Tumbler Sanding

Long story short: I tried to use a tumbler to conformally sand 3D prints and clean up old metal parts.  It didn’t work that well.

Long story long: I wanted a way to sand complex parts such as 3D prints and old tools.  I can convert rust easily enough, but it leaves surfaces dark, and doesn’t handle other grunge.  Sanding 3D parts works, but never gets the nooks and crannies right.

Enter the tumbler!  It is a funny shaped open top globe that vibrates.  Shooters use them to tumble brass bullet casings to clean them up.  I started with sand because it is abrasive and cheap.

No luck, sand didn’t do much even after hours of work.  How do the rock tumbler guys do it?  Silicon carbide grit.  Lovely!  I will buy some and mix it with my sand.

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Watching it combine with the sand is a really fun trippy experience.

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I tried lower concentrations of carbide grit to sand, but eventually added the whole 5lb bag of grit.  The metal and printed parts both spent 2-3 hours in full concentration grit.  I feel like the metal parts may have benefited.  It is a little hard to tell in the photos, but the metal is a bit cleaner.

The 3D prints didn’t show much improvement.  The sanded one was a touch smoother in places, but picked up a lot of staining from the grit.  None of the ridged areas were knocked down well.  On the plus side, delicate features didn’t break off.

Poor pickle rick is just going to have to remain rough around the edges.  Don’t buy a tumbler and grit to sand your 3D prints, it doesn’t work well.

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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.

 

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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.

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.

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Cutting Corners

This was a fun collaboration with my dear madre!  She does bookmaking along with letterpress and about 100 other hobbies.  See where I get it from?  When making a hardcover book you have a solid material that is covered with something like fabric or heavy paper.  I forget all the terms, but in order for it to get covered nicely you need to cut the corner off the cover material so it folds in well.  It is kind of like wrapping a present.

I was directed to check out the cool 3D printed corner tool here: https://www.ibookbinding.com/tools/3d-printed-corner-cutting-tool/

It was a good looking tool, but the tall wall used to protect fingers made it a lot harder to use.  In woodworking we use guides like this all the time to cut knife lines in wood.  You want it to be low so you can get a flat single beveled knife up against the guide.  I made a few changes and came up with this.

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It sits on the corner of binding material up to 1/8″ thick, and provides a 45 degree standoff of 1/8″ from the very tip of the corner.  I added that funny circle cutout to make sure the printer didn’t round the corner to the inside any.  This sits snugly.

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Here is an example of a binder board and the cover material.  The tool sits on the corner of the hard binder material.

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With fingers sufficiently out of the way, you can run a knife along the outside edge and trim the corner off.

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With all corners trimmed you can do a little fold and crease and get a smart looking book cover.

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Mom was happy and requested a dozen.  Easy enough!  Thingiverse link for those that want their own copy

Drill Caddy

I am in a caddy mood for some reason.  Having organized grab and go tool sets make life easier when you have a problem to solve somewhere.  Most repairs don’t happen within arms reach of the tool box.

Up next is this zazzy little 12V drill driver.  It is small and highly controllable.  I like it for use as an electric screwdriver for assembly/disassembly and for installing small and delicate hardware in wood.  First you need a holster.  I did some careful measurements and in just 1 iteration came up with this design.  It is easy to insert and holds really well even through heavy shaking.  The key was how it catches on the pull out chuck.  A rounded leadin helps it find hold, but a square edge keeps it from erroneously falling.

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I attached this to a piece of wood and started carving off a handle area at the bandsaw to give more finger room.  This needs to be the most accessible thing on this caddy.

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With the gun set in place I could start planning out other accessories.  satisfied I had enough room everything got a coat of paint.  My blue was running out so it is a little spotty of a job.  Once everything gets installed I doubt it will be noticeable.  It would be great to buy Bosch blue and Dewalt yellow filaments and paints.  I bet a lot of effort goes into picking the colors for tool companies, and they don’t want to give those away.  Plus I have way too many paints and filaments, I need to use my current stash.

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I had a pretty good idea at this point where I wanted everything from the layout stage.  The only change was the addition of the bottom blue short bit holder.  I was running out of “wall” space and realized that would be perfect.  The nut drivers came with an odd loop on the holder.  It made building a little slide on clip easy.  The red case is full of a zillion standard and security bits.  No hardware is safe from me!

The handle is a copy of the previous design with a switch to red to keep with this color scheme.  The kobalt set has some decent quality standard bits, sockets, and a basic assortment of drill bits with hex shanks.  I don’t plan on doing much drilling with this, but occasionally they might come in handy.  Ok, what needs fixing?

The only thing this might need is a removable magnetic parts tray.  Maybe a clever, secure yet removable, design will hit me in the shower.

Zip Tie Caddy

Zip ties are one of those magical inventions that are simple genius, and I can’t live without them.  I have a fancy zip tie gun at work that does a really good job of tensioning the tie, automatically cutting at a set point, and keeping the tail captured.  They are expensive, so I found a different design that works pretty well and is affordable by mere mortals.  This calls for a custom caddy to keep all my zip ties organized and ready to go.

I cut up some spare plywood and played around with layouts a bit.  I think this is a good size.DSC_0899

I cut out a window to make tool access easier.

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I cut some more wood for a small base.  Narrow enough to make storage easier, but wide enough to keep it from tipping.  I really like how the rounded corners turned out from my router jig.

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I gave the two pieces a good painting and assembled.  I picked the color scheme of the zip tie tool.  The black zip ties contrast nicely against the orange background.

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To attach each zip tie bundle I used a zip tie that can be screwed down.  That looped into a zip tie around the bundle.  As you pull ties out you just tighten the bundle to keep things tight.

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It holds a variety of lengths and sizes along with my colorful re-useable ties and the screw down ones.  Plenty of room to grow too.

The handle was printed to match my hand size and keep with the color scheme.  Same deal with the zip tie tool holder.

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Corner Radius Routing Jig

Two hobbies collide as I print something super nifty for my wood habits.  A cool thing you can do with router tables is apply a template onto wood, and use a templating bit to match cut.  The bit has a bearing of the same diameter as the cutting edges.  It rides against your template and cuts away any underlying wood that isn’t shaped like your template.  Super handy, but you need a good template to start with.  Enter the 3D printer.

I modeled up this little jig so that it hooks onto the edges of a board and gives an exact radius.  It is hard to see given the color, but I printed a 1″ text in the bottom to note the size of the radius.

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Here is a picture of the jig fully seated, and what the resulting cut looks like.  Very clean and smooth.  The large circular cutout gives a lot of finger purchase so you can hold it tight and far away from the spinning bit.

One concern I had was with the material.  Would the cutting friction heat up enough to melt the plastic.  I did 4 cuts on a 3/4″ bit of plywood and everything looked good.  If I had a hundred corners to do, I would worry.  I could always upgrade to PETG.

The part is available in multiple sizes on thingiverse

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.

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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.


PETG

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.

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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.

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