Manual Board Slotting Machine

Board slotting is likely the strongest and least invasive method of treating detached boards. Detached boards are the most common point where bookbindings fail. Christopher Clarkson developed the technique in the late 1970’s. The original Peachey Board Slotting Machine, developed in 2005, is used in conservation labs around the world. It is, however, a somewhat large and expensive machine, and best suited for large institutions.

The Manual Peachey Board Slotting Machine is a new affordable alternative for individuals, regional centers, smaller institutional labs and even larger labs with space limitations. This smaller machine can be moved out of the way when not in use, freeing up valuable bench space. It is also simpler to operate.

Manual Board Slotting Machine

The Manual Peachey Board Slotting Machine features stops that automatically guide the positioning of the blade when starting and stopping a cut. In order to make this machine more affordable, three aspects are limited as compared with the original machine: the maximum length that can be slotted is 15″ (rather than 17.75″), the board needs to be manually pulled or cranked using a hand wheel, and the angles for slotting are not infinitely adjustable, but can be set at 11, 13, and 15 degrees. But this is not a major drawback since I use 13 degrees roughly 90% of the time.

Manual Board Slotting Machine

This machine is less intimidating when compared to the original. The orientation of the machine makes it easier to sight the height of the blade relative to the board thickness. The carriage can be rapidly pulled back into starting position after the end of a previous cut. This also makes partial (or biscut) slotting of a board very fast and easy. Overall, the slotting operation seems to be quicker. Many bookbinding and conservation students, such as those from North Bennett Street School, have been trained in the fundamentals of board slotting.  A one to three day workshop on machine operation, basic slotting technique and structures is recommended, though.

Manual Board Slotting Machine


-Width of the machine -12″, Height- 19″, Length- 22″

-Weight 30 lbs. Easy to move and store when not needed.

-Fast and intuitive operation.

-The sliding board carriage can be quickly moved to the starting position at the end of a slot, or between biscuit slots.

-Maximum height of board that can be slotted: 15″

-Dust collector hooks up to a standard vacuum cleaner.

-Thick and thin solid carbide blades included for long cutting life.

-Automatic blade positioning for starting and stopping a cut.

-Boards can be slotted by pulling or cranking.

-Safety guards (not pictured) keep hands away from the blade in use.

-The motor, and other operations are similar to the original machine.

-No electrical transformer needed for international operation, just plug adaptors.

For more information and pricing please contact Jeff Peachey.

Board Slotting Tutorial

August 24, 2011

Safe and successful operation of the Peachey Board Slotting Machine requires a thorough understanding of its components and capabilities. This tutorial is an expansion of a previous blog post documenting the author’s first exposure to board slotting, and attempts to provide a comprehensive description of the setup and operation of the machine. If topics are unclear or absent, please leave a comment or contact the author here. Discussion will begin with instructions for changing the blade, then move to setting the cutting angle and depth, and finish with aspects of the speed of operation. After all of the machine setup is covered, the tutorial will finish with a detailed description of the slotting process. A quick reference guide of all the steps is included at the end of the post for occasional users that need a refresher. You can also reach the quick reference by clicking here.

Part I: Machine Setup

1. Changing the Blade

The literature on board slotting discusses several different approaches to hinge and spine lining construction (Andres, 2008; Peachey, 2006; Zimmern, 2000). Different methods of board attachment can vary the thickness of the hinge material inserted into the board, requiring a matching slot. The Peachey Board Slotting Machine comes with four different blades, ranging in thickness from 0.010” to 0.050”, so that a properly sized slot may be created for the material used. A dial caliper is a useful tool for determining the blade required for a certain thickness of hinge material.

Changing the blade is a simple procedure; however, all safety protocols should be observed when attempting to do so. Ensure that the machine is powered off and unplugged before removing the clear safety guard from the right side of the saw column.

