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My O'Keefe & Merritt Stove Restoration - 1

On Nov 2, 2013, I purchased an O'Keefe & Merritt gas stove (model # 500-2V) from a neighbor. She wanted to find a good home for it because she'd grown very fond of the stove. It's my very first gas stove, an appliance I'd been anxious to acquire for several decades. It also my first vintage appliance. I was barely familiar with the classic brand names. I happily moved my electric stove out of the kitchen, moved the O&M in. Thus began an unanticipated yet tremendous educational adventure for me; my first do-it-yourself antique stove restoration. Hats off to Parkie O'Keefe and Bob Merritt for making awesome ranges.


I'm trying to document nearly everything I saw, did, bought, etc., during this process. So it may take some time before this publication is complete. Check back every few weeks to see more descriptions and photos.


It's a 40" wide variety. The stove looked fine on the outside. A few enamel nicks and corroded chrome in spots but otherwise good. I loved its style, its lines; so welcoming and comforting, so wonderfully, blessedly non-stainless steel.

On the backguard were two time pieces, a clock and a timer, flanking two electric plugs and a stove-wide light. The backguard also had little chrome backguard trim panel. I decided to call this a 'tiara'.

It had four cooktop burners, and side-by-side oven/broiler; two simmer grates, two cracked spade grates, a slotted broiler top and an oven rack. A very basic model; clean and simple.

 

okeefe merritt stove

okeefe merritt stove

It had a "Grillevator" broiler on the left, oven on the right. And directions and tips - right on the doors! So vintage.

 

This is a photo of a fully restored O'Keefe & Merritt that's very similar to mine. It's been re-enameled, re-chromed, re-piped, de-rusted, cleaned, and fully functional.

O'Keefe & Merritt antique stoves are classics and still one of the best quality ranges ever made in the USA. Due to their quality O&M value appreciates with time. Try finding any humble appliance today that's designed to last for generations.

There was a bit of dark crud around and under the outside chrome trim, so I decided to whip out my pressure steamer and give it a good cleaning. Steaming along the top's edge seemed to loosen and flush out decades of accumulated crud (burnt grease and dirt).

Before hiring a plumber to hook it up to the kitchen gas line that had been capped for decades, I decided to do more cleaning and derusting. I had no idea the amount of crud just under the trim was nothing compared to what I was going to find just under the hood.

Since I couldn't find an online owner's manual, on my own I slowly began to learn how it was constructed so I could uncover and disassemble bit by bit.

These stoves were assembled by hand during manufacturing, so thankfully nearly everything was attached with basic screws/bolts. There were no bizarre screw heads that require unusual sets of drivers. No glued parts. An essential appliance that was extremely durable and easy to disassemble? How bizarre! :D

Taking photos every step of the disassemble would be the best way to properly reassemble.

It took me a while to find out how easy it was to explore just under the hood, since this was all new to me. Eventually I learned I simply had to lift the stove top lid from the front, kinda like the hood of a car.


Supplies and Tools (so far,'cause I ain't done yet):

  • Q-tips
  • Goof Off
  • household degreasers (various brands)
  • PB Blaster
  • wet/dry sandpaper
  • steel wool
  • paper towels
  • Scotch Brite heavy duty sponges
  • high temp epoxy adhesive
  • high temp spray paint
  • JB Weld epoxy
  • gaskets sheets
  • Rectorseal pipe thread sealant
  • Oately Great White pipe joint compound
  • gas line thread seal tape (yellow)
  • Hyheet graphite grease for gas valves
  • Blue Magic QuikSteel Extreme metal repair
  • phosphoric and muriatic acid
  • wood toothpicks
  • pipe cleaners
  • brass and zinc washers
  • aluminum solder & flux brazing kit

 

  • high power steamer
  • Dremel with abrasive buffs, grinder bits, polishing wheel, wire wheels
  • standard drill
  • medium and large blade screwdrivers
  • needlenose, round nose pliers
  • putty knife
  • cat food tins (emptied, cleaned)
  • shop wet-dry vac
  • small steel and brass brushes
  • wrenches
  • steel machine screws
  • buckets
  • mandrels
  • hammers
  • brazing torch
  • center punches
  • vice-grip pliers

Summary of purchased parts

  • Front control knob with attached chrome bezel
  • 2 piece Grillevator broiler pan
  • 2 spade (arrow) burner grates
  • 1 gas burner valve
  • 1 set gas burner valve parts
  • 1 oven/broiler valve
  • 4 burner head high temp gaskets
  • Robertshaw oven/broiler standing pilot
  • Robertshaw (BJWAZ) 4500-006 oven thermostat

Recommended websites for info

 

Recommended websites for parts

 

The Adventure Begins

Wiping away history under the hood

Condition just under the hood - not so good. Years of rust, accummulated old food bits and dust/ash. Eeewww. Amazing how dirty a space can get while it's covered.

