A New Tiller Design - The Offset Tiller

[Dennis La Varenne]

In order to get around the long recognised problem of the effects of the diagonally applied drawing force on a bow, I have designed and built a new tiller described below which I have called the ‘OFFSET TILLER’, the schematics of which I have added below (1 and 2) showing the design of the tiller itself and another of how it looks with a drawn bow mounted, as well as the photographs (3, 4 and 5) showing the finished tiller from different angles.

To date, I have not seen anywhere or ever heard of it being made anywhere else, although this idea has been fermenting in my head for some years now. When I look at it now that it is made, it seems to me to be so obvious a solution to an old problem that I wonder that it was not done earlier.

Its invention arose following the many discussions/requests on this site in regard to correct tillering method and the problems involved with tillering the universal bow configuration where the pivot/balance point on the handle of the bow is below the line of the arrow or drawing line.

This ‘normal’ design has the inherent problem of an unequal distribution of drawing pressure on each of the limbs which, if it is not gotten right, results in dis-synchrony of the limbs during the draw and power strokes affecting arrow flight, causing inefficient use of stored energy and felt handshock, and sometimes, limbs permanently going out of tiller with each other.

Various people have relied upon the techniques of tillering bows by placing the tiller as near as possible to the arrow pass or having a tiller with a very wide cradle – in some cases nearly the full width of the handle – in order to attempt a compensation for the line of drawing force from the arrow pass to the string. Most simply put the tiller in the middle of the grip and tillered the limbs with either positive tiller (slightly weaker upper limb) or negative tiller (slightly weaker lower limb), or even no tiller at all – simply letting wood bows self-tiller from shooting, which wood bows will do without damage as I have found to my surprise.

There are two main schools of tillering theory – Positive Tiller theory which postulates that in all bows of any configuration/combination of limb lengths, the upper limb must be slightly weaker to compensate for the effects of the diagonally applied line of drawing force, and Negative Tiller theory which postulates the opposite – that it is the lower limb which must be made slightly weaker at least in bows of equal length limbs.

The offset tiller comprises two parts – the cradle with its jaw to hold the bow, and the tiller itself, along which the tillering string is drawn in order to show variations in or symmetry of the bending limbs of the bow as it is trained to bend. Bolts join the two components laterally and the distance between the centres of both are varied by the use of spacers between them. In my final version, I have used washers (see diagram and pictures). I have designed the jaw of the cradle to be wedge shaped in order to allow the bow to rotate on its long axis so the string maintains its correct alignment with the centreline of the bow during the tillering process.

The offset tiller has the capability of being infinitely adjustable for variations in the distance between the arrow shelf/pass and the pivot point of the grip which, excluding some kind of anatomical problem, is usually in the middle of the grip area and in line with the radius bone of the forearm. This line is common to all bow handle designs from ‘low wrist’ grip on the straight handle designs to the forward sloping ‘high wrist’ designs. The only difference between these ends of the range is the vertical distance between the arrow pass and the pivot point of the grip. The offset tiller is adjustable for this variation and it is simple to make from commonly available hardware suppliers timber and a couple of large diameter bolts, nuts and washers.

An important point which it demonstrated to me during testing is the significance of knowing the width of the bowhand of the intended user. This impacts greatly on how the bow balances during the draw. This hand width is that measured horizontally across from the lower knuckle of the thumb where it joins the hand, straight across to the outside edge of the hand below the little finger (see pic 6).

It is preferable that the length of the handle closely matches that of the hand width of the user. Matching these two widths puts the pivot point in the middle of the handle in line with the radius bone, particularly on bows with straight handles. A line through the radius bone extends to the base of the thenar prominence, or ball of muscle at the base of the thumb where a straight handled bow balances.

A large hand on a shorter grip will adversely affect the dynamic tiller of a bow, or the ability of both limbs to move backward and forward simultaneously during shooting.

The larger hand forces the bow to balance below the middle of the short-handled bow tillered to balance in the middle of the short handle. This widens the angle of drawing force and pushes a heavier bend into the lower limb and a lesser bend into the upper limb causing uneven pressure on the limbs (see pic 7). Uneven pressure on the limbs upsets limb timing with possible long-term changes to the tiller of a wooden bow. My offset tiller showed this phenomenon quite emphatically in pics 7 and 8. Pic 8 shows the same bow balanced in the middle of the 4 inch grip as would be held by a person with a 4 inch hand.

Using my offset tiller, there is nothing to stop a bow with a short handle being correctly tillered for a person with a large hand so long as the hand width of the shooter is known and the cradle is placed on the handle at the proper position appropriate to the hand width.

With sloping (high wrist) handles, this is not so critical because the line of the radius bone moves closer to the line of arrow decreasing the angle of drawing force and reducing its effect on limb timing and tiller.

What did surprise me was that the amount of tiller required in a bow was less than I had previously believed, particularly in bows with even length limbs – less than 2mm. Up to 3 mm was enough for a person with a hand of 5 inches across. For asymmetric bows, it was even less, or none at all because these bows have less difficulty with limb timing because of the greater length of the upper limb.

