Author Archives: Jay

Ego 21″³ mower (LM2100SP) 2nd self propel motor failure & repair report

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No, this post isn’t an accidental duplicate of this post from last year. Yes, the self propel unit on my 21″ SP Ego lawn mower failed a second time. (This is 9 months after it was replaced under warranty from the first failure, which occurred around month 4 of ownership, so this failed self propel motor lasted twice as long as the first one.)

However,   I’m quite pleased with Ego’s warranty service compared to the last time when I had to take the mower to Home Depot’s service department (who kept it for 5 weeks).

This time when I called Ego’s customer support number, I only had a seven minute hold time before talking to a person, and the customer support representative said that they would send me out a new replacement mower, arriving in 5-10 business days. [I was instructed to remove the serial number sticker and take the defective mower back to home depot “for recycling”.]

I have read many accounts on Ego’s customer web forums of other self propel units failing, so they may have had a bad batch of mowers go out and are now being more pro-active about replacing them. Alternatively, maybe I’m getting a replacement mower shipped out quickly because this is the second issue I’ve had. Regardless, receiving a working replacement in 5-10 days is much better than taking 5 weeks for a repair.     I’m still going to have to push my mower to mow the lawn (and it’s a big lawn, so this is more exercise than I am looking for….) but at least I could use the defective mower as a push mower until the replacement arrived and didn’t have to hire a lawn service while it’s in the shop.

The new mower arrived 11 business days after my phone call (it would have been 10, except UPS had a delivery exception and delayed it over a weekend, which meant I had to push the old mower around one more time.

After using the new mower with its super quiet and silky smooth self propel, I can say that the self propel unit that home depot repaired/replaced had many signs of problems before it finally gave up the ghost. First, it was louder than the mower itself. Second, it didn’t have enough power to fully propel the mower up a slight incline. Third, every time the mower went into overdrive due to thick grass, the self propel would slow down. These issues were either there from the time I got the mower back from Home Depot, or they started and got worse so gradually that I hadn’t taken note of them, but after using the new mower, it became obvious that I should have known my self propel unit was not working the way it was supposed to. On the new mower the self propel has plenty of power to move up a grade at the same speed it moves on flat ground, it makes less noise than the blade mower, and it doesn’t slow down when the blade mower goes into “overdrive” cutting thick grass.

 

Update: Ego has started to produce updated 21″ SP models that have an updated self propel unit that matches that found in their dual battery (premium) mowers. Look for a picture of a phone on the box (see this video for details: https://www.youtube.com/watch?v=JtLkT5X4MQw )

2nd Update: My self propel unit failed a 3rd time, but this time Ego replaced the mower with one that has a different looking SP unit, so I’m hopefully I got the improved version!

Pokeball Decoration (MDF, Paint, Resin)

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I built this for my son. It was also a learning project for my new Maslow CNC Router (and using tinted casting resin to fill in pockets for a mixed-media project).

Videos of the process:
1 – How to design the digital file

2 – How to convert the SVG file into Gcode using the Makercam.com webapp

3 – Running the Maslow CNC Router and cutting out the part.

4 – Hand finishing, spray-paint and colored resin pouring to finish the piece.

 

You can download a zip file including the SVG and gcode (.nc) files here: pokeball_files

Degregation of EGO 7.5 AH lawnmower batteries over time

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I purchased a 21″ Self Propelled EGO lawnmower in April of 2017, and although the mower’s manufacture date code was listed as Sep 2016, the 7.5 AH battery (Original Battery) that HD gave me (shipped separately and lost for a week) had a date code of Dec 2014.

I just (July 2018) purchased a second brand new 7.5 AH battery that has a manufactured date code of May 2018 so that I can mow twice as long, and be charging one battery while mowing with the other.

To monitor the performance and lifespan of these (relatively expensive) batteries, I have been periodically testing their capacity by draining them to the same level (when the red light on the mower comes on) and then measuring how many watt/hrs it takes to fully recharge them using a Kill-a-watt meter. In this way, I can compare the original battery (both last year and now) to my new battery.