I started by scraping gently with a putty knife, then wiping down the floor of the stove top with paper towels while testing several household degreasers (Grease Lightning, Grease Grizzly, Zep Industrial Purple). PB Blaster, Goof Off and lots of paper towels were indispensable. The kind of stuff I was removing would not rinse out of a sponge.

It took a while to find out with a little effort I could just pull the control knobs and bezels off the valves.

With the knobs, two crumb trays and the screws removed, I could easily remove the entire control panel. Removing it revealed many stove parts desperately in need of attention. There were dusty, corroded, rusty valves, a rusty manifold (the main gas pipe), gunk and rust inside and underneath the control panel, a badly rust-etched horizontal brace bar and hood support stick (steel rod that holds the hood open).

All the screws I removed were also pretty rusty. I scrubbed those with a wire brush and Scotch-Brite heavy duty sponge (green side), sorted them into various labeled cat food tins, and soaked them in PB Blaster.

Without disassembling much more, additional rust removal would be a bit harder. But I wasn't ready to get extreme on taking major things apart until I got more comfortable with Lucy (her new name).

Best items for metal oxidation removal (black rust, red rust, tarnish) depends on what's being oxidized and how much oxidation there is.

Mechanical tools like putty knives, wire brushes, steel wool, scrubbie sponges, and sandpaper are safe to use on most things because no chemicals are involved.

Chemical oxidation removers: what should be used depends on the metal.

With brass, the oxidation is actually a protective layer to inhibit further corrosion.

With steel and iron, oxidation is not beneficial. Red rust (iron oxide) will eventually devour the metal. There are lots of chemicals that can remove rust. Most acids will do a great job of removing rust. Although, because iron is so porous, certain very strong acids, like muriatic acid, tend to dig deep and break down the iron. Phosphoric acid turns iron oxide into iron phosphate, a very stable by product that can protect from further red rust.

My personal favorites when not in a hurry - distilled vinegar (1 day soak), citric acid (2 day soak), black strap molasses (1-2 week soak). toolmakingart.com - rust-removal

Recently, I discovered DMSO works, too.

before


after

Sandpaper, wire brushes and steel wool worked well to knock down most of the rust on the manifold and anything else I wasn't able to remove.

Afterwards, all formerly rusty surfaces I wiped with vaseline or PB Blaster to slow down further rusting.

Yes, I knew this was an appliance that spouted fire. I decided to take the risk. Turned out, everything was fine. The surfaces I applied the vaseline or PB Blaster didn't ignite or even smoke.

Initially I worked hard to remove rust from the cooktop valves while they were in place because I couldn't figure out how to remove the entire units. Some websites implied they were removable, but they neglected to say how. I settled for cleaning the surfaces I could see.


before


after

Stove's control panel:

  • about to get scrubbed down with a little soap and water
  • major rust patches on the inside
  • most of the rust sanded away and treated with vaseline



before

after

 

Stove grates and broiler tray

The stove did come with two simmer grates and two spade grates, but each spade grate had a crack in the ring.

Although there were many simmer grates for sale online, the spade grates were rare. Eventually I did find a pair via ebay. And they were nearly twice as heavy; the rings were twice as thick as the cracked ones that came with the stove. Nice.

I may solder the cracked set or send them off to be repaired and re-enameled.

The stove also came with a blue w white speckled broiler tray but it was missing the matching pan to catch the drips. So I ordered a replacement set from ebay. The replacement set had a chrome tray and a speckled blue drip pan.

Because, in this rare instance, I could easily create a matching set, I set aside the chrome tray! What was impressive is the replacement parts weren't flimsy, lightweight crap. They were good solid durable parts, as substantial as the originals.

Control knobs, chrome bezels, re-attaching control panel trim

The chrome bezels were fairly corroded. Even the copper layer underneath the chrome had corroded. The control knob springs practically disintegrated, they had rusted so badly. Toss.

I sanded off the corroded metal of the chrome rings with my Dremel with an abrasive buff.

