Grandma Brass and Glass Baffle Question

[hoosier..jim]

we have a grandma bear in brown double brass doors with glass series three i think . eight inch chimney out the top. found paper work think it was made by l. p. d. inc. fisher stoves thorntown ind. been reading the forum and am interested in putting in a baffle, stove has angle irons welded on inside both sides looks to be 45 degrees angle. above 5 fire brick in back is 1 lone brick above the row of 5 attached with angle irons . i read on the forum a thread by fisher fired and your answer. was thinking of making 1 using 5/16x22 1/2x 10 cutting the 2x3 notches 0n each end . my question is the lone brick in back will interfere with plate contacting back wall. should i notch plate so it will make contact? also will the 10 inch dim. work to allow the smoke and gasses to go to upper chamber and on up chimney?

Since the Everything Fisher thread has so much hard to find information, I'll start a thread with detailed info on each model as I put it together.

Anyone needing information on their Grandma or Grandpa double door stove is likely to find it here. Please ask if you don't find what you need !

Grandma UL Unlisted pre 1980 with 2 square doors;

Width ; 25 1/2" across top plate.
Depth ; 28 1/4" overall with ash fender (shelf)
Height ; 30 1/2" rear, 24 1/2" front
Approx. weight 406 pounds
Logs to 20" across stove
Heats approx. 1500 s.f.
Requires 5 bricks across back, 4 sides
Flue size 8 inch top or rear
Door opening ; 17" wide X 10 1/2" high

Measurements from original 1977 prints, weight from ad; Dec. 1979

Grandpa UL Unlisted pre 1980 with 2 square doors;

Width ; 29 1/2" across top plate.
Depth ; 30 1/2" overall with ash fender (shelf)
Approx. weight 454 pounds
Logs to 24" across stove
Heats approx. 2000 s.f.
Requires 6 bricks across back, 4 sides
Flue size 8 inch top or rear
Door opening ; 22" wide X 11" high

Measurements from original 1977 prints, weight from ads; 1978

The first double door stoves were made in Oregon in 1976. Jake Jackson was a neighbor (his stove patent has his address very close to Bob) and he asked Bob to build him parts for an outdoor barbeque. After the project, he ended up selling Jake a license to build Fisher Stoves in Redmond OR, and loaned him $1000 for his first steel order. Jake later had a customer want a double door stove to view the fire, and brought the idea to Bob Fisher's shop. Bob wanted no part of more cast door patterns, and knew the stove wouldn't be as efficient as his 6 inch vented single door stoves. Public demand (and Bob's wife Carol) caused the need for a "Fireplace Model". Bob took a ride to Redmond and found Jake selling an adaptation of his stove with double doors. They agreed to terminate his license to build Fisher Stoves after Jake fulfilled his stove orders. This wasn't far from Springfield where they both lived, and Bobs "factory" was now in Eugene. So that's where the first ones were produced. Jake went on to build the Frontier Stove line and their friendship lasted until Jake's death many years later. Fisher called the new line the "Fireplace Series". These have an 8 inch outlet compared to the single door "Bear Series" 6 inch outlet stoves. Available in top or rear discharge, best for placing the rear outlet type on a hearth exiting up the existing flue.
The Grandpa Bear was the largest at the time, only one other Fisher model, the XL was ever made larger.Grandpa measures 29 1/2 inches across the top plate, with the box measuring 28" wide X 23" deep. Comfortable heating 2000 s.f. as suggested in Fisher literature, the stove is capable of even more.
The first stoves had stars on the doors, and a 76 in the largest star on the right door. Like all other Fisher Stoves with solid cast iron doors, they do not use gasket material for a door seal ! The first door hinge ears were not drilled completely through for the common 3/8 round head rivet used as a hinge pin. These had a pressed in pin pressed into the bottom of the door hinge ear, so the doors could be lifted off without loosing pins, since the idea of double doors was to be able to view the fire with the use of a fire screen attached to the front of the stove.
In July of 1977 a revision was made for adding a rear and bottom heat shield made of 20 Ga. Cold Rolled Steel. This was designated as a model II on the prints. A notation on the drawing states the shields are not required when installed on a hearth in front of a fireplace.
In 1979 a Roman Numeral III was added and the door style was available in the original square with flat top, OR with a new arched top style, called "Cathedral" that became the redesigned UL Listed stoves of 1980. An optional nickel plate door became available in the cathedral style in 1980.
Also for 1979 was a "Furniture Style" leg option shown below.
The III was later offered with Brass and Glass, and later the Model IV with larger glass was added..​

Attached Files:
Early 76 Grandpa, Pre 1980 Grandpa,
Metallic Brown Grandma III, Grandma IV (with larger glass)
View attachment 64924View attachment 64925View attachment 64926View attachment 64927

 

[coaly]

Welcome to the Forum,
That depends on the chimney.
With a piece of cardboard, you can make a template the size of the baffle plate. I'd notch it for the brick unless the brick is loose enough to raise and sit on top of it. Measure the opening across the top of plate (smoke space) that the exhaust has to travel through. This needs to be a minimum of 50.24 square inches. I wouldn't add the area the square corner cut outs create to the total square inch area with glass doors. Only for slowing the air wash purposes.
The original baffle if installed was probably 23 X 3 1/2. They had no control over what kind of chimney it would be connected to. With a good drafting insulated chimney, you can make it much larger and close the smoke space off to the minimum. (or same square inch area as pipe and chimney cross sectional diameter)

Series III will have glass opening as this;



Series IV will have glass opening as this;

 

[hoosier..jim]

I sure appreciate your help. This will save me time and money. When i get the baffle made installed and tested i will send results.
Thanks again hoosier..jim

 

[coaly]

Thanks Jim, I've got nothing but good reports on baffles. 5/16 won't bow or sag in a Grandma width stove. You have the perfect candidate for adding secondary combustion, and I've experimented with that size stove. (without cutting, drilling or modifying the stove itself in any way) So if you think you may want to try that, use 1/4" plate instead, so you can make another one just like it with space between them for an air flow channel. Long story, it's easier to preheat the secondary intake air with a baffle instead of tubes. The hottest part of the stove becomes the baffle, so instead of preheat tubes and chambers inside the stove, I made a hollow baffle work fine. Depends on what you want. I prefer a stove that will burn more less than premium wood, and be going after 8 hours. I leave my house for more than 8 hours at a time and can't rely on a two hour secondary burn to have a warm house when I get home. I don't have another automatic heat source to kick in. Maybe I don't know how to do it, maybe just hard headed. I drilled supposedly 95,000 BTU worth of air holes and the heat output wasn't as much as just a baffle. At least it can be used either way. (Don't know what you have, but it takes an insulated 6 inch well drafting chimney as well)

Here's a thread with video of a Grandma with baffle adjusted for the chimney and fuel. It's very easy to raise the baffle with shims to adjust the smoke space.

Post # 28
https://www.hearth.com/talk/threads/cant-seem-to-figure-out.119184/page-2#post-1617042