Here is my data:
Original Battery Aug 2017:   380 watt/hr to recharge
Original Battery July 2018:   330 watt/hr to recharge
New Battery, July 2018: 410 watt/hr to recharge.

I didn’t start keeping track of how much power it took to recharge the original battery until August of 2017, so I don’t know if it was at the 410 level when I originally received it or not. It’s calendar age from the date of manufacture was 2+ years old when I received it in April of 2017, and I estimate it probably lost 7% of its capacity before I started the measurements.

Conclusions:
The original battery has lost approximately 13% of it’s capacity over the last year from the point I started keeping track.
(380-330= 50 / 380 = 0.1315 )

Right now, my brand new battery is 19-20% “better” than my original battery (which is 3+ years old and has been in active use for 15 months).
(410 – 330 = 80 / 410 = 0.1951)

Said another way, my original battery still has 80% of the capacity of a “new” battery after 15 months of use and several years of storage before I purchased it.   (330 / 410 = 0.8048 )

Just for fun, here are two graphs of the data points I have for my original battery over time. The first one shows how the degradation appears to be mostly linear (at least over the last year) but looks scary, because OpenOffice cheated and auto-scaled the vertical axis to only include the data points.

 

This second graph represents the total capacity “under the line” is a better visual representation of reality, as only 13% of the original capacity was lost over this time period (20% when compared to a brand new battery, so the other 7% was likely lost in the years of storage before I received the original battery).

 

Update: See my next post for two years of usage data on my original battery, and 1 year on the new battery.

 

 

Maslow CNC “hanging router” review

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I have completed a few projects using my Maslow CNC “hanging router”. Although I’m not yet an expert on its use, I feel like I have enough experience for a general review. The bottom line is that it provides excellent value for the cost for a hobbyist, but will not replace a professional gantry style CNC router for professional use.

 

The source of the Maslow’s sub $500 cost is its unique motion system, which relies on gravity working against two variable length chains to position the router sled, which must slide on a flat work piece. Because you provide your own router, build the frame yourself, and cut out the final round sled using a temporary sled that you cut by hand, the electro-mechanical parts of the Maslow can ship in a large USPS priority mail box.

My Maslow is the 2nd generation that includes a ring for two chain carriages to roll along. The rolling chain carriages allow the two support chains to virtually “end” at the center of the sled where the router bit is positioned. This mostly eliminates negative effects of sled rotation and simplifies the kinematics of the machine. Earlier versions tried to model and account for the sled rotation with chains anchored off-center, or used a mechanical linkage system to achieve a similar effect. In my opinion, the ring and carriages is the best solution.

Continue reading →

UK Denford Micromill 2000 (February 2002 dispatch date) interior photos

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Steve is working on a UK (240 volt) Denford Micromill 2000 (February 2002 dispatch date). When referring to my four part series( 1, 2, 3, 4) about how I got mine working under CNC control, he sent me some photos of the inside of his unit which I am posting here with his permission just in case they can help others working with one of these units.

 

 

Maslow CNC setup

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After building the frame for my Maslow CNC machine, the rest of the setup was just a matter of assembling all of the pieces.   I used 1/4-20 “superstrut” nuts and 1/4-20 machine screws to mount the motor brackets. The slots in the brackets are almost, but not quite wide enough to let 1/4-20 screws go through them, so I had to drill them just slightly larger in the two spots I mounted the screws.

     

I made use of one of the four motor mounting holes to place an extra long (60mm) M4 screw holding a plastic idler that keeps the chain wrapped around the sprocket to avoid chain slips under tension.   I’m currently using a binder clip to keep the plastic idler from “crawling up” the screw and eventually letting the chain fall onto the screw.

I considered buying a shorter screw to keep the plastic idler from crawling up the screw, but if I ever want to manually adjust the chain position on the sprocket all I need to do is remove the binder clip and slip the plastic idler up out of the way, so I’m leaving it as-is for now.   I also paid Lowes an outrageous $5 for a set of two blue plastic end caps to make the end of my superstrut look nice.