A couple of the bakelite dials were cracked around the valve stem collars. I used JB Weld to repair the dial cracks.



Since the springs on all the knobs were now too rusty and brittle to do anything, the bezels had nothing to keep them in a fixed position.

I figured out a way to attach the bezels to the control panel using small machine screws and nuts and pieces of cat food can lids as washers.

 

 

The control panel ends had metal trim. There was a sizeable gap between the control panel ends and the main body. The strips decorated the panel and covered that gap. The strips also had micro-sized threaded screws and the smallest brass nuts I'd ever seen! Too small, in fact, because nuts were no longer large enough; they slipped through the gaps, leaving the trim poorly anchored.

I used more cat food lid pieces to help secure the trim.

The O'Keefe & Merritt banner was also loose due to corrosion. A little Kwik Weld secured it to the control panel.

 

The experts

The plumber came Nov 10, 2013 to hook up the stove to the kitchen's gas line. He was the first one to show me the process of lighting all the pilots, the proper burner flame characteristics and setting the oven and broiler safety switches to light those burners. The broiler wouldn't light at that time.

I left the pilot lights going, left one kitchen window open, closed the kitchen doors and left the room. A couple hours later when I returned and opened the kitchen door I got slammed by a very strong gas odor.

So I shut off main gas supply and called PG&E. They were quite responsive. A technician arrived a few hours later and started checking the stove for leaks with a gas leak detector. Most prominent leak sources - oven pilot light area and the oven thermostat itself.

Then he checked the stove's capabilities. He demonstrated how the burner flames should look, advised me to clear the burner holes of accummulated ash, especially since one of the burners took too long to light. And he adjusted the venturis (shutters) and valve gas flow nuts to get the proper mixture of air and gas to the burners. He detected the broiler's thermocouple was too weak to function so it would not open the gas line once heated.

OK. What's a thermocouple? How does it get weak? How can I stop the oven pilot light from leaking? Am I in over my head?

NO! I will learn, no matter how long it takes. It's worthwhile and kinda fun!

I loved the idea of keeping one of these tanks going. It was motivational to think a 60+ year old American appliance was still in good enough shape and could outlast anything I'd buy today. There was no planned self-destruct; no planned obsolescence coursing through this appliance's arteries.

This stove was designed to literally last for generations. How cool is that?

Next visitor was a local antique stove expert I paid to do a diagnostic. He confirmed the weak thermocouple and sold me a new one. He even hooked it up and the broiler lit up like a champ. He said the burner controls felt stiff and should be lubed. He gave me a bit of valve grease and advised to be very stingy when applying it.

Since I had already disassembled and reassembled one burner valve out of curiosity, I understood the reason for the advice - excessive grease can clog the valve openings, preventing the gas from flowing properly.

After the parade of experts, it was clear my major goal was to deal with all the gas leaks. I didn't know what was involved, other than to follow the PG&E technician's recommendation to replace the oven thermostat and investigate why the area around the oven pilot light leaked.

But I started considering all the other points where gas could leak. So I devised a basic gas management plan.

  • disassemble, lube and reassemble the valves
  • clear the main and simmer burners of built up ash and debris
  • replace the burner gaskets
  • clear the stove top pilot holes
  • replace the broiler pilot
  • replace the oven pilot
  • pinpoint the oven gas leak
  • check various connections for gas leaks

Stove burner valves

Mark, the vintage stove expert, stated the burner valves should be lubed. Of all the unfamiliar items in this stove that dealt with gas flow and possible leakage, the four stovetop burner valves seemed to easiest to tackle.

At first, I thought the valves would be easy to remove, but I could not find any screws to effect that task. After lots on online research, it became apparent the valves were screwed into the manifold. OK.

But the backend of each valve set deep inside the burner tube sets. The valves couldn't turn until the tubes were first removed. But how?

Until I figured that puzzle, the next best thing was to disassemble as much of the valves from the front.

Underneath the flat cover held in place by the front two slotted screws lay an odd shaped steel flat spring and a weird shaped brass cam that fit precisely around the valve stem.

There was a lot of fine particle debris at the base. I deduced later that the debris mainly consisted of brass scrapings, caused by the end of broken flat spring.

Though the flat spring was stationery, the brass cam would rotate with the stem. One end of the spring was missing its flared tip so the steel edge was scraping the brass cam, shaving off fine pieces each time the burner dial turned.

And guess what? You can't get replacement flat springs at Target or Home Depot! In fact, no one can just buy these itsy bitsy precision parts. One has to buy a whole valve.

