Introduction: Short Bunn G1 Coffee Grinder Mod AKA:MiniBunn

Picture of Short Bunn G1 Coffee Grinder Mod  AKA:MiniBunn

MiniBunn Bunn G1 Mod

A “How-To” for chopping the Bunn G1 down to counter height

-lower the altitude and increase the attitude-

This mod uses the entire case. We leave the lid and footplate/drawer intactact. We will trim the back and two side plates, and then rivet them back together. The bag chute will be cut to accommodate the shorter distance to the footplate. The funnel/hopper will be removed due to decreased space. This will be replaced with a small funnel for "one pot at a time" grinding. If you want to continue using your funnel/hopper to grind and entire bag at once, do not cut the top section. Leave it in tact and consequently, save yourself time and energy.

Your first step should be to measure the desired height, and then decide where you want to take the inches from.

I removed enough of the case to allow the grinder to slide under my upper cabinet. For this reason I could not remove enough from the bottom section alone, I had to also cut the top. Aesthetics played a role in this to, as I thought it might look wonky with a huge rectangle cantilevered over a little cube.

No welding or advanced knowledge of metallurgy is required.

Tools required:

Level
Square / strait edge
Screw driver
Dremel with metal cutting wheels (wire reinforced)
Drill with 1/8 cobalt drill bit (made to drill in metal)
Hand Riveter $18 at hardware store
Steel rivets 1/8 by 1/8 (diameter is 1/8, grip is 1/8)
A bunch of small tupperware bowls or plastic cups and ziplocks for organizing parts
Painters tape or masking tape
Clamps
Beer

Step 1: Step 1: Remove Lid and Back Plate

Picture of Step 1: Remove Lid and Back Plate

-open and taste beer (lots of measuring and thinking involved in the beginning)

-remove plastic top/lid with screwdriver, and place screws in a bowl labeled “Lid”

-remove back plate screws and place in bowl labeled “back”

Now we gaze up the skirt of the G1. You will see that the motor is located into the top section, and basicaly nothing is sitting in the bottom section. (blue tape keeps threaded tabs in place) How low do you want to go? Getting rid of space from the bottom only is one way to go. If you are “catching” the grounds in a small container, measure to figure out the minimum clearance needed.

Step 2: Step 2: Oh Chute.

Picture of Step 2: Oh Chute.

Cutting off part of the chute can help too. I removed about 2 inches off mine so the back of the chute was level with the swing plate (the thing that swings).

Step 3: Step 3: Kill It.

Picture of Step 3: Kill It.

We will not be using the “bag kill switch” so don’t worry about keeping the slot in the chute or the switch itself. This is to protect the user who is not smart enough to keep a bag under the chute while grounds are flowing out.

Follow wires from switch and disconnect them.

Looking sleeker already.

Step 4: Step 4: Figurin'

Picture of Step 4: Figurin'

Now is a good time to taste the beer again because we are about to do some math.

How low does this need to be? Find your number. Then decide if you need to take those inches out of the bottom, or the top and bottom. The best option is only removing space from the bottom. Saves you headaches and time and keeps the entire funnel section intact. If you are like me and need to take this thing way down, then prepare to do some cutting.
Time for some math. My mod yielded a total height of 17 ¾ inches. I could have definitely gone shorter on the bottom compartment. I can slide a 7 inch tall container under the chute and keep the aesthetics I want.

On to deconstruction

Step 5: Step 5: Remove Motor

Picture of Step 5: Remove Motor

Grab your bowls and zip locks. Label where screws and parts come from and save yourself a headache later.

The lid and backplate should be removed at this point.

Removing the grinder/motor.

Remove the big shiny knob by loosening a screw on the side. (not pictured) Spin until you see it.
The knob will slide off. Resist the urge to get a big flat screwdriver and loosen the screw on the face of the knob. That is for adjusting the grind setting, not for removal.

After the knob is off, remove the 2 screws holding on the faceplate.

Turn the case around and look at the motors butt. All those wires that connect it to the bottom need be removed.

Unscrew the panel on the look at the wires. Now might be a good time to take a picture of what it looks like before we mess with it. Disconnect the 3 wires that can be removed by popping the red connector off the "tongue". Take a few extra pictures of which color wire goes to which spot. We will be yanking this heavy grinder/motor out shortly.

