How to Replace The Gem Roller Organ Bellows Part Two

Installing The Feeder Bellows Hinge Cloth and Valves

Feeder Bellows Hinge Cloth

This is a continuation of my previous post about replacing the bellows of The Gem Roller Organ. At this point the all the bellows cloth has been removed and the wood surfaces have been sanded completely clean of previous debris.

To begin installing the feeder bellows cloth, start with the hinge cloth. The hinge cloth is cut about 1 1/2″ longer than the length of the gap (the width was about 1 3/8″). The extra material must be cut to create two tabs at each end in order to fold over the feeder bellows cloth after it’s installed (see image above). I used a piece of bellow cloth from a previous project to create the hinge, not the material from the repair kit I purchased. The repair kit cloth will work just as effectively.

Using a double-boiler I combined about two tablespoons of dry hide glue and water in a small jelly jar. Once the glue reached 160°F (I monitored the temperature with a candy thermometer in the water of the double-boiler) I went to work. A disposable craft brush was used to apply the glue both to the centered hinge gap in the wood and the area of the cloth that’s inside the gap. The hinge cloth was installed with the help of a butter knife to push the cloth to the bottom of the gap.

New leather valves were cut from the leather from the kit and installed with hide glue. Remember, only the ends of the valve leather are glued! Be sure to keep the leather tight against the wood, for an air tight seal, before moving onto something else.

I added a little surprise for someone to find in a hundred years when they’re replacing my bellows cloth. It’s a photo of Lana Wood  (Natalie’s sister) from a 1961 Playboy magazine. I made sure it was fastened good with spray mount.

The image to the right (above) is me adding shellac to the hinge cloth. As I mentioned in the previous post, shellac helps to seal up little leaks that most certainly will occur.

Installing the Feeder Bellows Cloth

Feeder Bellows Cloth

Installing the feeder bellows cloth is fairly straightforward. Use the cloth you removed as a template for cutting the new material or download the pattern I created from mine. I recommend making a template out of paper to test the fit before cutting the replacement cloth.

Working one small area at a time, I applied hide glue to both the edges of the bellows wood and the cloth. I used some push pins to hold things in place while I worked, and while the glue set. In the end I used many more pins that are in the image above. The possible leaks the pin holes create are minuscule compared the leaks they’re preventing. I used a butter knife (image above) to press the cloth against the platform wood.

One word of caution. There is a finish applied to the wood in the push rod hole on the platform (red rectangle above) where the bellows attach. The original bellows were not stuck in this area, and it was very hard to make the new cloth stick as well. I permanently attached a few tiny tacks, applied with needle nose pliers, through the cloth and into the wood to keep the bellows sealed in this area.

When the cloth is completely attached remember to glue, fold over and tack the little tabs from the hinge cloth (red circles above). Leave the pins in overnight to allow the glue to cure. Resist the temptation to “test” the bellows until you’re sure the glue is set. I also sealed all the seams with a few coats of shellac.

Installing the Reservoir Bellows Cloth

Replace the reservoir bellows cloth following the same technique used to replace the feeder bellows cloth. Start by installing the hinge cloth. The hinge cloth for the reservoir bellows does not have tabs that wrap around the sides like the feeder bellows do. Instead, the main reservoir bellows cloth has tabs wrapping around the hinge cloth. Use plenty of pins to keep the cloth in place until the glue is cured. Use a razor blade to trim any access cloth protruding over the top edge of the lid.

Assembling the Gem Roller Organ Cabinet and Push Rod

Gem Roller Organ Push Rod

Now would be a good time to inspect the reeds. With the reed block detached from the front of the cabinet gently blow on the reeds. It’s not a trumpet, you’re lips shouldn’t need to touch the block to sound each reed. I forgot to make certain all the reeds were in working order before assembling my Gem, and a few don’t sound. Reviewing some photos of my reeds, it is clear some are bent out of position. One day I’ll go back and adjust them.

Use bellows cloth, or I used black craft foam, to create a gasket for the front of the cabinet (photo above). Install the front of the cabinet and attach the mechanism. Then guide the wooden push rod from under the platform and attach it to the crank. Tighten the screw, then attach the other end of the push rod to the feeder bellows. With the push rod installed, attach the platform to the four sided base.

A note about the push rod. The original push rod on my organ withstood several attachments and detachments. During one assembly it broke (#1 in photo above). I crafted a new one out of random black walnut and it broke while being attached (#2). Next I tried a piece of Douglas fir (#3). It broke as well.

It was then I looked closely the wood grain of the original. The grain was tight and quartersawn, meaning the grain was parallel to the block (green check mark above). The red X in the image above shows bad wood grain for the push rod. The gran is bad because cracks occur with the grain.

A scrounged around my stockpile of wood scraps and found a suitable piece of black walnut. The resulting push rod (#4) installed with easy success.