View of flat spring and worn brass cam. All the steel valve springs and brass rings of my stove looked similar to this; offset worn brass rings and incomplete flat springs. Two of the four flat springs had broken tips

 

This photo shows a complete flat spring. That secondary kinda horseshoe shaped piece helps to keep the main spring in the correct position - I think.

I got this spring set from a replacement valve I ordered from Grapevine Sally on ebay. Now I know what a properly configured flat spring looks like.

Behind that front section is a special washer with a tab and behind that is a spring.

It's important to note that tab needs to hit the right edge of the valve when the stem is in the off position.

A freed burner valve! I lightly lubed it with the valve grease, put the valve back in and hand rotated it and pulled it out to check to see if any grease was blocking the openings. I cleared any excess and repeated those steps until the openings looked clear.

I serviced one valve at a time until all four had been lubed and checked. Each flat spring was in a different condition; only two still had those flared out ends. Each of those brass cams were unevenly worn down in different areas.

I work with brass for jewelry so one day I may make replacements. It's those little steel flat springs that could be a bear to reproduce. Gotta find the right type and gauge of steel.

I found a company nearby that makes custom springs Peninsula Spring, Corp. They're worth investigating one day. If I order a big batch, I could be in business. Lots of people with these stoves are looking for these little parts.

 

Later in my exploration, I discovered how to remove the entire burner valve unit. The burner tube sets (the big black tubes that run between the burner valves and the burner headers) can simply be lifted up and out! They're heavy, but removable. Once removed, entire valves can be unscrewed from the manifold.

Now, the backside of the burner valves. There are two gas openings per valve (larger one for the main burner, tiny one for the simmer burner).

The big black burner gas tubes have to be removed to view the valve orifices on the backend of the valves. They must also be removed before the valves can be unscrewed from the manifold.

The right front burner took too long to light and the simmer cap wouldn't light on its own. Since the other three burners worked fine, I deduced something was impacting the gas flow of just the one burner.

I decided to remove the valve from the manifold to see if it was possible to clear what might be restricting the gas flow.

You migh think removing a burner valve is straight forward. Maybe, right after the stove was built. It's a little different 60 years later.

The best adhoc tool I fould to twist the valves off/on is a washing machine spanner wrench. I assume there's a proper tool but I can't find one. Since the valve casing are brass, it's not good to use any hardened steel tool with jagged teeth like a vise-grip. Brass is too soft a metal.

So I covered the valve with a piece of leather so the spanner wouldn't damage the brass and twisted CCW to get the valve off.

Once I removed the end caps (orifices), it was easy to understand how those orifices controlled the gas flow. The points come close to fitting into their respective orifice holes. When the orifices are screwed to be as close as possible to the points - no gas flow.

The size of the orifice can determine the maximum BTU per gas type. Since propane is more potent than natural gas and butane is more potent than propane, to achieve the same BTU, the orifice size for propane needs to be smaller than for natural gas, and smaller still for butane.

I digress. Time to clean the orifices and the backend of the valves.

There was a small bit of debris inside the orifices after removing them from the valve. Since it only takes a small bit to clog those tiny openings, clearing them should help.

With Q-tips, Goof-Off and PB Blaster I removed as much of the brown and black debris as I could. With a 28-30 gauge brass wire, I cleared the tiny opening; then reassembled and reattached the valve.

First time I turned on the gas to that burner, the noise indicated too much gas was flowing out. So I tightened the two orifices to restrict the flow a bit more.

The cleaning worked! The burner lit up quickly.

I've a sneaky suspicion all the pipes/tubes that carry gas throughout this stove need the same cleaning, attention or replacing. #427 on my growing list of things to do.

Note: these are precision sized holes. They're sized only for natural gas. If converting to propane, these holes would be way too large.

 

 

Controlling burner gas flow

The burners (stovetop, oven, broiler) all have their own gas lines/tubes. After the gas passes through the valves, it must mix with air to properly burn. (side note: Natural gas needs much more oxygen than propane or butane. That's why converting a stove between natural gas and propane takes knowledge, skill, changing different parts.)

Regardless, it's important to control the air and gas mixture for proper combustion.

On my stove, each stovetop burner has four flow regulators:

  • one gas flow orifice for the burner head
  • one gas flow orifice for the simmer head
  • one pair of air shutters aka butterfly vents aka venturi panels aka wings.

I learned how to tweak the venturi and gas regulators to create the best flame profile possible.

