Replacement Blades for DeWalt 25mm Tungsten-Carbide Snap-Off Shop/Utility Knife AKA Box Cutter


In the interest of never having to track down the exact replacement blades for my DEWALT 25mm Cartridge Blade Snap off Knife model # DWHT10250 with 25mm laser-deposited tungsten carbide (oOoOoOoh~) edge, please find below links to the 5 (DWHT11925) and 20 (DWHT11925F) packs of replacement 25mm snap-off blades.

Local hero AvE tears down and tears into the gimmicky tungsten-carbide coating which is typically used to make drill bits extra hard but is virtually useless at prolonging the longevity of a rough-and-tumble shop knife like this as its failure tends to stem from chipping of the blade edge which is not improved whatsoever by the additive.

It's not immediately clear how to reload one of these gadgets if you've not had to in years (or just never read the manual, as the case may be. but surely isn't...). These knives have the unique feature of being automatically reloadable; once a blade has been fully spend simply remove it by sliding it all the way off the end then return the slider to the fully retracted position, past the notch in the blades. Sliding forward once more catches the next blade in the cartridge, assuming there is one.

Now that we have our new blades the mission is not to install one that is active and pack a few into an onboard storage slot, as it is with virtually every other knife of this variety. Instead remove the blade cartridge by depressing the black tab and sliding outward from the back of the knife. Insert up to five blades backwards into the cartridge (it will be much easier to insert them as a single package rather than individually) until the latch actuates into their notch. Reinsert the cartridge into the knife housing and use the slider to load the active blade from the top of the stack by fully retracting it then sliding forward.

If you remove the slider you will note that the notch which selects and frees the active blade is an indentation of only a few micrometers - it is critical that when you use this knife you do not rely on the slider to retain the blade's position or you risk sliding the blade back into the cartridge or - much more dangerously - the blade may slide forward out of the housing and could even drop right out. Always make sure you use the locking knob after protruding the length of blade you wish to work with.

Reloading the cartridge is demonstrated in this video:

Things to make with a 3D Printer

A living list of things I intend to (and subsequently have) made with my 3D printer so I can keep track of ideas before they fall out of my ears and bounce away before they can make it to the printer. Or while I wait for a design to become available. Or while I wait for myself to give up waiting for someone else to do it and make one myself...

Before I bought a 3D Printer I promised myself that I would figure out at least one worthwhile, cost-saving or otherwise difficult to obtain item that I could make so I would never have the shame of being That Guy™ who buys a 3D printer and then just leaves it on a shelf. I made the same promise before buying a Raspberry Pi and have since owned four (and counting); perhaps this list will help you figure out something to do with the 3D printer you have in the mail or on your wish list that can help you avoid the shame of being That Guy (or Gal)™ too! :)

  • 18650 shoulder-short prevention cap
  • CR4040 adapter for CR3230 coin cell lithium batteries (for Microsoft wireless 10key)
  • Auto body removal tools (non-scratch spodgers)
  • Battery holders for various formats in varuous sizes
  • Raspberry Pi cases
  • Pwnagotchi cases
  • Bus Pirate cases
  • Project/demo/breakout board cases for the various ones I have in stock
  • Missing battery covers (for keyboards etc)
  • Libby's arcane weird thing: "Lian Li case clips" https://www.thingiverse.com/thing:2691439/files Lian Li PC-60FN female clip
  • Battery Organizer

Soundproof Server Rack/Acoustic Cabinet Wishlist

While Qubes will be moving to an architecture that allows you to run your AppVMs on remote machines, allowing you to employ an almost thin-client to mainframe-like architecture, when I first moved to Qubes from Gentoo as my daily driving workstation operating system the number of cores and amount of RAM available in a single system became of paramount importance on my human-interfacing edge devices. I had always wanted the reliability and redundancy features of rack mounted servers in my workstation and now an even better reason pushes me in that direction; you can get multi-socket systems just oozing with ECC ram for pennies on the dollar if you are willing to work with datacentre-focused servers that are just a few years older thanks to leasing arrangements, EoL policies and aggressive upgrading.

Soundproof Rack
Cheapest Retail 12U for ~CAD$1400 shipped

Having lost my house in the financial upheaval wrought by the COVID pandemic it's no longer a simple matter of running a bundle of actively amplified HDMI and USB cables up from my basement and into my office; if I want to use a rack mounted server or servers as part of my network operations workstation in any apartment I might find myself in while clawing my way back to financial contentment I would need to have them in the same room as me. Even modifying the fans of a typical rack mount server with resistors or throttling them though management interfaces - where that is even possible - still leaves me with a virtual jet engine next to me and this is not an acceptable proposition, especially for tasks that draw upon creative juices. The sound buggers with my chi, one might say.