Replacing the Valve Pads

Replacing the valve pads was an easy task. I used a dental hook to remove the old pads, they basically fell off. I used Q-Tips soaked with denatured alcohol to clean the metal surface. My patience was wearing thin so I decided to use CA glue (super glue) to fasten the new pads. Nothing stressful or unpredictable to report about the process.

The Gem Roller Organ Performance

With The Gem Roller Organ fully assembled (and somewhat adjusted) it was time for its first performance! I put on one of the cobs that shipped with the organ and started cranking. Strong and clear music filled the room. As I mentioned earlier, some of the reeds aren’t adjusted, so they sound weak or not at all. Regardless, the melody was clear and very familiar.

After sharing this video with my parents they immediately knew the name of the song, “Nearer, My God, to Thee”. My parents also knew this as the song the band played as the Titanic sunk.


I hope you’ve found my posts about The Gem Roller Organ helpful. I know it’s far from comprehensive, but it’s a lot more information than what’s on the internet. If you’d like me to post other specific information, or if you’ve found any errors in the text please let me know. I had a fun time restoring my Gem Roller Organ. If you decide to restore a Gem on your own, take your time, don’t rush or set any deadlines. It’s a slow process that’s best suited for deliberate and careful work.

How to Replace The Gem Roller Organ Bellows Part One

Repairing the bellows of the gem organ

The Gem Roller Organ

I’ve been enchanted by The Gem Roller Organ for many years. I’ve scoured the web for every nugget of information I could about this mechanical marvel and I’ve learned just about everything there is to know. The two things that fascinate me most about The Gem Roller Organ are:

1. The bellows create a vacuum to pull air through the reeds (as opposed to pushing pressurized air through reeds, whistles or pipes).

2. The drive mechanism not only rotates the cob, but slowly offsets to the left. This increases the duration of a tune to three rotations of the cob. When the tune is complete a spring loaded release mechanism pushes the cob to the right, which resets the cob to the start of the tune. It’s amazing how much is going on in such a small mechanism! (more on that at John Wolff’s Web Museum)

Loaded with everything I’ve learned about the Gem, it was time to get one of my own! I purchased mine on Ebay for a handsome fee, even though the listing clearly stated the unit didn’t “create much sound”.  Examining the images of the Ebay listing I knew the mechanism was complete and in undamaged condition.

It was clear, however, someone tried to repair the unit by gluing the sheepskin valves on the feeder bellows completely closed! Knowing full well that there was certainly an underlying problem that caused this repair, I suspected fixing the valves would not return the unit to its original glory. Long story short, the bellows cloth and valves needed to be replaced.

Things to Consider Before Starting a Restoration

Restoring my Gem Roller Organ required about twenty hours of effort using the CONCERT ROLLER ORGAN REPAIR KIT from Roller Organ Restorations for eighty dollars. This company will restore a Gem for as little as $255. The repair kit includes an instruction sheet that, personally, I found confusing and of little use. I say this because it is assumed the reader already understands the name and function of every part and there are no illustrations. If you aren’t comfortable with working with tiny parts, hot hide glue and tight spaces with awkward bits you may want to seek the help of a professional.

The cotton based bellows cloth included in the kit functions well, but looks like neoprene and nothing like the original cloth backed black rubber of the original. I prefer the aesthetics of the original cloth and there are other downsides to the kit’s cloth which I’ll explain later. However, it’s great that someone provides a quality kit to replace the bellows and pallet valve pads in one kit.

If you decide to replace the bellows I recommend carefully disassembling the unit, storing screws and small parts small labeled Ziploc bags and record the order in which the unit was dismantled. When all the parts are clean, the original bellows material is completely removed and the wood surfaces are sanded clean the unit should be assembled in reverse order.

Hide glue is the way to go when working with bellows cloth. If you’ve never worked with hide glue before, it can be intimidating at first. It’s not as complicated as it seems and I find hide glue much easier to use than any other suggested replacement adhesive. I purchased my hide glue from Tools For Working Wood. The site has a clear explanation of the various strengths, I use 315 gram strength. While your shopping for supplies I recommend picking up some shellac flakes as well. Dissolve the shellac flakes in denatured alcohol (not rubbing alcohol) and you’re good to go.

“Good to go where,” you ask? Shellac works well for sealing up any leaks that unavoidably occur between the bellows cloth and the wood it’s attached to. A few coats around the perimeter helps keep leaks to a minimum. Shellac is not mentioned in the Organ Repair Kit Instruction Sheet, and with good reason. Shellac discolors the cotton based material, so care must be used when applying shellac. The discoloration of the cloth on the feeder bellows (under the cabinet) doesn’t matter much because it’s hidden. The shellac needs to be applied to the reservoir bellows from inside the cabinet to prevent discoloring the outside of the fabric.

