Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Built a scanner? Started to build a scanner? Record your progress here. Doesn't need to be a whole scanner - triggers and other parts are fine. Commercial scanners are fine too.
dpc
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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by dpc » 15 Apr 2021, 12:20

Or maybe dpc could cut some mounting blocks from plywood or other board for you?

Sure. I have a table saw and a variety of other tools and lots of scrap material. I don't want to get into the habit of making scanner parts for people, but a one-time thing is fine. Send me a drawing of what you need (photo of a pencil sketch with dimensions noted is fine).

Doranwen
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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by Doranwen » 15 Apr 2021, 12:34

It's sounding like regular acrylic is definitely the best choice here. I'm also quite glad that Michael's is right there - I won't have to worry about waiting for it to arrive from somewhere (and if we do crack one of them somehow, I can always buy another without needing to wait).

I emailed my brother again and told him to read the last posts so he can see the discussion - he's the one who needs to answer those questions, lol - but I'm pretty sure he has at least decided to figure out a 100° angle one way or the other, so that should solve the reflection issues without adding in blurriness on small text - I hope!

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by cday » 15 Apr 2021, 14:27

For the platen I had in mind at each end of the ‘V’ shape a triangular block with an included angle of 100º, with the acrylic screwed through two holes drilled in each side. Screwing through the sheet into pilot holes in the block seems better than trying to screw into holes in thin acrylic, as David Landin did.

The plastic board I have has a rigid foam core which takes screws well, and is around 0.70” thick so slightly thinner than 3/4”. If the triangular pieces were around two or three inches high when inserted in the platen 'V' they would be very light and should provide secure mounting for the acrylic sheets, probably better than the small plastic blocks that David Landin suggested, and possibly better than the small metal brackets illustrated, which would have to be bent out to 100º. The plastic board offcuts I have are from boards widely used here for fascia and similar boards on houses. I don’t know if similar material is used in the U.S., but that is probably academic as it is unlikely that dpc has any offcuts.

I have been thinking about the best way to cut some blocks using my power mitre or circular saw, given the the need for left and right cuts, and the need to be able to hold the board for the second cut without wasting too much strip length. It has only been an intellectual exercise so far, as I like to use my circular saw and mitre saw outside, and there have been some very cold winds recently.

Something similar could, of course, be made from lumber sheet, maybe MDF if it will drill and take screws reliably, or plywood, or maybe hardwood sheet would be ideal as it would probably have a finer grain. Other designs are of course possible, including designs that could allow the acrylic sheets to be removed for storage, but simplicity and low weight are probably both desirable.

For the 100º book cradle, I have already suggested a possible simple solution using standard 90º metal brackets, but I’m sure that dpc can see ways of cutting suitable mountings for the MDF sheets which could be screwed to the sliding baseboard, from whatever board he has available, if he can see any advantage in doing that.

With a 90º platen angle the two perspex sheets butt neatly against each other at the bottom of the ‘V’, which David Landin mentioned was ideal when the platen was pressed into the centre of the opened book. As the following illustration shows, that isn’t quite the case for a 100º platen. Ideally the bottom edges of the acrylic sheets would be cut at a slight angle so that they could butt together, but while it might be possible that probably isn’t a realistic option, and dpc has mentioned that placing something under the centre of the book would assist in inserting the platen into the book.

Platten 100º.png

Any thoughts on those ideas?

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by dpc » 16 Apr 2021, 16:49

If being able to break down the platen into two planes for storage isn't a concern, it might be easier just to glue a crosspiece of acrylic strip across the ends (forming a triangle - inverted 'A').

As Landin mentioned, that acrylic cement will melt the mating pieces of acrylic and make a strong joint. If you glued it on the crosspieces on each end and along the gutter seam where the two planes touch I'd imagine it would be a reasonably strong assembly. If you purchase 12 in. x 12 in. sheets of acrylic you'd likely trim them down resulting in at least two scrap strips that you could use for this.

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by Doranwen » 19 Apr 2021, 13:58

Sorry for the delay in getting back to you all. My brother has been swamped with things and thought he'd responded to my email, only to discover he hadn't. He called me last night to give me his responses.

He says thank you for offering to make parts, but thinks he's gotten the attachment stuff worked out. We'd like to stick with the final design (using brackets/corner pieces to attach) but he thinks he has that sorted out. The challenging part is going to be to get the acrylic edge ground down to the right degree to put together (since they're not going to meet at a 90° angle). He says it needs a power miter saw, which is something I don't know anyone around who has right away; I'll have to ask around and see.