The solution is to employ a soundproof rack, also called an "acoustic cabinet" but the problem is that the market for them is dominated by three companies and in an industry where brand new hardware is already overinflated in price the lack of competition has allowrd them to keep prices far above reason. Enough so that it makes sense for one to build one's own solution. While you might find it easier to start with an enclosed cabinet and seal its holes they tend to lack the kind of space between the outer panels and inner rack to do add much soundproofing material and more importantly, to construct air ducts that wind in such a way as to muffle sound while still permitting sufficient airflow that a few quiet brushless fans can provide adequate assistance to keep the now-stifled rackspace within optimal operating temperatures.

ATA Case Rack
16 space ATA Case with 19" Rack

Enclosed cabinets also tend to cost as much as half the price of their equivalently sized sounfproof options and that negates the savings necessary to make a DIY project like this worthwhile. Therefore I am leaning more toward incorporating a much cheaper open four-post rack into my design. Additionally, since moving again - and maybe again and again - is back in my future until a new house can be secured, mobility is important. I think it makes more sense to trust the selection of casters that a rack manufacturer has selected than to add another problem to my list and as such you will likely find more quater- to half-height racks and cabinets in this, my living list of potential materials that will be incorporated into my eventual work product.

An ATA Case (more commonly known as a "Road Case" or "Flight Case") enclosed rack may in fact provide the ideal starting point as they are designed with casters and substantial padding though not intended specifically for soundproofing and the enclosures are typically free from ventilation holes which otherwise need to be blocked if starting with a conventional enclosed cabinet. Replacing the material between rack and outer enclosure with materials engineered specifically for soundproofing properties may improve performance and would then only necessitate routing ventilation and adding an active ventilation system to ensure proper cooling while the devices are run inside the enclosure. In this context the term "space" is usually used instead of [rack] unit for the 1 1/4 inch standard equipment size unit and the depth of such cases are often expressed in spaces the same as their rack capacity, such that a 14 space rack in a case that is 14 spaces deep has installable dimensions of 24.5 (14*1.75) inches high by 24.5 inches deep with a width sufficient to accommodate "19-inch rack"-able equipment (approximately 17-17.5").

When (and if) finished you can expect a follow-up article, until then please enjoy and hopefully benefit from my brainstorming, note-taking and research as it grows below:


  • Though you will see pyramidal foam in professional cabinets this is mostly designed to absorb echo and high frequency sounds for improving recordings. A thin layer innermost facing the servers might be appropriate
  • An air cavity between layers of soundproofing material (any material) greatly increases efficacy and would make pyramidal foam as mentioned above much more useful than for its largely cosmetic effect
  • Bituminous foil applies a layer of this petro industrial product to aluminum or other metallic foil and was developed for the roofing profession before its excellent sound deadening properties were discovered.
  • Mass Loaded Vinyl is an extremely dense substance that provides excellent sound absorption and at least one layer should form the outermost soundproofing material layer in a soundproof enclosure.




It's Not Rocket Appliances: Selecting a Compatible Upgraded Car Battery

The 16 year running Champion

The 16 year old Interstate MT-101 Flooded Lead Acid battery installed in my Cadillac STS 4 was faltering in the face of a vicious Canadian winter that has already reached daytime lows of -18C in this particular desolate icy hellscape.I will first give Interstate due congratulations on creating a product that was able to last this long before berating them for not indicating on their site (as far as I am willing to spend time searchng) that this member of the MT series (unlike many others, so an inference was not possible) that this model is "maintenance free" which is a cute way of saying it's a Sealed Lead Acid battery with all of the drawbacks of a Flooded and none of the benefits of a Sealed - chief among my grievances the lack of a user-accessible entry point replenishing the electrolyte with distilled water as had been my initial intention to see how much longer the battery's life could be extended beyond its already borrowed time. I would note that according to Interstate's product information page the Group 101 fitment seems to only be used by two models of Cadillac. Looking at their price list and comparing the MT-101 to the notoriously similar and broadly substituted Group 78 model of the same series, one could be forgiven for assuming the 101 configuration was devised solely to impose a 100% snob tax on new Cadillac owners.


