangent to the furnace cavity. The venturi, a 1½ x 1-in. pipe reducer, is screwed onto the threaded end of the barrel.

• The jet is made from a short 1/8-in. pipe nipple which has a #60 hole centered along its length and cross drilled through just one wall. It is mounted in a short 1¾-in. long piece of 1½-in. pipe that has holes cross drilled through both walls close to the unthreaded open end. The jet is held in place with collars that have been welded to the nipple. Finally, a threaded cap closes off one end of the jet nipple. A 1/4 x 1/8-in. reducer is threaded on the other end of the jet nipple, thereby, connecting the burner to the hose assembly. All threaded connections are sealed with Rector5 pipe dope. The 1½-in. barrel is then threaded into the venturi to complete the burner assembly.

• The hose assembly is comprised of a LP gas cutoff valve, 8-ft. of hose, 0-20 psi regulator, 0-30 psi gauge, and various fittings and unions. I placed the cutoff valve at the burner end of the hose. A quarter of a turn of the valve completely cuts off the gas. The regulator and gauge are connected to a propane tank. All of the connections are sealed with pipe dope.

Furnace Performance: The burner has proved to be an excellent fit for the furnace. The burner will light without a problem inside the furnace. When withdrawn from the tuyere, a barrel flare extension is required to reduce the velocity of the gas in order for the burner to stay lit. With the regulator set at 2.5 psi, a full crucible of aluminum will melt in less than 15 minutes. I should be able to use this burner in a larger furnace or generate more heat to melt bronze or brass by increasing the gas pressure.

In retrospect, I wouldn’t do anything different, except buy a cheaper regulator (I paid $40 for the Fisher Controls regulator), and add quick connect fittings on each end of the hose assembly.

Freon Bottle Foundry - Part 1
Freon Bottle Foundry - Part 3

The next meeting will be held on Saturday December, 8  2001 at the Collier Library 6200 Pinemont, Houston, TX at 1:00 pm. Bring along a work in progress. Visit Our Web Site HomeMetalShopClub.org