The thumb nuts holding the safety shield can be removed by hand. Grasp the drive wheel at the top of the motor to hold the blade in place while carefully loosening the bolt underneath the blade using the included hex wrench. After removing the hex bolt and saw blade holder, the blade will come free. Exchange blades for one of the desired thickness that is clean and sharp. Ensure that it is in the proper orientation for cutting (illustrated below) when mounting it on the machine.

The new blade should rest flush against the mount. Replace the saw blade holder (flat side down) and hex bolt. Hold the drive wheel to fully tighten the blade with the hex wrench before replacing the safety shield.

2. Adjusting the Carriage Angle

In order for the hinge of the slotted board to function properly, the cut must start just below the top of the board and go to its center.

The depth of the cut may be altered by adjusting the pitch and distance of the carriage relative to the blade. The carriage pitch can range from 0-20 degrees, but the recommended slotting angle for most boards is between 10 and 15 degrees. Thinner boards require a lower angle.

The angle of the platen is adjusted by loosening the black quick-release handle at the left side of the carriage. Angle markings have been engraved into the carriage base to allow for quick and easy setup.

3. Controlling the Depth of Cut

The depth of the saw cut is adjusted by moving the carriage toward the blade using a wheel located at the back of the machine, underneath the carriage.

This wheel is calibrated in 0.001” divisions and one full revolution moves the carriage 0.050”. For most boards, a cutting distance of about 3/16” will suffice. Three full revolutions of the wheel will achieve the recommended cutting depth (0.150” or ~3/16”). This measurement may need to be altered for very thick or thin boards.

4. Setting the Blade Height

The slot begins directly beneath the board covering material, and the wheel at the top of the saw column adjusts the blade height. Like the carriage adjustment, this wheel is calibrated in 0.001” increments, with one full turn raising or lowering the blade by 0.050”. The brass handle further down the column locks the blade position in place. To unlock the height adjustment, the brass handle must be moved to the left.

5. Speed of Operation 

The Peachey Board Slotting Machine features independent saw and carriage speed controls. The saw is equipped with a 0.50 horsepower motor with variable speeds ranging from 70-2800 rpm. The on/off switch and speed control for the saw motor are located at the front of the saw-arm assembly, facing the operator (see above).

The saw speed knob should be set to a 3-4 o’clock position during operation. Cutting at a higher saw speed poses a danger of overheating and burning the board.

A separate controller box operates the carriage direction and variable speed. The toggle switch activates the carriage movement and control direction, while the knob alters the speed. A carriage speed of 2.5 to 3 is recommended to keep the board from overheating.

(NOTE: It is very important to visualize the movement of the carriage before setting it in motion. As the carriage is moving instead of the saw, it is very easy to become confused and send the board slotting in the wrong direction!).

Part II: Description of Operation

Now that the machine is set up and controls have been reviewed, the machine is ready for use. The book board is placed with the outside of the board face-up in the carriage and centered under the clamping bar. Ensure that the spine edge of the board is flush with the edge of the carriage. If the board covering material may be damaged by the tension bar, a scrap piece of binder board cut to the same dimensions as the book board may be placed between the tension bar and board. Tighten the bolts on the tension bar simultaneously and evenly in order to achieve uniform tension on the board, much like tightening a lying press. Uneven tension may adversely affect the saw cut, damaging the book board.

The height of the blade is set to just under the board covering material (0.040″ – 0.080″ below the top of the board). It is important to check the alignment of the blade at both ends of the board before slotting. To do this, move the carriage so that the blade is at the tail end of the book board. Bring the carriage toward the blade until the saw teeth are just against the board edge. Flip the brass lever at the front of the saw column to the left, and move the blade to the correct height.

Peachey (2006) describes three methods for aligning the blade to just under the covering material (p. 31). If the placement of the blade cannot be accomplished by eye, a scalpel may be used as a gauge. Simply press the tip of a scalpel blade into the spine surface of the board at the intended position of the slot and raise the blade until it rests against the flat of the scalpel.

One may also calculate the appropriate blade height. Using a caliper, measure the thickness of the board and set the blade height through the divisions on the adjustment wheel (marked in 0.001” intervals).