This ballache was of course escalated by Cadillac's tendency to play dress-up with their components; one assumes to hide its lowly GM origins but the net result is an unnecessarily tedious process to gain unfettered access to the battery. It should be noted that Cadillacs will tend to sound the anti-theft alarm during low battery voltage events so be sure to have your keyfob out and handy and brace yourself so you don't jump straight into the popped bonnet if and when it trips. Given the Group 101 is a side-posted battery you will, by tugging the battery cable downward and pressing the socket and bolt against the terminal as you disconnect it and then pulling both away from the battery in one deliberate motion once the fastener has completely unscrewed: avoid a lot of solenoid and relay chatter (which doesn't sound terribly healthy), intermittent alarm sounding and most importantly sparking which - I am told - is not a great thing to have happening in the vicinity of a lead-acid battery that could very well be surrounded by hydrogen gas depending on the severity of your battery's misery. Remember to start with the positive cable and then negative.

You can follow this video if a visual reference is helpful:

While the gentleman in the video uses a battery maintainer plugged into the accessory port to retain settings I can speak from experience and also from an owners' forum deep dive which included input from a Cadillac assembly line worker that it is not necessary; some owners report having to re-index the power windows per directions provided on the console but this was not my experience. For fun I rigged a similar device out of a 120V to 12V AC to DC inverter meant for powering portable cooler/refrigerators and an accessory port to accessory port cable salvaged from a device similar to his. Being capable of delivering up to 5 amperes instead of a battery maintainer's typical < ~2 one wold assume it might perform better but I chose to live without it when re-installing what turned out to be a battery impossible to re-hydrate and suffered no ill effects. While the video instructs you to push the ignition button to the "on" position it is not necessary in this particular model as all accessory ports in the cabin are always connected regardless of the state of the ignition switch. Since my dashboard/ashtray accessory port fuse frequently dies (likely from equally frequent use as a good-old-fashioned lighter, like god intended) I plugged into the port hidden in the centre console.

A search through relevant owners' forums will tell you that the preferred, tried, tested and true compatible replacement BCI group size for the 101 is Group 78. Models in this format are, according to the specification, up to an inch taller but, crucially, sport side-mounted terminals (leftmost: positive). This configuration is rather scarce among automotive batteries and I imagine for good reason. I generally find side-mounted terminals annoying, mostly for their tendency to spark while you are installing/removing the cables and in the case of my STS the way they lock the questionably designed battery cover in place, forcing you to remove the cables completely to reposition it and thereby necessitating sparky fun just to get a look at the battery. However, headroom is often an issue and with an additional inch in height (again, according to the specification...) - especially on my STS where the MT-101 had crammed its cover right up against the bottom of the cowl - I was expecting to have to perform some minor surgery or rearrangement just to fit a Group 78 anyway so top-mounted posts were ruled out.


Imagine my surprise when the MotoMaster Group 78 AGM I eventually settled on turned out to have virtually identical dimensions as the MT-101. Remember what I said about the snob tax? ....yeeeeeah. But now I'm slightly ahead of myself.

In spite of the practically unanimous wisdom of the masses I performed the battery replacement due diligence ritual I always do the first time I have to replace a battery in a vehicle that is new to me. After all, unless something goes wrong you only get one chance to upgrade your battery and when you have to cope with the kind of winters I do this isn't the kind of decision one makes with anything short of certainty that you are installing the best possible option available for your money.

The process is straightforward enough:

  1. Pull up a list of BCI battery group sizes which contains their dimensions. For this battery I used https://www.jegs.com/Sizecharts/bcigroup.html and google to fill in the blanks on some sizes that weren't included but were referred to during other research I performed.
  2. Determine which of your dimensions is the most restricted and which have wiggle room. Note how much wiggle room that is - if you are working with a solid box or sided tray then your absolute maximums have been defined and you must work within them unless you are prepared to make modifications to the vehicle.
  3. Compile a list of sizes that are within the limits of your most constrained dimension. For me this was the height of the battery, I allowed about an inch above the current model despite a tight fit under the cowl because I was already working with one of the shortest models.
  4. Eliminate those entries on the list that are too big for your more adjustable dimensions. Also drop those that are smaller than your current battery or substantially smaller than your potential maximum - we're looking for an upgrade not a disappointment and volume is the key.
  5. Rank the remaining size(s) by order of Cold Cranking Amps (CCA) and eliminate anything with lower CCA than your existing battery. CCA is the most important metric to anyone who experiences winter. CCA will vary for each size by manufacturer, chemistry, and model - even from the same manufacturer. To get a genralized idea of how sizes will tend to perform relative to one another it is helpful to find a manufacturer's listing of all their products which includes the CCA rating of as many sizes as possible. If they do not manufacture a certain size you can fill in the blanks with Google.
  6. Make your final decision, which may include considering other metrics like resilience to deep discharge or running capacity.

