Pen Blank Press

This is a jig for making and gluing up pen blanks from wood discs. It is pictured loaded with discs clamped as for gluing, with a sampling of discs around the base. Sometimes I actually make a thing on the Glowforge. Mostly though I make the thing that makes other things. This is one such tool.

The base has 1/4x20 threaded inserts into which are seated two threaded rods. The center rod is aluminum that has been polished shiny and waxed. The top has matching through-holes for the 3 rods. Acrylic plates line top and bottom to ensure the discs don’t get cemented to the wooden base or top.

Since the wood base and top are too thick to cut, the “made on a Glowforge” bit is that scrap wood was used to make drilling patterns for the top and bottom, as well as the acrylic plates.

From a design perspective, it is convenient if the top and bottom do not need to be lined up in a consistent left-to-right direction. To achieve that the spacing of the rods from each other and their centering in the wood blocks along two axes needs to be precise. That takes a fair bit of skill to achieve with normal woodworking tools, but is drop-dead simple with Inkscape and Glowforge.

The design requires three templates:

  • The drill template for the bottom has a hole to fit the aluminum rod but the other two holes are sized to position a drill bit large enough for the threaded inserts. Length and width match the bottom block of wood.
  • The template for the bottom layer of acrylic is similar but the holes are sized for the aluminum rod (6.5mm) and the two 1/4x20 rods, which are much smaller in diameter than the holes for the threaded inserts.
  • The top template has the same hole pattern as the previous one, but length and width match the top piece of wood. Two additional holes are cut to allow small screws that hold the acrylic loosely to the wood.

Since the holes are precisely spaced, grouped, and centered, the top part of the clamp slips on easily regardless of left/right orientation, as per the design spec.

The discs shown are also cut on the Glowforge. The center holes are intentionally snug on the aluminum rod to help hold the disc alignment during assembly. Some projects call for all the grain to be aligned, while others might call for it to be staggered or crossed from layer to layer. In either case you want to discs to be somewhat resistant to rotation from a careless touch. The glue has a tendency to reduce friction and the snug hole size attempts to compensate for that.

Here it is in action and demonstrating the need for the acrylic bottom plate. Once the clamp is fastened on and screwed tight there will be considerably more glue squeeze-out. Since PVA glue bonds are often stronger than the wood itself, and since the clamp is made of oak, the whole thing would be a 1-time-use sculpture jig without the acrylic.

The first project off the jig is presented over at the Coral Snake Pen topic.

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this is fantastic. i’m literally just about to start a pen blank project like this (a stack of discs).

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Good luck! Be sure to post the result. What’s your planned pattern look like?

Incidentally, I didn’t post the files for the jig because I based them off of the random scraps of oak I used for the press. The main thing is to make sure the three holes are equidistant. The centering in the wood is less important because as long as the holes are in register top and bottom they can be off center.

The aluminum rod was purchased 1-off in order to get the size I wanted. My intent was to produce blanks that would require drilling, even for a 7mm tube. This ensures that the glue surface inside the drilled hole is smooth and presents a fresh wood surface unspoiled by glue or scorch marks. The aluminum rod is 6.5mm.

Do NOT use your pen mandrel for gluing! Even after shining up and waxing the aluminum rod, the blank sticks to it to the point it needs to be tapped out. Consider the rod a consumable item and plan to replace it eventually. Though it is pretty durable, as consumable items go.

Wing nuts can be used for the clamp, although proper star knobs are MUCH easier to clamp down.

Have fun!

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Thanks for sharing this.

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Hey @shop, I forgot to mention, this reminded me once again that no plan survives contact with the real world. After putting this to use I realized it would be more convenient if the threaded rods were further apart. As-built, it is difficult for me to grab the blank for removal, or to get my hands in around it to clean the squeeze-out off after clamping. I used oak for the base and top so it would have been more than strong enough to accommodate the wider spacing, had I thought of it first.

Might want to test spacing out on some scrap wood prior to final design. Don’t even need a template or the trouble of threaded inserts. Just drill a series of holes, push the threaded rods through, and test the fit. When you find one you like, add about 3/4 the diameter of your discs and you have your rod spacing.