When the blade height is properly set at the tail of the board, lock the blade position by flipping the brass lever to the right. Back the carriage away from the blade, then move the carriage to the right so that the head of the board is at the blade. Once again, adjust the carriage depth so that the teeth of the blade are just against the board edge and examine the alignment. If the blade position is the same at each end of the board, the slot may be cut. Some boards may be warped or distorted so that the same blade height will not slot evenly across. If this is the case, adjust the blade height to compensate and recheck the alignment.

The slot is always cut from the head of the board to the tail, or with the carriage direction opposite that of the saw. Not only does this produce a straighter cut, but most of the board debris is expelled by the motion of the saw (Peachey, 2006, p. 30).

One will start and stop the cutting of the blade in different locations on the board, depending upon the method of board attachment. For example, Peachey (2006) describes a method of “biscuit slotting” for tight backs in which the board is only slotted at the head and tail spine panels (p. 30). Andres (2008) describes a repair structure in which the boards are slotted all the way through the turn-in material (p. 24). It is also often easier to slot  through the length of the board if the initial cut was in the wrong position, the boards have extreme backcornering, or the covering material is abraded.  Most instances, however, will require a slot that begins just inside the head edge of the board and continues along the length to just inside the tail edge (illustrated below).

With the carriage position set at the head of the board, start the blade motor and check the motor speed. At this time, the vacuum is started. Adjust the carriage depth until the blade begins to make contact with the board edge, then set the cutting depth by turning the wheel three full revolutions. Flip the carriage control toggle to the left and turn the carriage speed up to 2.5.

Closely monitor the progress of the slotting operation. If burning occurs, the blade or carriage speed should be reduced. If burning persists, the blade may need to be cleaned or sharpened. When the blade gets close to the tail edge of the board, slow the carriage motion until it reaches the appropriate position. Stop the carriage motion by turning the knob down to zero and flipping the toggle to the center. Back the carriage away from the blade and turn off the saw motor. Finally, switch off the vacuum and loosen the tension bar. Remove the book board from the platen and gently tap the spine edge of the board against a hard surface to clear any sawdust. A micro spatula may also be used to clear the slot.

Part III: Quick Reference Guide

  1. Determine the appropriate blade thickness and change the blade (if required).
  2. Set the carriage angle.
  3. Place the board in the carriage.
  4. Move the carriage to the tail of the book and adjust the blade height.
  5. Move the carriage to head of the board and check the blade height.
  6. Start the saw blade with the speed dial set to 3 or 4 o’clock.
  7. Turn on the vacuum.
  8. Move the carriage up to the blade, then turn the wheel three revolutions to achieve the right depth.
  9. Flip the carriage toggle switch to the left and begin the carriage motion (at a speed of 2.5 or 3).
  10. When the board has reached the desired endpoint, stop the carriage.
  11. Back the carriage off of the blade.
  12. Turn off the saw motor.
  13. Turn off the vaccum.
  14. Remove the board from the machine and gently tap the spine edge to knock out any debris.


Andres, A. M. (2008). A new variation on board slotting: Case binding meets in-boards binding. The Bonefolder: an e-journal for the bookbinder and book artist, 4(2), 24-26.

Peachey, J. S. (2006). New possibilities for board slotting. The Bonefolder: an e-journal for the bookbinder and book artist, 2(2), 28-32.

Zimmern, F. (2000). Board slotting: A machine-supported book conservation method. The Book and Paper Group Annual, 19, 19-25.

Jeff’s post about slotting Plexiglas led me to the thought that board slotting may be a useful technique for creating clear-spined drop-spine boxes. A clear spine is advantageous in many ways. Libraries which function as museums might keep as much of the aesthetic of spines as possible while still completely enclosing the book in a hard box. Labeling is still possible if necessary but may be skipped entirely if the spine of the book is already labeled. The visibility of the spine acts against loss or theft, since one can see at a glance whether the box is full or not. Finally, the rest of the box still being constructed in cloth over board allows it both to breathe and absorb water (rather than the book absorbing water) should there be a leak or spill nearby.