Opening the case of the Gem Roller Organ

Replacing the Bellows on The Gem Roller Organ

Opening the cabinet is fairly straightforward. The feeder bellows push rod is attached to the crankshaft by the springiness of the wood and locked into place with screw #1. Loosen screw #1 enough to gently release the push rod from the crankshaft. Well done! The hard part of opening the cabinet is complete.

Now remove screws #2 and #3 to detach the crankshaft bearing from the case.  The crankshaft assembly can be removed by gently guiding it out of the bearing in the rear of the mechanism. Remove screws #4-8 in no particular order. The front panel can now be removed by sliding it forward.

A Look Inside the Reservoir Bellows

Bellows Springs, Push Rod, Reed Block
We’re finally getting a view of things my internet searches failed to reveal! The top half of the image is the inside of the reservoir bellows. The springs hold the bellows open against the vacuum created by the feeder bellows below. When the vacuum compresses the reservoir too much the lid touches the relief valve push rod which opens a valve on the underside of the cabinet, temporarily allowing air into the reservoir to reduce the vacuum.

The lower half of the image shows the reed block attached to the front panel. The reed block can be detached and gently cleaned. To do so,  remove the two remaining screws on the front panel to the left and right of the palette valves. A word of caution: In my haste to attach the reed block after cleaning, I mistakenly attached it upside down.  The resulting music was not very good.

Remove The Gem Roller Organ Reservoir Bellows

Remove Reservoir Bellows Gem Roller Organ
Using a heat gun (top left) to remove the bellows cloth.

Notice the little tabs on the large, three-sided bellows cloth that wrap around to the front at the corners and cover the “hinge cloth” across the front of the unit. These tabs are important to include with the replacement cloth.

I started the process of removing the reservoir bellows cloth by gently poking, prodding and cutting at the tabs with and x-acto blade and small dental hook/pick. This process worked well where the glue was compromised. However, the bellows cloth was stuck extremely well on the corners and a few other areas. That’s when I got out the heat gun.

With the heat gun on a low setting the flow of hot air was swept side to side on the areas that were stuck solid. To my surprise just as the temperature of the wood got almost too hot to touch, the bellows cloth easily peeled away from the lid and cabinet.

Be careful with the heat gun. Too much heat will ruin the finish of the wood cabinet! A heat gun, after all, is a great tool for doing exactly that, removing paint and finish. Those uncomfortable using a heat gun should start with a hair dryer with low heat.

Remove the two valve leather strips as well.

Accessing the Feeder Bellows

Gem Organ Feeder Bellows

Accessing the feeder bellows of The Gem Roller Organ was something that had me stumped. After a brief study of the construction of the cabinet I believed the feeder bellows were simply glued to the underside of the platform. “Perhaps a sharp downward drop would knock the bellows loose?” was the general theme of my thinking.

This is NOT the reality, so please don’t try it! The bellows do not disconnect from the underside of the platform, the platform disconnects from the sides of the cabinet. The image above has four red circles highlighting the screws to be removed to accomplish this. I suppose these screws were invisible to me because the construction of the unit was not as I originally expected.

Removing the Feeder Bellows Cloth

Building on the experience you’ve gained by removing the reservoir bellows cloth, removing the feeder bellows cloth is mostly an easy task. Start by removing  the spring and the three tacks to remove the relief valve (already removed in image). Next remove the two screws on the wooden feeder bar and remove the bar (a little heat should loosen the glue.  Remove the eight feeder bellows tacks (four on each side), I used needle-nosed pliers for the task.

Removing the Feeder BellowsNotice the tacks are binding  down tabs connected to the hinge cloth. This tab configuration is opposite of the reservoir cloth. Remember, the tabs on the reservoir cloth cover the hinge cloth, the tabs on the feeder bellows stem from the hinge cloth and cover the side of each feeder bellows. This must be replicated with the replacement cloth.

I removed the bellows cloth using heat, x-acto blade and small dental hook/pick. The hinge cloth is the most problematic to remove. I ended up using a rotary tool with tiny diamond burrs like these. The hinge cloth and glue need to be completely removed down to the wood! It took me two hours to remove the hinge cloth down to the wood.

The two valve leather strips should be removed as well.

Make sure all of the old bellows cloth and glue is removed on all surfaces! I will admit I used this Sanding Disc Kit quite a bit to accomplish the task. Don’t be fooled, these little sanding discs are hungry little buggers! A careful and gentle touch is all that’s required, slow and steady wins the race. A little side note about the sanding discs, I use them all the time on countless things. I’ve owned the set for more than ten years and I still have most of the discs. They last forever before they need to be replaced.

My next post How to Replace The Gem Roller Organ Bellows Part Two coming soon. I will provide downloadable patterns for the replacement bellows cloth. And yes, I’ll share the experience of replacing the bellows cloth and reassembly. If I’m feeling ambitious a video performance will be included as well!