Tips On Making a Delrin Folder

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In this scene from Stanley Kubrick’s classic 2001: A Space Odyssey, the ape is dissatisfied with the properties of natural bone. I suspect he wants a Delrin club. Here is a great explication of the film.

Seriously, animals do tinker with their tools, and so can you. It is an intensely satisfying experience. It gives you a lot of freedom and confidence in designing, executing and using a specific tool for your individual needs. It is interesting to see how tools you have made wear, perform and even may fail in use.

While bone can only be harvested from dead animals, Delrin is mass produced and easily obtained from many suppliers. It is a very hard plastic, originally invented by Du Pont in 1960 to bridge the gap between plastics and metal. There is a dust hazard, as there is for wood, so you should review the MSDS and wear PPE.

MAKING A DELRIN FOLDER IN FIVE EASY STEPS

1. PLANNING.  It is a good idea to think and experiment a bit with what you like, or don’t like in the folders you are currently using. Monica Holtsclaw has a great introduction to various shaped folders for various purposes. How do you hold it? Do you use both ends? Do you like sharp or rounded angles? Is it for scoring, folding, and/or burnishing? What different operations do you intend to use it for? Making a crude mockup out of binders board glued together for thickness can give a much better sense of what the actual product might feel like and fit your hand. Alternatively, full size scale diagrams are also quite informative. Here is my idea of the ideal shape.

2. ORDERING MATERIALS AND TOOLS.  Obviously, it is easiest to order the Delrin closest to the size you need for the final shape. Mc-Master Carr carries an extensive variety of sizes, but consider yourself warned; their website is more addictive than cheap baggies of high potency heroin. As far as tools, I recommend a 24 tpi hacksaw if you don’t have a bandsaw, a small vice, an 8-inch coarse bastard file with handle, a woodworkers card scraper, a burnisher for putting and keeping the hook on the scraper, and an assortment of 3M sanding sponges for final polishing.

3. ROUGHING OUT. Delrin is easily marked with a soft pencil. Cut it out using a bandsaw or 24tpi hacksaw. The more care you take in cutting evenly and accurately the less time you will need to spend cleaning it up later. A bandsaw makes the roughing out much quicker and I find it easier to get a more accurate cut. Indeed, a bandsaw makes everything — even mistakes and accidents — much quicker.

4. SHAPING. Initial shaping is most easily accomplished by filing. I prefer an 8 inch Nicholson Magicut.  It works well on wood, plastics and laminates. I find the older ones made in USA better made the the newer imported ones. Alternatively any coarse bastard file can be used. Always mount a handle, otherwise the tang can cause serious injury. Grinding or sandpaper tends to produce very deep scratches that are difficult to remove, and I would be nervous about the amount of dust generated. I have experimented a bit with a plane and spokeshave, which kind of worked, but resulted in lots of chatter, unpredictable chipping, and a difficult to clean up surface. It can also be shaped with metal working tools such as a milling machine. And who isn’t looking for a good excuse to buy a table top milling machine?

5. FINISHING.  I find hand scraping (with a woodworkers card scraper) produces the most successful surface finish after filing. You will need to learn how to sharpen it and turn the burr. Scraping is also virtually dust free, since the shavings are a couple of a thousandths of an inch thick and tend not to become airborne. There is some other good advice on finishing Delrin from this thread in the Practical Machinist. In general, the finish of Delrin reflects the tool used. Delrin is very clean and nonabrasive, consequently your tools stay sharp for a very long time. It is a great way to learn about scraping, since it doesn’t have a grain direction to worry about like wood.  A final polish with a progression of 3m sanding sponges, gives it a pretty good finish. The higher the polish the easier it is to clean, and I find the more bone-like it feels.

Delrin is not yet easily available to use in a 3d printer, though I suspect it will be in a couple of months/ years. This could be very cool: one of the most useful and intimate bookbinding tools to be customized and printed on demand. For now, stock reduction is not all that difficult. I’d be interested to hear if anyone has experimented with other plastics for folders.

If you have a bit of experience shaping metal or wood, Delrin is not that different. It is a slightly challenging, but rewarding material to work with hand tools. If making tools is not your cup of tea, you can always purchase a ready to use folder from me, and use this info to tweak it a bit to suit your personal preferences.

I’ve planned a workshop on making Delrin folders. I’ll give it a test drive in a couple of weeks on full time North Bennet Street School bookbinding students. Contact me if you are interested in hosting something similar at your location.

 

delrin in progress

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