by Harry Hopcroft, Tide Mill Institute

When the circular saw blade on display at this summer’s Georgetown Historical Society exhibit was closely examined, it was found to have an extra plate mounted in the center, and on only one side. The extra piece is severely rusted in place now, but was originally held on by a series of short machine screws installed through holes from the back side of the blade. It is about a third to half the diameter of the main part of the blade, and thicker at the spindle than at its edges. The main blade itself is about 1/8 inch thick, and the added piece is ½ inch thick at the spindle, then tapers to almost knife edge at the outside. The main blade also has very little “kerf”, which is the measure of the width of the cut. The kerf is created by bending the cutting teeth outward in an alternating pattern from one side to the other. That allows the blade kerf to be a tiny bit wider than the thickness of the blade, and helps prevent the saw from binding.

The sort of obvious answer was that the extra piece was there to stiffen the blade, but it also appeared that it would severely limit the depth of the cut available with this blade, so we wondered why it was added. We knew the blade came from the site of the Oliver Grist and Shingle mill on the west end of the dam in Georgetown Center, so presumed it had something to do with cutting shingles, not logs.

Continue reading “Saw Blade Mystery Resolved” →

Who would think the thoroughly researched story of a massive tidal power project in the 1930s at the U.S./Canada border would be the stuff of drama? Mark Borton’s new book, Moondoggle: Franklin Roosevelt and the Fight for Tidal-Electric Power at Passamaquoddy Bay, is no dry historical retelling of a complicated series of events. Instead, it’s a whodunit with a twisting plot for even casual readers to enjoy. The title of the last chapter encapsulates the mystery: “Who Killed Quoddy?”

But this book is much more than a light mystery meant to be read for entertainment. “This is the first full accounting of the dream to harness perpetual tidal power for the nation soon to become the most powerful in the world,” writes TMI president Deane Rykerson in his recent review of Moondoggle, available on the Island Institute website.

The setting might seem to make this a story about Maine, about the Town of Eastport, but it reaches much farther, especially in light of today’s search for renewable and non-polluting energy sources. As the reviewer comments:

“Will we find a way to work with the ocean for a green energy future? Here’s a compelling account of what can go wrong.“

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Moondoggle: Franklin Roosevelt and the Fight for Tidal-electric Power at Passamaquoddy Bay. By Mark C. Borton, Downeast Books (2023). Available in hardback or electronic book.

A corroded circular saw blade from the Oliver Grist & Shingle mill on the West Branch of Robinhood Cove, in Georgetown, Maine (US-ME-071 in the TMI database), has what appears to be a reinforcing hub. TMI’s Harry Hopcroft asks if anyone can provide information about this blade configuration. Was this center hub, apparently attached to the blade with bolts, common on circular saw blades, or was it a special construction for sawing shingles?

The blade is 34 inches in diameter and the center hub is 14 inches in diameter. The spindle hole is 2 inches. The main blade is only 1/8-inch thick, while the add-on hub is 1/2-inch thick at the spindle and tapers to nothing at its edges.

If you can shed light on this type of blade construction, please comment (see link below) or send email to info@tidemillinstitute.org.

On its online media platform, POWERHOUSE, The National Hydropower Association has just published an article by TMI’s David Hoyle explaining how Tide Mill Institute promotes development and use of tidal energy. “How Tide Mill Institute Preserves and Promotes Tidal Energy” outlines how the organization, as part of its mission, promotes re-use of old tide mill sites and development of tidal energy sources.

TMI takes four approaches to fostering tidal energy:

• Advances appreciation of the American and international heritage of tide mill technology.
• Encourages research into the location and history of tide mill sites.
• Serves as a repository for tide mill data for students, scholars, engineers and the general public and to support and expand the community of these tide mill stakeholders.
• Promotes appropriate re-uses of old tide-mill sites and the development of the use of tides as an energy source.

The article includes examples of current TMI efforts to implement tidal power, including active membership in the National Hydropower Association.

Read the complete article in POWERHOUSE

Tide mill enthusiasts who may want to expand their mill interests beyond tide power to those powered by rivers and wind should consider attending the September annual conference being organized by The Society for the Preservation of Old Mills (SPOOM) in Auburn, N.Y. (30 miles west of Syracuse). SPOOM is a long-time ally of Tide Mill Institute in preserving and studying historic mill sites, and it has many members in common with TMI.

The conference, September 7-9, includes two days of mill tours. On this year’s agenda are Pure Functional Food, Birkett Mills, Farmer Ground Flour, Ward O’ Hara Museum, and New Hope Mills historic and modern facilities.

A video produced and shown to selected audiences earlier this year is now available on line via the Tide Mill Institute’s YouTube channel. Sponsored by the Tide Mill Institute and Kennebunk Savings, the one-hour video, “The Tide Mills of the York River,” explores the remains of several York, Maine, tide mills using aerial drone photography and interviews with historians. The video includes an explanation of how tide mills work by Bud Warren, co-founder of TMI.

The first tide mill was erected on the York River in the early 1600s when Fernando Gorges sent men to the area for the purpose of building grist mills and saw mills. Tide mills continued operating on or near that river until the late 1800s or early 1900s.