DoAll DBW-1 Bandsaw-Blade Welder
Revision as of 21:39, 23 August 2012 by Djscholl (Updates for work progress)
This highly specialized welder is really only useful for one thing: repairing broken bandsaw blades. It is also called a buttwelder, because the technical name for the type of weld it makes in the blade is a butt weld.
- Don't try to repair bandsaw blades yet, and please don't plug in the power cord.
- Has anyone else ever repaired one of these old welders? Yes, someone rebuilt an entire 63-year-old DoAll Bandsaw, and rebuilt the welder as part of the project. Photos and written discussion are available on this thread in The Garage Journal. The URL is to page 5 of 26 pages, which is in the middle of the section that discusses the welder. The same author has made over a dozen videos of this project. They are available in the YouTube channel for APmachinist. Blade Welder Parts Repair is #14 in the Bandsaw Rebuild video series, and is one of several videos that discuss the welder. Note that the author's welder is model 1A, which is more recent than our model 1, and features different electrical adjustments, among other differences.
- Can bandsaw blades made with newer technologies (1950 or later) be repaired with this welder? Yes, if the annealing instructions from the manual for a newer model, e.g., the DBW-15, are followed.
- Continue evaluation and repairs
- Disassembly and cleaning is finished.
- Status of electrical testing/repairs
- New light socket and bulb are installed and work at 220V.
- Grinder motor runs quietly, appears OK, grinder switch works OK.
- An electrical schematic diagram has been drawn and most of the wiring has been replaced.
- New insulators have been cut from 0.016 DMD sheet (Dacron-Mylar-Dacron from a motor shop, to replace the original waxed cardboard)
- Transformer wiring completed. Weld switch, heat switch, anneal switch, all transformer taps, appear to function OK. With 243VAC on the primary, the open secondary voltages are as follows:
- Anneal: 0.93 VAC
- Etching: 1.65 VAC
- Less: 3.00 VAC
- LessLess: 3.27 VAC
- More: 3.52 VAC
- MoreMore: 3.80 VAC
- These open-secondary voltages are higher than the nominal values listed in the manual, apparently because the nominal primary is 220VAC and our primary is 243VAC. For this reason, it is likely that the Less and LessLess heat switch settings will make better welds in our shop.
- A new knob has been fitted to the force adjustment.
- Replacement grinding wheel is installed. It needed more clearance inside the housing, and we were able to use the wheel to grind its own clearance.
- The moving jaw moves freely and has been aligned parallel to the fixed jaw.
- Steve H. has made new plastic tips for two of the adjustment screws, and both have been installed.
- Reassembly and rewiring have been completed.
- The movable jaw travel limits have been set.
- The rough adjustment of the weld stop switch has been made.
- Ready for welding trials
- Optimize weld stop switch adjustment
- Optimize heat switch setting
- Document force settings for different blade widths
- Box is needed to cover the parts behind the front panel
- Long-term location with 220V 1PH 30A power is needed