The constructions I have seen involve making a thin card frame instead of the usual board spine piece, both on the inside and the outside, and covering it in cloth as part of the casemaking process. This frame needs to be minimally larger on the outside than the inside to avoid seeing the seams through the acrylic, and given that it is glued to either side of the acrylic, the raised edge is vulnerable to lifting either on its own or as people pull it from the shelf. It’s not an incredible problem, but it would be nicer to have something a little cleaner and faster to make.

Poly(methyl methacrylate) (PMMA–trade names Plexiglas, Perspex, etc.–because I don’t actually know what brand mine was, and to avoid the different UK/US standards, I’ll just refer to it as PMMA) comes in a sheet that is relatively easy to score and snap with a utility knife and a ruler. It can be manufactured with a UV coating, so in storage situations where light exposure is an issue, the longer wavelengths might be at least minimized while still maintaining a clear spine. And as Jeff mentioned, it does come with various degrees of resistance to abrasion, reflection, etc., so different budgets may be able to afford different grades of  PMMA, depending on the library’s priorities.

It wasn’t a huge thrill to slot; I found I had to go incredibly slow to avoid melting the PMMA with the warmth of the blade, and because everything is visible the slot needs to be perfectly even in order to not be visually distracting in the end. The blade needs to be exactly the thickness of the cloth to be inserted, because unlike board, the PMMA is inflexible (or at least not flexible enough to ease open the slot without serious risk of snapping the thin side right off, as I discovered…). And the dust inside, which is partially stuck to the slot from heat, needs to be cleared out thoroughly before the cloth can be inserted. But it does work! You’ll have to forgive the unusual cloth color for a box; it’s all I had around at the time.

A few notes:

Adhesives: EVA (ethylvinyl acetate) does hold up to a point, and I assume PVA (polyvinyl acetate) would do the same but didn’t try. Paraloid B72 is the best option: when subjected to tensometer testing, the cloth tore before the joint failed. I applied the adhesive using a syringe, and found no difference in strength when the Paraloid was laid down along the inside end of the slot but not completely covering the sides. (More on that later).

The samples above show the results of testing on the tensometer. Quantitative results didn’t seem terribly useful, although I have the figures if anyone is interested; really the test of the join needs to be that it doesn’t fail before the cloth, which is what would fail normally. If one wanted to be completely thorough there ought to be a fold test to see whether the hard edge of the PMMA causes earlier fail of the joint, but for now I just tested to make sure the adhesive would stand up to the stress of even a very heavy box. The EVA sample at top is representative of all the EVA samples; there would be some amount of distortion of the cloth before it pulled out of the slot relatively neatly. The two Paraloid samples show that occasionally the fabric would begin to pull out of the slot but this was almost simultaneous with the tearing of the cloth, so it didn’t cause very much concern.

Labeling: I stamped the PMMA with various gold foils on a PräGnant at 85 degrees F with relative ease. It wants relatively light pressure and no dwell. I haven’t tried letters larger than 14 point so I don’t know if it gets more difficult at larger sizes.

More images of the testing and prototype box are here. When I get some diagrams together I’ll post again with the procedure.

The one thing that has me stumped is that the cloth absorbs the Paraloid completely in some places and not as much in others, and the cloth is much darker where wetted with Paraloid. Introducing enough adhesive in the slot to completely cover the cloth leads to too much seepage once the cloth flange is inserted, which is even more unsightly. I tried sanding the PMMA from the outside just over the slot hoping to fog the material enough that the area would be opaque, but there just isn’t enough distance from the cloth in the slot to obscure it completely and it ends up looking messier. Any thoughts?