He's fairly confident that the 3/4" pipe will do quite nicely and be strong enough. He plans on going with me to shop for that stuff because it'll be things Home Depot carries all the time and should have.

My next things to do are to actually purchase the acrylic (regular, not anti-glare) and work on finding someone who can grind the edges down, and obtain the bluetooth remote I'll need for triggering the shutters on the smartphones I'm using for cameras (I missed ordering that with the other stuff, but I should be able to add it into another order within the next month). At that point I should have the more difficult-to-source parts and it'll just be down to the everyday easy-to-get stuff that he'll be able to get with me.

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by cday » 19 Apr 2021, 14:33

@Doranwen

I would hold off buying acrylic for the moment until the 90º v 100º issue has been fully finalised, I don't know what general timescale you envison for your brother's visit?

@dpc

Can we take it that you have at some point built a scanner with a 100º platen, and if so did you use acrylic or glass?

Looking at my drawing above of the end view of 90º and 100º platens, do you have any comment on the end view for the 100º platen, which is not as neat as that for the 90º platen? The fact that the two sheets don't butt together neatly might slightly complicate assembly, although it shouldn't be a barrier. And also from the point of view of easy insertion into an open book?

Like you I intuitively feel that the two pieces of acrylic would be better joined along the length: I can imagine them possibly separating slightly when the platen is raised, and being more likely to deflect as the platen angle is increased to 100º. On the other hand, they could tend to be forced together as the platen is inserted into the book, and in David Landin's final baseline design they were not joined.

With regard to joining them, David Landin makes the following comment which could be relevant to a 100º platen:
You need very little of this cement, and you do need a very crisp, clean edge to the plastic, so that the edge of the plastic make an excellent contact with the sheet it is being glued on to.
You or I could probably cut the two edges that join at a slight angle so as to get good contact, but I don't see that as being a practical option generally. And if linking the two pieces is worthwhile, then I would think that just joining them securely at spots say 2" apart would probably be sufficient, and safer than trying to join them along the whole length. Maybe a general purpose adhesive could be used that could be pressed into the slight space between 100º sheets?

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by Doranwen » 19 Apr 2021, 19:08

cday wrote:
19 Apr 2021, 14:33
I would hold off buying acrylic for the moment until the 90º v 100º issue has been fully finalised, I don't know what general timescale you envison for your brother's visit?
My brother's positive he can figure out how to do a 100° platen; he sounded quite decided on that last I heard. We'll probably just have a few days to work on it - he's coming back for a family event and I'm not sure how much extra time we'll have. No more than a week for sure. But I think this is high on his priority list of projects to do when he's here because he knows no one else in the family will be finishing it for me, lol.

He thought that it wouldn't be too hard to take the acrylic and use a power miter saw to grind off enough to the approximate degree angle to fit the two sheets together, thus allowing them to butt up against each other exactly the way they would if they were 90°. We don't currently have such a saw but we know quite a few people with workshops in the area, and figured we'd put out a notice asking if someone had one and could do that for us or let us come over and use it or whatever.

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by dpc » 20 Apr 2021, 14:50

Can we take it that you have at some point built a scanner with a 100º platen, and if so did you use acrylic or glass?

Yes, I've built scanners with 100 deg. V-shaped platens. I used glass for these. The 0.125" thick glass panes were glued into rabbet joints cut into a birch plywood frame using silicone sealant. A thin bead of clear epoxy was put in the gap on the underside (page side) where the two panes came together along the gutter seam. This was done to offer a bit more rigidity but my main concern was about the sharp edges scraping the paper pages as the platen was worked into the book's gutter. You can also get the glass edges ground to the proper angle where they will fit together in a tight miter joint. I personally never saw the need for that as doing so wouldn't necessarily improve the quality of the scanned page and would likely be expensive. You could do it yourself but be aware that there are safety issues with grinding glass. You don't want that dust blowing around in your workshop (or face!). I recall reading posts here about glass grinding platen edges in the past. Digging those up might be worthwhile.

My experience with acrylic platens has been exclusively with single-page scanners. I quickly discovered that the acrylic attracts paper dust particles that are prevalent in older books. These particles would sometimes show up as a small black dot in image. Back when I was using ScanTailor to post-process my images, it would frequently get confused trying to calculate a content rectangle with artifacts in the images caused by paper specks picked up during the scan process. Those content rects would have to be adjusted manually later which goes against my mantra of doing everything you can in a scanner design to reduce the need for manual hand-holding during post-processing. Another thing that I discovered is that after a while the acrylic surface did get small scratches that would be visible in the images so eventually that required the platen be replaced. The nice thing was that the acrylic sheet is easy to find locally and inexpensive. I eventually just moved to glass panes and stopped using acrylic for anything but prototyping.