Starting with the Group 101's metrics, my table looks like this by the time I've run through all the steps:

Size Imperial (LxWxH") Metric (LxWxHmm) Terminals Appx. CCA (A)
Group 101 10 3/16 x 7 1/8 x 6 11/16 259 x 181 x 170 Side 650
Group 78 10 1/4 x 7 1/16 x 7 11/16 260 x 179 x 196 Side 675-800
Group 41 11 3/16 x 6 7/8 x 6 7/8 293 x 175 x 175 Top 650
H6 10 15/16 x 6 7/8 x 7 1/2 278 x 175 x 190 Top 615
- Group 48 12 1/16 x 6 7/8 x 7 9/16 306 x 175 x 192 Top 730
- Group 98R 11 3/16 6 7/8 x 7 1/2 283 x 175 x 190 Top 620
H7 12 3/8 x 6 7/8 x 7 1/2 315 x 175 x 190 Top 730-800
- Group 94R 12 3/8 x 6 7/8 x 7 1/2 315 x 175 x 190 Top 730-800
H8 13 15/16 x 6 7/8 x 7 3/16 354 x 175 x 190 Top 900

The sizes marked with a hyphen (-) indicate commonly recommended BCI group sizes substituted for DIN sizes (H*). Unfortunately all the extra work brought me was a little peace of mind; I determined that in my case the best size was in fact Group 78, for reasons not the least of which included four Motomaster variants in stock the next afternoon at Canadian Tires close to me and on the routes of already planned errands.

Crappy Tire™, Decent Selection.

Though I tend to buy Kirkland Signature batteries for Costco's amazing return policy I didn't notice any Group 78 AGM batteries on the photos I took at my local the other day (a necessary strategy if you are going to shop your local costco's battery inventory from home) and Canadian Tire's warranty and return policies on batteries are also excellent.

Costco's selection and pricing varies by store.
...and most of their AGM offerings are not for cars...
From maintenance-free Flooded Lead Acid to worry-free AGM

Among the most important and simplest upgrades you can make to a vehicle that operates in parts of the world that experiences the phenomenon known as "weather" is to switch from a typical Flooded Vented Lead Acid (VLA or commonly just "flooded") battery to an Absorbent Glass Matt (AGM) battery. AGMs, together with Gel Cells (commonly called "Sealed Lead Acid" or SLA) are one of the two types of Valve-Regulated Lead Acid (VLRA) format. These batteries - except under extreme circumstances of failure - do not leak, can be mounted sideways, are resilient to vibration, crank engines in the coldest temperatures, will rebound from deep discharge far better than any other lead plate format - even those that are not explicitly advertised as intended for "deep cycle" - and as with maintenance free batteries you can not (will not need to/will compromise the package if you) add additional distilled water in the future. While extremely old AGMs would benefit from that - as they do offgas hydrogen and decompose very slowly it is an entirely different context as conventional flooded batteries.

While AGM batteries cost tangibly more (from +CAD$60 and up) they are a sensible and worthwhile investment. It is not necessary to buy name brand AGMs like those manufactured by Maxima; the extreme premium they charge erases any advantage they might - and probably don't - have over more "generic" manufacturers like those that whitelabel for Kirkland Signature and Motomaster.

Even if you don't operate your vehicle in rugged, masculine climates - as your humble author does - it is still very often worth considering replacing your OEM flooded lead acid battery with an AGM when its time inevitably comes. Aftermarket electronics like an upgraded head unit, UHF radio or feeble compensatory sound-system can tax your battery especially if your alternator is older or declining. An AGM battery is particularly advisable if you find your sound system requires a capacitor inline with the power connection. Even without these additions, the longer service lifetime and higher performance can likely offset the steeper initial investment. Also, I've heard that at least once in one's lifetime it is common to accidentally leave the lights or some other component on or forget to unplug a device that has been connected to an always-on accessory port. That's never happened to me, of course. Despite what one may have heard. Yup.

My car is sarcastic.
My car is an arsehole, too.