I’ve become aware of a very thin 100% cotton available in 19 colors.  It is made by Swiss company  Creation Baumann, called Balloon Plus 415, and distributed worldwide.  According to Testfabrics, the US distributor,  this line is dyed with reactive dyes.  I’ve experimented a bit with it, and like most airplane cottons it should be washed before use. It is 73 g/m(2) and is an astounding .oo5 inch thick– the airplane cotton I have averages .008 inch.  Creation Baumann also makes a 100% linen called Loris 173, which is thicker at 187 g/m(2) and around .010 inch.  It is made in 12 colors.  Both can be manufactured to custom colors, if you happen to need 260 yards.

The only downside are the available colors, which are more oriented for designers rather than books, but the medium brown seems quite useful.  I can imagine these fabrics being used on their own, or as a base for additional toning, which I haven’t tried yet.  They also seem useful for other types of board attachment, rebacking, etc. when a thin, strong, natural fiber is desired.

Puck lights are small battery powered LED lights, usually with five LED’s, usually used for quick installation in closets, under kitchen counters, etc.  I assume the name comes from the fact that they look a bit like a hockey puck.  They are a very useful lighting option for board slotting machines- Mindy Dubansky from the Met, investigated lighting for her slotting machine, and a lighting expert suggested this solution.  It is a bit counterintuitive, lighting from below to see the board edge on the top of the blade, but in practice it works great.

I was talking to a colleague recently who was convinced that board slotting, because it removes a small amount of original material from the interior of the board, was a treatment they would not perform. They insisted that the removal of original material was never acceptable.  The primary issue– when is the removal of original material ever  justified– is  important and worthy of discussion, especially when balanced against other treatments that may obscure information about a book’s construction and its aesthetics.

Obviously, no conservator condones the removal of original material.  However, when the amount removed is quite small, and it is from an interior area, I feel it has to be balanced against the types of information that can be obscured or changed during the course of a treatment that does not remove original material.

Specifically, I am thinking about the joint area of the book board.  This is a critical area of a book structure, and both the pastedowns and covering material contain and extraordinary amount of information about how the endsheets were put down, bumps from spine linings extending onto the boards, lacing patterns, and sometimes even strike-through from brush marks.  Traditional methods of board attachment often obscure, if not obliterate this type of information.  And any suspected alteration often raises questions for future historians.

Since the majority of prime candidates for board slotting tend to be 19th century books– a time period when the introduction of machinery and other productions oriented techniques– the speed and accuracy in which the binders worked, in a production setting, are important aspects of these books.  And for books that posses high aesthetic values, slotting certainly preserves the original appearance better than most (all?) other board attachment treatments.

Thoughts, anyone?



September 19, 2010

I have recently dyed more aerocotton for slotting using Procion MX reactive dye, the previous stocks from my initial experimentation with dye recipes having now run low.  The pipette filler I mentioned in the original dye post has been of great benefit for measuring out the very small and precise quantities of stock solution required for accuracy in the dye recipes.  There are many on the market with huge variation in sophistication and price, but the simple one I’ve been using seems fine.  The wheel mechanism allows very accurate measurement and it is easy and quick to empty.  Although we ordered our filler from Fisher Scientific you can see an image at the following link:

I’ve also experimented with an easier way to dissolve the Glaubers salt (sodium sulfate) in the dye bath.  As it is anhydrous it has a tendency to clump together when added too rapidly to the solution and the resulting rock like particles are very difficult to dissolve.  It is essential to have the salt fully dissolved to prevent the resulting dyed fabric from being uneven, or unlevel, in colour.  Previously I have gradually scattered the salt over the surface in small quantities, vigorously agitating the bath throughout.  This time I tried to pre-dissolve the  salt in a moderate amount of cold water from the total quantity of water used in the dyeing process.  Using water from the overall quantity required is important as the success of the dyeing is regulated by the amount of water to weight of textile ratio and adding additional water would alter the end colour.  However, it was not possible to dissolve the quantity of salt necessary without using a larger quantity of water than the 50mls I took out of the dye bath, and any more would prevent the first stage of the dye process from effectively taking place, that is the wetting out of the textile in the dissolved dye.  Heating the solution is probably the answer – I’ll try this and let you know if this has any effect, good or bad!