Almost free!
Remove the motor mounts. 4 bolts that go through washers and a rubber bumper. The motor should now be able to slide out the back. This thing is heavy. Better taste the beer again to make sure you are prepared.

Step 6: Step 6: Lets Take That Top Off..

Picture of Step 6: Lets Take That Top Off..

The case should be nice and light now that the motor is out.
Before we separate the two sections, we need to pop out the switch. Take a picture of the wires going into the switch so you can replace them later (I replaced the boring plastic rocker switch with a heavy duty metal one. I also relocated it under the top section to the right of the grind chute. More on that later) Disconnect the wires and pop the switch out.

To remove the top section from the bottom, 10 screws stand in our way. Remove them from the two ridges on each section that rest on each other. Place screws in a labeled container

We now have our top section free

Step 7: Step 7: Remove Footplate/Drawer

Picture of Step 7: Remove Footplate/Drawer

Now that the top is free we need to remove the footplate from the bottom section. The 2 ridges we just unscrewed that separate the motor section from the cavernous bottom section are sacred. SACRED. We do not want to mess with those ridges. When we remove material to shorten this beast, it will be from the bottom of the bottom section, or from the top of the top. But first the footplate..

Turn the bottom section upside down and remove the 4 bolts you see on the underside of the footplate

This will reveal a foam layer and a heavy duty platform

Step 8: Step 8: Remove Base Platform

Picture of Step 8: Remove Base Platform

The foamy base platform will remain intact, once we separate it from the case walls. This is a good time to protect the wires and control box by shoving everything inside a ziplock and taping it shut. I use some packing material and orange duct tape. Metal shavings will flying everywhere soon.

You might notice the pictures have taking a darker turn and boxes adorn the background. My wife decided my "project" did not need to take up the entire kitchen anymore, and I moved myself, my beer and my parts in the basement to continue.

To remove the black rivets, I used a grinding wheel or even a cutting wheel (reinforced wire one for safety) on my Dremel. Put on safety stuff and attack the lumps until the heads are removed. Once removed, the bottom section of the case will lift off revealing the rivet shafts on the base platform. Use the same Dremel to grind them off so the platform is smooth all the way around.

Step 9: Step 9: Cut Time.

Picture of Step 9: Cut Time.

By this time you have decided to either remove material from the bottom or the top and bottom.

You also know how much you are cutting off. If just removing material from the bottom, proceed and then skip the section about cutting the top.

Measure from the top ridge of the bottom section, down to your determined line. Draw a level line around the entire case. Use a straightedge and double check your measurements. The edge you cut will be "finished" depending on how you want the case to look. If you want to keep the Darth Vader black grinder look, then don't muck up this bottom edge with jagged wonky cuts. I wrapped my grinder in stainless steel panels to cover this up. More on that later. No pressure, just don't screw it up here. :-)

When you are feeling confident, taste the beer, don some safety equipment and fire up the dremel (or any spinning metal cutting device you favor)

Cut away.

Step 10: Step 10: Install Base Platform

Picture of Step 10: Install Base Platform

Congrats. You cut a handful of inches off the bottom case section.

You could balance all the sections on top of each other to get an idea of how it looks if you just put it back together and didn't cut the top.

After that, let's attach the base unless you determine you need to cut some more off the bottom section.

Attaching the base platform to the freshly cut walls of the bottom section.

Grab a drill, metal cutting bit (1/8" cobalt drill bit made to drill in metal) and some clamps. Set the platform on a level surface. Place the bottom section on top of the base platform so it wraps around it. Line up the black case and the silver base plate. We want the foam to hang down. Clamp the case to base. If you are awesome (or lucky) the top of the bottom section will be level. If not, now is the time to make it level before we rivet it onto the base. Position the bottom section on the base so that it is level and clamp the sides tight. How off is it? How sexy do you need this to be? You can remove some more of the sides, or just keep it clamped in a level position. Once satisfied, it is time to drill

Add extra clamps the sides of the case/platform. We don't want this to move now that it is level.

Measure the height of the platform. We want to drill a hole through the case, and have it centered on the side of the platform. These rivets transfer all the weight of the motor onto the foam and onto the footplate. Pretty important.

