Questions about a Grandma Bear

[Frankferter]

From what I can tell, I have a Grandma Bear, pre 1980. This manual is what I used to decide this: https://www.manualslib.com/manual/1006796/Fisher-Stoves-Grandma-Bear-Iii.html?page=13#manual
It's not exactly this, but close.

We bought the house and the previous owner put it in, but I'm not sure that what he did to the inside is correct.

I have a few questions:

- The outside seal, where the doors fit in, have a gasket. I've assumed that was needed so I've replaced it. Is it true these stoves don't need it? (BTW, I've tried it without and the doors don't shut quite correctly and snug, but maybe there is another way to make this work?)
- There are two levels of bricks on the walls right now. The first level is as shown in the manual above. Then there is a second level on top of that. Then he put in a "roof" on top of that with fire-retardant boards. Is the second level and roof needed at all? The manual doesn't show either of those.
- The latch on the right side now won't cinch the door tight. It looks like the iron piece inside that the handle grabs onto has been bent over time. What is the best way to bend it back to it's original shape or is there another option?

Thank you!

 

[coaly]

The second course of brick was optional starting in 1977. It was added to raise the firebox temperature for a cleaner burn, probably the same reason a previous owner added more to the top of yours. Fiberboard baffles didn’t exist back then. You want the heat to rise to the top and radiate into the area as well as heat the cooktop. (Unless you are looking at a baffle that the exhaust has to travel around to get out).

The solid cast iron doors did not use any gasket material. The channel iron welded to stove front is the door seal. The center of iron channel makes contact with the raised portion on the back of door. The edges of channel iron makes contact with the back of door. This creates 3 points of contact all the way around the opening. Considered air-tight as built. (the first double door stoves in ‘76 used round steel rod seal with a round edge cast into doors)

When hinge plate holes become worn, or hinge pins wear from no lubrication, doors can become loose enough for gasket material to fit in the groove of channel iron. There is normally no clearance for gasket, meaning the doors will not close fully with something between door and door seal. The only gasket material that should be used is flat gasket if necessary. When replacing any that was added, it is important to wire wheel all old gasket cement off door seal so it doesn’t build up any thickness. That will stop latch from tightening on the wedge.

The angle of left door handle is not movable. When latched, the right door handle should match the same angle. If not, heating the latch rod with a torch is how to adjust latch rod. Bending while hot allows the rod to be bent tighter to a 90* angle as they tend to straighten out when overtightened or door gasket is added. They bend easily cold with a big wrench or pipe, but will go back when heated, so they must be heated to adjust. A propane torch is enough to get it hot enough. I bend with a large adjustable wrench very easily.

Since your latch is loose, this should have been corrected first, door gasket removed and door seal wire wheel clean as well as the back of doors. Adjust latch, and see if gasket is necessary. It normally isn’t. They were built this way to alleviate the need for replacement of gasket material. So many others use gasketing that new owners think it is missing and mistakenly add it.

 

[coaly]

The manual you linked to is after 1980 with arched top doors. That model will have a UL Label on the rear shield, does not have angle iron corners that become legs. A picture of your stove would identify it quickly.

If it has flat top doors it is pre 1979 Series I.
If it has arched top doors they are Cathedral, and used on both UL Listed and old style unlisted models 1980 and after. Both were available in 1979 which is why a picture may be the best way. I can give you other information about it as well with good pics.

All manuals are here;

Fisher Stove Manuals (US)

Bear and Fireplace Series I & II ; Early Manual BEFORE UL testing; ( before 1978) https://www.hearth.com/images/uploads/Fisher_Manual.pdf Fireplace Series III ; UL listed double door stoves ( copyright 1980 Printed 5-80 ) https://www.hearth.com/images/uploads/fischermanual.pdf Fireplace...

www.hearth.com

 

[Frankferter]

Your posts were so crazy helpful. Thank you very much! I appreciate the time you took to answer. I'm in the middle of getting it all back up to where it should be and so far everything is going well. I'll report back when it is all complete.

 

[sparki365]

@coaly, I have two Grandma Bear stoves hat I recently acquired. One was made in 1976 and the other is either a 78 or 79. The later model is a top exhaust and the earlier model a rear exhaust.

The interesting thing I noticed is the earlier model has Grandma dimensions on the width and what looks to be a correct firebrick arrangement. It, however, is 3" smaller front to back than the later model. So, the firebox is +/- 21" deep on the top exhaust and 18"+/- on the rear.

Do you think this is due to a Is difference between top and rear exhaust models or an inconsistency in production?

Thank you

 

[coaly]

1977 Drawings call for a 24 wide X 21 deep box. Venting configuration did not change the box size.

I will have to measure my ‘76 Grandpa to see if it was made to the specs I have on the ‘77 drawings. I never confirmed if it was made to the specs that was later sent to fabricators.

I believe it was your state’s fabricator that made their own handles for many, instead of buying springs. They opted to make their own barrel shaped handles, or buy them cheaper than the springs from Fisher. Lots of them exist in your area.

 

[sparki365]

1977 Drawings call for a 24 wide X 21 deep box. Venting configuration did not change the box size.

I will have to measure my ‘76 Grandpa to see if it was made to the specs I have on the ‘77 drawings. I never confirmed if it was made to the specs that was later sent to fabricators.

I believe it was your state’s fabricator that made their own handles for many, instead of buying springs. They opted to make their own barrel shaped handles, or buy them cheaper than the springs from Fisher. Lots of them exist in your area.

Thank you for the reply. I will get pics with dimensions of the smaller Grandma and share them.

 

[sparki365]

@coaly, here are the pictures of the stoves in question. The left one is the larger of the two.

Left stove box dimension outside and inside:

Right stove box dimension outside and inside:

Viewing screens:

 

[coaly]

‘76 is correct.
Below is cut sheet sizes;


This is a condensed cutting size from drawings so welders did not have to access prints in office. Drawings give notes and details on a separate drawing for each part.

Top bends allow 1/2 inch for radius of bend;
Upper top 11 7/8 to bend 1/2” radius. Step 6 1/4 to bend 1/2” radius, 8 7/8 Lower top. This gives 6 inch rise from lower to upper top.

If the newer stove top bend measurement is as follows, your top depth is for a Grandpa, so it would be a Grandma width, Grandpa depth. Notice the legs are not tapered, possibly from another fabricator since they normally made them all the same, or a special built by a worker there eliminates that step for someone?

Grandpa bends;
11 7/8 upper top to bend 1/2” radius. Step 6 1/4 to bend 1/2” radius, 10 7/8 lower top. This gives 6 inch rise to upper top.

Notice the Grandpa top has the same bends with 2 inch longer lower top at front. 29 1/2 width compared to Grandma 25 1/2.

 

[sparki365]

Thank you Coaley!

After reading your post again, I will dig into all of the dimensions to confirm. The initial observation is the almost 3" size difference of the firebox front to back between the two Grandmas.

I will dig into the strange "Grandma-pa" this week to see where the curiosity lies.

John