Prusa Spool Upgrade

When I got my current 3D printer, I quickly upgraded the spool holder.  The original worked ok, but was a pain to load and adjust in width.  Every spool manufacturer has different widths to their spool.  The spool support I found on thingiverse was easy to adjust and load.  Eventually it had issues though.  The black threaded shafts that held the bearings in place started breaking off.  I installed 5/16″ bolts as a replacement.  Left photo was the original installation, right photo shows my bolt mod.

As those shafts failed they caused a lot of rolling resistance on the spool, and it ended up failing a few prints before I diagnosed the issue.  The bolts help, but there is a fundamental issue.  They hold the spool at the outer edge.  Any force imparted is a long distance from the axis of rotation.  If it were held in the center, then it would take a lot more resistance to induce the same torque.  That is how the original supports worked, so maybe they were on to something.  A diagram might help.


The extruder will pull at roughly the same angle and with the same force in either setup.  A full spool will be heavier and require more force to spin, but the filament will be at the outside edge, far away from the axis of rotation (red cross hairs).  This produces higher torque.  Think of putting a pipe on a wrench, you can push further away from the axis of rotation, which makes more torque.  My old setup (left) held the spool at the outside edge (orange dots), far from the axis of rotation.  My newly devised holder (right) runs through the middle.  Even if it doesn’t spin well, it can’t impart that much torque on the spool.

I heard Adam Savage give a good talk about how everything you try involves a lot of failure and trying again.  He was suggesting maker spaces nail to the wall (literally) the progression of projects to show that it takes effort and that nobody gets it right the first time.  I wanted to show some of my work on this one.


First I needed a way to hold the spools.  I decided a center hub (for reasons explained above) was best.  After measuring all my spools I set the outer lip just small enough to pass through the hubs, then made the center area a little smaller so the spool can’t walk off the hub.  Pressed in bearings mean it spins really effortlessly.  I had a bunch of red filament, so I started with that.  It was simple and worked right the first time.  So much for showing progression!  The next task took an extra try or 4.  I used jam nuts to hold the two spool halves (they are identical) together.  Don’t tighten the nuts against the hub, the bearings spin better without side loading.  To make handling easier I printed a handle with internal 5/16″ threads.  The first one was too short for my hand, so I cooked up a longer one.  The threaded rod goes 2.5″ into the handle.

This hub system will need some kind of support to keep it up high on the printer.  I took some measurements of the printer frame and started with a thick test piece to make sure it would clip on and be secure (far left).  I thought it was good enough and went forward with a full spool support (second from left).


This worked but was a little too thin and wobbly.  The odd rounded rectangle cutout is for my LED strip.  It was too close to where the spool will be.  I couldn’t have the light and spool installed at the same time.  Next I made a few minor adjustments to the frame clip and printed another test (middle).  That was more snug.  I moved the LED strip to a reasonable location and tried again (second from right).  I ran with this one for a week or two and liked the results.  The only changes to the last version was to increase the thickness for slightly less wobble, and an extension of the hub shaft holder.  My current spools fit, but a future spool might be larger in diameter.  The final design was printed in Prusa orange (right).


Everything fits together nicely.  The large flange on the handle keeps it from sliding up your hand, and aids in alignment.  My LED strip slides in its slot with a little wiggle room.  The uprights can move if need be, but are in a good place.  The center hub is wide enough to accommodate a large range of spools.  I think this will be a great holder for a long while (until 5 minutes after this post when I run into an issue with it!).

This should be compatible with any of the Prusa i3s.  I think the MK1, 2, and 3s all have the same size and shape frame.  If I am wrong on that, then this only works for the MK2.  I uploaded it all to thingiverse.

As a bonus, it is holiday time, and that calls for cookies.  Cookies that come in fancy shapes taste better than normal ones.  True fact!  Add some pizzazz to your holiday gathering.


Woodsaw 3D Printed Parts

Miter Saw Zero Clearance Insert

Sawing with a tight fitting insert is almost always the right way to go.  It supports the wood being cut and prevents the fibers from getting torn as the saw teeth punches through.  The plate that comes with the saw works, but has a wide gap.  I made a thin plywood insert, but they don’t last that long.  This is my attempt at a 3D printed one.  The original is on the right.  Notice how wide the saw blade gap is.  I took a picture of the original saw plate on one of those self healing cutting mats.  They have good ruled lines in both directions to make sure the image didn’t get distorted.