As far as working with acrylic sheet, it can be cut cleanly with a rip fence on a table saw and a fine-toothed blade designed for cutting laminates and melamine. You can also cut it with a router, although you'll need a bit with a 40 deg. flute for a miter joint (10 deg. for butt joint like you've drawn) or use a straight cutter with a jig that tilts the router base slightly. There was a comment above about using a power miter saw to do this. I don't see how that would work (I have a Dewalt compound miter saw and it can't cut 12" wide boards), but maybe there's a trick to it that I'm unaware of (or maybe he's referring to a radial arm saw?).

Typically you use something like an epoxy when gluing materials with gaps. From the image that you posted, you could probably go a long way toward closing that gap on that butt joint with just a few minutes with a flat file. At least enough so that you could confidently use the acrylic cement.

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by cday » 20 Apr 2021, 16:15

Doranwen wrote:
19 Apr 2021, 13:58
We'd like to stick with the final design (using brackets/corner pieces to attach) but he thinks he has that sorted out. The challenging part is going to be to get the acrylic edge ground down to the right degree to put together (since they're not going to meet at a 90° angle). He says it needs a power miter saw, which is something I don't know anyone around who has right away; I'll have to ask around and see.
As dpc said in his post above, a power miter saw might not be the best way to profile the two edges to fit together flush: my thought was to use a circular saw, with the acrylic sheet to be profiled clamped down under a piece of board extending close to the edge to be profiled to prevent the acrylic sheet cracking. The circular saw blade would be set just out of the vertical to obtain the calculated profile angle. A circular saw should be easy to borrow, and also probably safer to use. A circular saw blade with a fairly large number of teeth would probably be most suitable, it might even be worth buying an inexpensive one if necessary.

@dpc

100º Platen_2.png
100º Platen_2.png (15.38 KiB) Viewed 681 times

I was interested in your suggestion of clear epoxy as a filler, although you used it on glass: looking at the above image, did you use it to fill the fine gap between the sheets in the left drawing? Or did you just possibly use it to fill the larger gap in the right image?

I had been thinking that positioning the sheets as in the right drawing could be a possibility if the inverted 'v' gap could be filled satisfactorily to a rounded shape. In principle a round acrylic rod of rather greater than 1/8" diameter would fill most of the space, but although one might be available it probably wouldn't be too easy to source unless it were available on eBay. It could avoid the need to miter the acrylic edges especially if finished with epoxy, but is probably a long shot. So miter with a circular saw with a fine-toothed blade?

Edit: Rather than fill the space in the right drawing with a round rod, a 'quarter round' trim could be a better fit, available on eBay U.S. as a hardwood section in 3/16" diameter for example: '3/16" radius Quarter Round Basswood Trim molding'. Just a thought, mitering should be better if it can be done successfully.

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Re: Archivist Quill Kit Plans vs. Archivist Book Scanner Plans?

Post by dpc » 20 Apr 2021, 17:53

Or did you just possibly use it to fill the larger gap in the right image?

Right side.
So miter with a circular saw with a fine-toothed blade?
I haven't cut acrylic with a circular saw, but if I did, I'd look for a blade made for cutting laminate/plastic which is going to have a lot of teeth and a narrow kerf. You'll definitely want to clamp a straight edge to the piece for the saw to cut a straight line. You might have to sandwich the acrylic with some plywood/mdf to prevent tear out chipping. Some test cuts on scrap material of the same thickness as your platen panes may be helpful. You need to be careful that you don't scratch the acrylic when pushing a saw across the surface. Keep the protective paper on the acrylic until you are finished cutting/drilling on it. Double-check that the bottom of the saw doesn't have any metal burrs that could scratch through that protective paper layer. I ended up using a crosscut sled on my table saw when cutting plastic sheet to reduce the chance of scratches.

If you're going to cut acrylic with a saw that allows you to tilt the blade and make mitered cuts, you should just cut both panels with 40 deg edges and glue the mitered joint with acrylic cement. That's going to make a stronger joint than leaving the panes with a 90 deg edge and filling the gap with epoxy (and/or an acrylic rod). I don't know how well epoxy adheres to acrylic. Some experimentation may be necessary. The epoxy that I've used on glass platens was the type used for auto windshield chip repair and is specifically designed for adhering to glass, filling a void, and is clear.

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