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it’s leftover scraps from making my Measuring Totem. so i have four species (walnut, basswood, cherry, and padauk) in multiple thicknesses (from 1/16" to 1/2"). so it’s going to be a mix of woods/thicknesses. plan on making two. one for me and one to give the person who asked me to make the totem for her (and it was a work project, so i at least got paid my normal hourly pay to make it).

i’m going to have to be very snug and hope it works, because i don’t have a drill press and don’t plan on drilling, if i can avoid that. if my first test doesn’t work, i’ll have to find a friend w/a drill press.

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If you have a set of disassembly punches, or even just a rod smaller than the one used for the jig, it is possible to tape a piece of sandpaper to it and use a hand drill to smooth out the interior. Something like 120 grit cut into a 1-inch strip just long enough to wrap around the rod a couple of times usually works for me. Doesn’t have to match the diameter, just needs to fit inside with enough cutting surface to do the job.

Of course, the main reason drilling a blank is so problematic is that the hole needs to be centered. Since these discs already have a hole in them, a normal drill bit (not a brad point or mini-forstner, but the kind with an angled point) self-centers. You could probably use a hand drill instead of a press. (With the blank in a vise or clamp and not your hand, obviously.)

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Awesome project, and I love the pens you made in your other topic. Always an adventure to read your posts!

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Making tools to make tools; you’re my kind of guy.

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There may be two other options. First resin mold release, it works on resin. Second, hdpe rods. Not sure the come in metric or sizes, but probably do. Also, you could cut the center hole to the thickness of the pen tube, using the extra long tubes you can buy. Then cut to length. :thinking:. I like your pen tube jig. Yet another :rabbit2: :hole:

How thick is the thickest disc you cut?

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Assuming you mean for the rod and not the clamping surfaces? That would probably work too. I polished the aluminum rod on the lathe and the wax was right there. Same stuff I use on pens so availability prevailed over optimization.

Couple of problems here. First, some of the woods are very oily and the scorch marks resistant to glue. So either don’t use oily woods or else that center hole needs to get cleaned out. My method requires drilling but works on all timbers.

Of course, I have everything set up for drilling anyway so it isn’t an inconvenience at all. The calculus might produce different results for anyone who isn’t set up to drill blanks. Then again, the pre-drilled hole means it should be possible to use an ordinary (not forstner or brad-point) bit to drill to size and probably a hand drill would work just fine.

The other issue is that the extra long tubes don’t come in many of the sizes I commonly need. They need to match the bushing diameter on the inside and must be thin enough so the blank doesn’t end up too thin on the ends. I have had tubes with the correct exterior dimensions but too small to fit the bushing, and tubes that fit the bushing and the OD exceeded the large part of the bushing. I do have a fairly large stock of tubes though.

The other issue with pre-glued tubes is that the blank needs to be squared perpendicular with the tube. With precise lasering this would be possible if the press is precisely aligned. To use this method I would make a few modifications to the press to boost the precision just a bit.

All of the kit manufacturers sell blank-squaring sleeves with an ID to fit the pen mandrel and an OD to fit the pen tube. Using an actual pen mandrel rod as the center rod of the press allows the use of these sleeves to ensure the blank is precisely aligned to the center rod with zero racking.

The other modification would be something to ensure the blank is square with the base under pressure. I do not have any tiny precision squares but the laser is precise enough to cut a mini-square tool to check alignment of the blank to the base. If I were doing long tubes with plans to cut blanks out of them, a regular square would fit - but the racking would be worse so I’d add something to prevent racking. Possibly put the press between two cauls and clamp those.

That would work. In my case, a question of availability again. I had some aluminum rods leftover from a batch of rolling pins I turned a while back. Incidentally, the HDPE is resistant to glue but unless the surface is polished and maintained it deteriorates over time. So, still a consumable item. (Kallenshaan Woods sells several types of non-stick rods to help assemble their kits and I know from experience that they deteriorate in this fashion.)

For this project, 1/4 inch. I have cut thicker stock but only soft woods and only with close supervision. I keep a fire extinguisher next to the GF as a precaution. I inherited a scroll saw a while back and I keep threatening to unbox it for thick stock but have yet to do so. Instead I keep figuring out how to do the project with thinner stock and laser it.

Incidentally, the bloodwood is extremely difficult to cut but I managed to get 1/4" discs from it.

Thanks! Me too. The first couple of blanks came out as well as I’d hoped and I have plans for some more interesting designs.

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