The venturi (aka butterfly vent, air shutters, wings, etc.) are fairly easy to reposition to control the amount of air that mixes with the gas. For a few, I needed a flat head screwdriver to loosen the screw, then it was very easy to reposition the "wings".

Turning each hex nut of the gas orifices on my stove requires a 1/2" wrench; CCW moves the orifice closer to the point, thus reduces gas flow.

I used this page at Appliance411.com as a guide for proper flame characteristics. www.appliance411.com/faq/gas_range_flames

Later on I discovered the burner valves are known as Alltrol valves.

 

 

When clean, lubed and properly adjusted, it's especially nice to see the happy blue flames.

 

 

Alltrol burner valve cleaning

A couple of months after buying my first OKM, I purchased a second one. The condition of the second one was so poor that I considered it a parts stove. I planned to salvage any parts that were in good condition, like the burner valves, oven pilot, oven racks, clock faces. I thought about rechroming or re-enameling other parts, ones I didn't need, and selling them. I also planned on using the second stove as my guide in learning how to disassemble and reassemble without risk.

First items I wanted to extract were the burner valves. The second stove had six! The valves looked pretty bad on the outside, so a thorough cleaning was in order. Next - pilot valves.

After complete disassembly, I soaked them in Goof Off, then rinsed, then soaked them in a strong cleaner/degreaser and scrubbed them with a toothbrush. Then I sorted the valve pieces into two piles; the brass parts and the steel parts. The brass parts were soaked in a muriatic acid solution to remove the copper tarnish. The steel parts were soaked in phosphoric acid to remove the red rust.

Following that - a good rinsing. I let the pieces completely dry. I used pipe cleaners to snake through the channels between the conical valve space and the main and simmer orifices. There was a lot of gunk in those small channels.

I buffed them with a Dremel abrasive buff and/or rubber bonded abrasive wheels. Then it was time to lube. Gas valve grease on the stop cock, a light smear of light grease on everything else.

Ain't she purty?


The final restoration task for the Alltrol valves is to make replacement brass cams.

Huh?

Certain O&M Alltrol valve models have little brass cams inside. They fit snugly around the valve stem and rotate as the valve rotates. They seem to be responsible for that "click" one is supposed to hear when turning the control knob. As the cam rotates, the ends of the flat spring will ride the peaks and valleys of the cam and slap the brass cam (click). The click corresponds to specific flame settings between off and maximum flame. These clicks are referenced in the O&M gas range owner's manual.

Worn ones look like this >>>

There's a little steel flat spring that holds the brass cam. Over time after much turning of the valve, the steel spring wears down the brass cam. Sometimes the steel spring breaks in a place that causes the cam to wear down faster.

I've decided to try to make replacement cams. Unfortunately, I have no idea what a brand new cam looks like. It will be a matter of guesswork and trial to find the right cam profile.

Wish me luck!

As far as the steel flat spring goes, at some point I plan to find a custom spring shop that could whip up a batch for me.

The air shutters <> butterfly vents <> venturi panels <> wings. I've probably missed a few more nicknames for these things. While the burner valves allow you to control the gas flow, the venturi panels control the flow of fresh air. On these vintage stoves, since they look like basic butterfly wings, they have acquired other names.

With the exception of rust, they're fairly indestructible. Extensive rust will cause pitting. I neutralized the rusting by soaking the panels and screws in phosphoric acid. After rinsing and drying, they were sanded with the rubber bonded abrasive wheels. I finished them with a light PB Blaster rub.

 

Having trouble with a burner that's very slow to light or not lighting without a match? The gas and air flow/pressure must be properly balanced for everything to work. Pressure too high or low can cause problems. Consider:

  • gas flow amount/pressure controlled by the burner head orifice
  • gas flow amount/pressure controlled by simmer orifice
  • air flow amount controlled by the venturi
  • flash tube between pilot and burner tube set vertical neck (could be clogged or not placed properly).

If you have the proper tools (wrench, screw driver) and a gas leak detector (your nose isn't enough) and a little patience, you could adjust the settings, etc. to restore proper function. It'll require repeated attempts at adjusting (up/down) air and gas flows (one at a time), then turning burner on, turning off, then waiting 3-5 minutes for the air in the tubes to clear.

Seek a professional gas stove technician if you're not prepared to do this.

 

 

 

Last update to this page: 3 Feb 2014. Send comments, questions or suggestions to Desiree McCrorey..