The first print out of the gate fit really well.


I made the first cut with no wood in the way.  It chopped right through the plastic and cut a self fitting slot that is just exactly the size of the blade.  I might have been a little too cautious.  Slow cutting built heat and there was a bit of plastic fuzz at the top edges of the cut.  A little light work with a utility knife had those cleaned up.  Some subsequent cuts have shown the insert to properly back the cuts.

I still need to find a spool of Dewalt yellow filament.

UPDATE: Decided to upload it to thingiverse.

Table Saw Organizers

I am in a near constant state of looking for pencils and rulers/tape measures.  I should attach one of each to my body with a short retractable cable.  Until then I try to stage as many as possible at each work station.  At my table saw I made two different organizers to hold commonly used  items.  They both attach to the far side of my rip fence.

The white organizer holds my wooden ruler and a small stack of pencils.  The pencil well could have been a touch deeper, but otherwise it works well.  The yellow holder area keeps my grrripper push block.  It is at a really convenient hand position for quick use when sawing.



June 2017 3D Prints

Lots of good prints this month.  I have got the new printer pretty well figured out and have ventured out into new materials and longer prints.  First up is a cool blade guard I made.  I picked up this nice boning knife for bbq goodness.  It is crazy sharp but came with no guard.  I printed a two piece guard with magnets set into the one half.  The two bits glue together.  It keeps the edge and my fingers safe and fits snuggly.



Porch Cup Holder

I have some Adirondack chairs on the back porch.  They are reasonably comfortable, but have a distinct lack of cup holders.  I fashioned some a while back out of wood, but the sizing was all wrong.  These are perfect.  They hold coffee cups, large tumblers and small glasses alike.  The RTIC’s blue handle was printed back in September and is still alive after daily use.  Thingiverse Link

Thermocouple Kickstand

I got a cheap thermocouple reader for reasons beyond my obsession with measurements… I swear.  It works well, but didn’t come with a kickstand.  I am used to all my multimeters having some way to sit themselves upright.  This one clips together, then slides on snugly.  It doesn’t add too much bulk and stands steady.


I have a few high temperature projects, so it is time to venture beyond the safety of PLA.  It is a great material to print with, but loses strength quickly when things get hot.  Enter PETG.  It is higher temp and strength like ABS, but less toxic, and lower warping.  One of my firsts was the Franken-Cooler.  Not without issue, but largely a success.

Next I made a small clip to keep the USB cables in my car in order.  They always get pinched in the lid when I close my center console.  This will keep them in the pass through.  Simple but effective.  I needed the higher temp material because cars get hot in Florida.

I made some mods to the camera setup on my prusa.  Someone made a decent set of parts to attach a common webcam to the Y stage.  The only problem is their main bracket was a bit loose.  I started with PLA because that was all I had.  It sits up against the underside of the heated bed.  If I need higher bed temps the part could fail.  I designed a lighter tighter fitting version with speed holes to help cord wrangling.  The PETG part will not fail due to excessive bed heating.


While I was at it I found a lens adapter that could replace the original webcam lens with a very wide angle one.

The new lens give a much better view of the print bed.  I can see the whole thing instead of just the middle third.

Screen Shot 2017-07-05 at 7.54.08 PM

Finally I can take time lapse videos that don’t look terrible.  Behold the birth of a baby groot.

April-May Prints

April was a pretty quiet month for printing because I knew the new printer was coming.  May turned crazy once I got the prusa up and running.  I already posted on my battery storage and drawer divers in another post.

Salt Grinder

A co-worker had a cool salt grinder that kept breaking.  He wasn’t able to get refurbs anymore, so off to printing we go.  The body is heavy stainless, but that center window is very thin plastic.  It falls over easily and snaps off the threaded area.  I printed a tapered part that threads and glues into the spot where the plastic window was.  In addition I made a little stand for it to sit in so you can’t knock it over as easily.