More on Syringes

May 26, 2010

I noticed that McMaster-Carr sells syringes and needles in the United States. They are currently  available in type 304 stainless steel. Gauge 25, .020″ O.D. fits a 1/64″ blade quite well, $13.97 for 50.  The 21 Gauge, .032″  O.D. fits the thicker 1/32″ blade, also $13.97 for 50.  Both are an easy to handle 1/2″ length.

As Victoria previously mentioned, there are advantage to flexible plastic needles as well.  The thinnest PTFE needle they sell is 22 Gauge, .040″ O.D., $19.43 for 10. They also have a Polypropylene needles, 25 Gauge with a .029″ O.D. for $2.23 each.

WARNING: Their catalog contains over 480,000 products and is highly addictive.


Visible Board Slotting

January 5, 2010

Recently, as I was installing a board slotting machine, several of us started talking about the possibility of slotting other materials.  The blades that the machine uses were originally designed to cut metal, and I’ve successfully slotted wood for an artist book edition. Plexiglas, aka. Perspex, was a natural choice, given its use in mounting applications The ability to insert an flexible hinge into a piece of it seemed to be potentially useful for something, although I’m not sure exactly what.  Normal plexiglas slotted fairly well, with a fairly even matt appearance in the actual slot, but cast plexiglas, which is optically slightly clearer, didn’t slot as evenly, and tended to clog in the slot itself.  Reversing the direction of the blade, in order to clear the slot, exasperated the problem even more.

I haven’t tried the new Optium (TM) from Tru Vue, which according to the manufacturer, has less than 1% reflection at a 90 degree viewing angle, dissipates 2000 times more static charge than normal acrylic, passes a 600 dry cloth rub test (at 2.5 pounds) for abrasion resistance, 99.6% UV filtering below 380 nm and 98% light transmission.  At least they send out an impressive looking sample set!

Since the exact path of the blade is visible, a slotted piece of plexi is a useful teaching tool when beginning to learn board slotting.  It helps the uninitiated visualize where to begin the slot relative to the height of the board.  The dust tended to clump together, so a thin, rigid piece of paper was used to clear the slot.

If nothing else, this visible slot is a very clear example of the precision and angle that is usually hidden.


Daubeny Project: Light Relief

November 19, 2009

The last few weeks has seen me concentrating on the big questions of light and consolidation.

The Daubeny Library both benefits and suffers from being in its original laboratory setting. The context is wonderful and really adds to the uniqueness of the collection, but the light exposure it suffers from several 3 metre+ high windows which face the book presses is less great. I have been logging light levels over a number of months, as well as setting up a long term light test using samples of the dyed textile used for slotting. Light levels have become somewhat of an obsession due to the work I did on the reactive dyes, as traditionally, and somewhat unfairly, they have always had a reputation of being less light fast than direct dyes. At Daubeny, the UV light levels are encouraging but the visible light levels are slightly too high. It is a difficult space to regulate in light terms as it is used both as a library and a lecture room. Consequently I have been encouraging users to lower the blinds in the room after use, but this has had a variable degree of success. However, any lowering of light levels is a big improvement on the relatively uncontrolled exposure the collection has experienced up until the recent refurbishment of the laboratory.

Consolidation in progress. Image reproduced with the kind permission of the President and Fellows of Magdalen College, Oxford.

The chemically degraded nature of the majority of the leather covering the Daubeny books has also been a challenge. Early tests with the traditional consolidant mixture of klucel g in IMS showed considerable and unacceptable darkening of the leather, and a coarsening of the leather surface. Having done some research into the water content of common solvents, I settled on isopropanol as the solvent of choice. Unlike IMS, with a water content of up to 1%, isopropanol has a water content of less than 1%, and as such seemed a better bet not to darken the leather. I made a 2% solution in isopropanol by gradually adding the solvent to the klucel g, stirring all the time, and leaving it to fully dissolve overnight. This resulted in a very smooth, gelatinous liquid which when applied with a brush caused neither darkening nor streaks across the leather surface.

Victoria (Stevens)