Once you have marked your holes (I just eyeballed it but feel free to mathematically space them out evenly. That reminds me, where is my beer?) it is time to drill.

To drill through metal, slow and steady is the key. Remember that piece we cut off the bottom? Practice on that.

Pressure the bit by leaning into it, and slowly, I mean slowly pull the trigger. Like, one or half a revolution per second. Super slow.

Now that you are an expert, drill your holes on the side. You will feel it "kerchunk" through the case, and take more time through the thicker baseplate. Go all the way through and into the foam. Next up. "We Can Do It!" Rosie the Riveter time.

Step 11: Step 11: I Like to Keep My Audience Riveted

Picture of Step 11: I Like to Keep My Audience Riveted

I am using a hand riveter I bought at H.D. along with 1/8 by 1/8 steel (not aluminum) rivets.

Have you used a riveter before? Remember the holes you made in the scrap metal practicing the metal hole drilling?

Let's rivet them together! Follow instructions on box which equate to "load rivet in riveter, place in hole. squeeze fully. Then squeeze again until it snaps off"

Once you feel confident riveting, stay focused and finish this project. I did not, and instead riveted everything in my house. It is like a manly "Bedazzler".

Rivet the holes on the case. Your base is now firmly and semi-permanently attached to case.

If you are not cutting any inches off the top, you are almost done! Skip the top cutting section and proceed to resizing the backplate.

Step 12: Step 12: a Little Off the Top

Picture of Step 12: a Little Off the Top

You don't want to cut this off unless you have to.

This is because you will lose the original funnel/hopper. With that comes a nice little lip that sits on the top of the case edge. On my setup, the original lid just plops on my cut edge, but I did lose that nice factory black lip that comes with the funnel.

On to cutting. The deepest you can cut is to just above the metal brace in the middle of the top section. Cutting the top flush with brace will not allow the lid to seat properly. Don't forget we are cutting a piece of the top off, not a piece from the bottom. Mark your lines. Measure twice and cut just like you did for the bottom.

Step 13: Step 13: Backside

Picture of Step 13: Backside

At this point, we need to cut the back panel to fit our new case and then reassemble.

It turns out that it is easier to attach the bottom and top sections first rather than using rulers and math. (math? how is this still the same beer?) Also attach the bottom footplate to the base as well.

Once assembled, mark on back plate where the new holes need to be drilled to line up with the existing (or should I say remaining tabs). This back plate is thicker steel than the case walls and is kind of a pain.

Once drilled, screw in the screws and make sure everything is nice and secure.

Now it is time to trim the backplate. Use a straightedge to mark a line level with the sides across the back plate.

Unscrew it, cut it (again, thicker steel so it is a pain) and get ready for assembly.

Step 14: Step 14: Assembley

Picture of Step 14: Assembley

Time to put it all back together.*

I picked up a roll of sticker backed foam from the plumbing section of H.D.

I went crazy and covered the entire inside of the case with it to help reduce noise.
If you did not cut the top section of your case, this foam will help if you also foam the underside of the funnel.

I cut my top, had to discard the funnel, and mine is pretty noisey mostly because there is not a good seal when the lid is shut.

Before you slide the motor in, if you cut the top section, you will need to bend out the two screw tabs first.

Slide the motor in, and re-bolt it to the bottom section. Then attach the faceplate, and bend the tabs back.

Attach the wires (refer to the pictures you took) to the motor. Screw on the backplate.

* I decided to upgrade to a different switch. I also wrapped the entire grinder in stainless steel, replaced the old detent plate and upgraded the sticker on the faceplate. If you want to use a different switch, do it before you replace the motor. I moved my switch so that it "aims down" and is located next to the grind chute. All these cosmetic mods will be covered in a different Instructable. This Instructable is only for shortening the Bunn G1.

Step 15: Step 15: Grind Some Coffee

Picture of Step 15: Grind Some Coffee

You did it!

You turned your powerful, but grossly oversized grocery store grinder into a sleek counter top unit.

You could leave it as it stands; a black panther, mean and svelte, ready to pounce.

Or you could wrap the sides in wood, ala GS3.

Or add stainless steel. I will cover the stainless steel panels in my next instructable for the Bunn G1.

Good luck and have fun

-Kurt

Comments

"rivets are like manly bedazzlers" hahahaha, so true!

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