Tape Measure Pocket

I typically use a tape measure at the table saw to set the rip width.  It works, but I think a wooden ruler would be more reliable.  I printed a pocket for it to attach to my table saw side so it is always close at hand.

Wonderful Wooden Filament

Not exactly the same as woodworking, but fun none the less.  They make wood dust filled filament.  It prints well and has a neat texture to it.  This stuff was made for printing baby groot!  I tried a set of benchy boats; one stained, one not.  It doesn’t appear to stain well, but made a great looking fidget spinner.

Desk Trophies

One of the criticisms of 3d printers is that they are only good for printing desktop trophies.  They are good for lots of other things, but yeah, they make awesome desk trophies!


Bit Holders

Ok, back to useful prints.  I wanted to better organize my various driver bits, so I made these organizers with nice spacing for you to get fingers in and pick out the bit you need.  The markers are made using prusa’s multi-color print.  The one where you switch spools at a set Z height, not the one that changes color mid-stream.  I couldn’t do that on my last printer, but I am very happy it works on this one!  Too bad they don’t sell filament in dewalt yellow.

Mom Stuff

Don’t look mom, this is all going to be a surprise for you!  My mom wanted some altioid tin organizers and paint holders.  I figured she could also use pen/knitting needle/cable storage stuff as well as some funky knick knacks.


Arbor Press

I picked up a cheap arbor press for pressing bearings, pressing printed parts, etc.  I made a number of arbor press fittings sized just for skate bearings and bolts.  They have a square hole that gives a perfect friction fit onto the arbor press end.  The printer also provided a nice glue on storage rack for my press ends.  I couldn’t help myself with the two color printing, and made a crush hazard sign.  Watch your fingers.  I should print some pirate flare and turn this thing into an ARRRRRRRRbor press.


Last but not least I found a cool box on thingiverse for holding spare printer nozzles, a handle for turning reciprocating saw blades into short hack saws, and a penny powered fidget spinner.


I probably forgot something, but that is enough for now.  Since getting the new printer I have printed for 136 hours, and pushed out over 800 meters of filament.  That is kind of impressive.  I can stop any time I want.

Prusa I3 MK2s Build

I finally got my new printer.  Nearly 2 months after purchasing it shows up the day after my birthday!  That is one serious adventure in a cardboard box.


I rolled out some paper onto the dinner table and got rocking.  I couldn’t help but setup my gopro and get a time-lapse of the assembly.

The total build time was between 5 and 6 hours plus some tweak and tune time.  The first print had to be the prusa logo in honor of the great maker.

Print baby print

A post shared by Chase (@kiltedcraftworks) on

With it up and running I got to bootstrapping.  The kit comes very complete, and really is a wonderful printer.  That having been said, the little knob they included to run the interface isn’t great.  It rubs and is awkward to use.  Print a new one!


A lot of my filament is from when I first bought the monoprice back last summer.  It spent a lot of time sitting out collecting dust.  Someone made a nice clip in dust filter that goes right on top of the extruder.

Next came a replacement for the spool holder.  The one included works, but you have to sort of bend it out of the way to get a new spool on.  Plus something with bearings would DSC_0832roll a lot smoother.  Any catches or resistance in the spool rolling could cause Z banding as the extruder fights to pull in filament.  Thingiverse had a great assembly that sits on top.  It included a printable threaded nut and bolt that turned out gorgeous!  Skate bearings pressed into the rollers so the spool rolls with little resistance.  A filament guide keeps it running true.

Speaking of spool holders, my one major disaster so far has been this print job.  Sometime over night the extruder actually pulled the spool off the holder.  Nothing broke except the filament guide (just print another).  It turns out the spool was wrapped poorly and kind of synched itself off.  Poor spool wrapping perhaps.

I monitor all my prints with a webcam and octoprint.  This works out well while on the other side of the house, or on the go.  The only trick is that I have to leave a light on after dark.  Instead of leaving the room lights on constantly I designed and printed some brackets for holding thin under-cabinet LED lights.  Serendipitously one light will fit in a slot the spool holder had.  Only a small printed wedge was needed to keep it secure.  The other two went on my bracket.  It clears the extruder at full height.

It is turning into a proper looking monster!  Let the print games begin.