 

 

You can see that I also hung the far end of the chain from the idler mounting screw, and adjustable tension is placed on the slack side of the chain with an idler sprocket weighted down with a few pounds of water. (So far I just put a few inches of water in each jug, and haven’t needed to add significant weight.)

I found that I could balance a small level directly on top of the chain and use the bubble to get a tooth of the sprocket aligned vertically within a 10th of a degree. (At least, there was a small but visible difference between the bubble between presses of the 0.1 deg button in the software…you’ll probably have to click the photos to zoom in before you can see it…)

 

I built a temporary sled out of a piece of plywood that was left over from covering a window during Hurricane Irma. Instead of bothering to countersink the heads of the provided brick mounting bolts, I just used deck screws to mount the temporary bricks.   I also was able to use the (too short) screws originally meant for the clear router base to mount the router to the plywood by abusing the heck out of a large countersink bit to REALLY countersink the screws so the short length was no longer an issue.

After calibrating the machine using the foam waste board, I used the temporary sled to cut a fancy round sled out of some MDF I had laying around. I don’t like the super fine sawdust that MDF generates, but it is more slick than regular plywood, which I figure is a good property for a router sled to have. (Plus, already had it laying around….)

 

 


 

 

Long Board & Sheet Storage + Maslow CNC Frame

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I built this rolling triangle shaped frame as a multi-purpose piece of shop furniture. It’s primary function will be as the frame for my maslow CNC router, which is why the front face is at a 15 degree angle and it has the 10′ unistrut beam at the top to mount the chain drive motors on.

But, if I’m going to have a frame to hold a 4’x8′ sheet in my garage, I wanted the back of the frame to serve a useful purpose, so I integrated sheet and board storage into the rolling frame. I can store multiple 4’x8′ sheets inside, along with many long boards in the top. It also stores various pieces of flat plastic and glass I’m saving for important future uses.   Continue reading →

Modular Raised Planting Bed

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I built a raised planting bed using deck rail planters.   This allows each planter to be moved to different locations within the bed, or to be removed from the bed entirely, allowing the bed to be   (relatively) easily moved.

I used pressure treated 2×4’s to make a simple ladder like frame, held up by four legs resting on 4×4 PT ground contact rated timbers. After painting the pressure treated 2x4s with exterior paint, I expect it to last a good long time.

In my effort to reduce daily chores, I’ve installed a drip irrigation system on a timer. Once the plants get established I hope that the drip irrigation system will soak enough of the containers so that I can stop misting the surface.

Cedar Closet System

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I built a closet system for our new closet.

Here is my first video, which shows how I installed the top shelf.

Here is the second video, which shows how to install the shelf cleats and hanging rods.

Here is the final video where I show off some extra work I did that probably wasn’t entirely necessary.

New charging inlet & Drive Away Protection

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So, this happened. A year and a half of meaning to get around to installing the drive away protection circuit later, I eventually drove away while the J1772 charger was plugged in, which yanked my inlet out of the truck, breaking the plastic air dam in the process. (Luckily, my EVSE wasn’t damaged.)   $150 later, I had a new J1772 inlet and air dam, and had to re-do all of my mounting work. I took this opportunity to re-work how the license plate mounted. Instead of tipping up (which shielded the inlet from view and made it hard to plug in without kneeling) I decided to make it slide to the side so that it would be easier to see and plug into the inlet. I used a 12″ stainless steel drawer slide (with self/soft closing features to keep it closed) for the motion.

Mounting the 15 amp RV inlet, button, and rotary switch was a simple matter of drilling the appropriately sized holes, but the J1772 inlet needed a custom mounting block that would match the interior contour of the air dam so that it could be recessed behind the license plate.

I assembled a stack of laser cut plywood into a block with the correct bolt pattern and cutout for the J1772 inlet, and then I sanded it down to match the interior contour of the air dam. I painted it black and mounted it to the inside of the air dam, and then screwed the inlet to the back of the block.

I also hooked up my drive away protection circuit. Here is a video of the finished system in operation.