In the accompanying pictures, you will observe that there are centre lines drawn on both the cradle and the tiller. These are alignment lines and intended to align with the middle of the grip where the bow will balance and the centre line of the arrow. Altering the spacer width allows this gap to be varied to match the handwidth and thus hand position of the user on the grip.

During tillering operations using this tiller for a Mediterranean loose, from brace height onwards, the string should be marked at that point where the arrow would normally nock with the arrow at 90 degrees to the string at the arrowpass or shelf. This mark on the tillering string should always be kept centred in the middle of the tiller throughout the tillering operation as you can see in pics 7 and 8. The tiller itself is nearly as wide as and suitable for the Mediterranean loose of one finger above and two below the arrow.

For a 3-under loose, the outside edge of the tiller is lined up to the centreline of the arrow by reducing the amount of spacer material.

The offset tiller has demonstrated to me during testing of existing bows in my possession that for accurate tillering of all bows, the width of the hand of the intended user be known, especially those bows with a straight handle, whatever the limb length combination/configuration.

Even a small difference in hand width (meaning a change in drawing force angle) significantly changes the shape of the bends of either limb and their symmetry. With their less elastic limb material, this has important implications for the stability of the tiller of wood bows in the longer term.

The cradle on the offset tiller shown is 32mm wide. I would not advise going any wider for two reasons; the first being that a wider cradle means lower spacer adjustment range, and secondly that a wider cradle stops the bow from balancing naturally while it is being tillered. I recommend on the other hand, that the tiller itself be left wide to approximate the width of the drawing fingers on the string, but is not so important with the cradle which can be quite narrow, since it only balances the bow.

Initially, when you begin tillering, the bow will want to swivel to the right, but as you tiller your bow, you will find that it no longer swivels as it begins to balance on the cradle. Both limb tips must come back on the same plane, parallelling the long axis of the bow, which should be at 90 degrees to the tiller. It will become quickly obvious what you need to do to get your bow to balance on the cradle with these two fundamental angles (the long axis of the bow at 90 degrees to the tiller) correct.

Those of you using wall mounted tillers with pulleys and cables can rig them up following the same offsetting principles, while those using a conventional tiller stick can just add the offset cradle without other alterations.

For what it is worth, I have observed that there is a relationship between the upper and lower string angles of the drawn bow and the angle of drawing force. Depending upon how well you do your tillering, when the distances between the long axis of the bow and the limb tips (Y) are equal, if you subtract the angle of the lower string (A) from that of the upper string angle (B), you get the angle of drawing force (C) in the diagram (9) below.

[ed]

Interesting. I have large hands but don't heel my palm to the handle but instead have the lower two fingers away from the handle and only hold with the top two fingers. I would expect then the forces to be the same as a person with a very small hand.

If the forces result in such small differences in tiller then are we not making up for it by playing with the arrow knocking point to get good flight. Surely when the arrow flys out of the bow without any up down porpoising then we have the limbs in synchrony due to affecting the tiller at the time of draw.

[Dennis La Varenne]

Ed,

Try making a bow using this tiller, and let me know your results. If you are happy with the performance of your bows as they are, don't worry about it.

Dennis La Varenne

[Paul]

I know of a few bowyers who have used this offset tillering stick before Dennis including Dean Torges who was an advocate of the method for a while and I'm sure that there are quite a few others that I don't know about that have used it as well.
I actually used to tiller my selfbows with a very similar tiller stick a few years ago untill I began using something like the one seen here: http://www.bowyersedge.com/ABC_06fin.html The bow handle is placed upon a radiused shoulder on the tillering tree slightly below the arrow rest, the point at which you want to make the dynamic fulcrum, and pulled from the position of the middle finger on the bowstring. I believe this method assists in making a better balanced bow than any other method I've tried so far.

[Mick Smith]

Dennis

It's an interesting concept. Correct me if I'm wrong, but I feel your design would be perfect if one used a release aid when shooting the bow, as the drawing of the bow and the forces applied to the released arrow would all be consistent and in-line, as the release aid is attached to the string in perfect alignment with arrow.

However, as we all know, we traditional archers use our fingers to draw the bow, either the typical Mediterranean release or three fingers under. The string is drawn by the fingers and the fingers are pulling from a point on the string which is below the arrow. Shouldn't a bow be tillered to suit the placement of the drawing fingers rather than the position on the arrow on the rest?

Everytime when I order a custom bow, I'm asked the question, "do you shoot with split fingers or three under?" I've always presumed the reason for this question was so that the bow could be tillered to suit the positioning of the drawing fingers on the string.

I can see obvious benefits in your tillering design once the arrow has been released, but what sort of negative aspects would your concept have in the moments before and during the actual release? I imagine the bottom limb will have additional stresses and the upper limb would have lesser stresses placed upon it, would this effect the bow's performance? Wouldn't it increase the likelyhood of erratic performance?

Don't get me wrong, I'm not knocking your concept. I'm not really qualified to do that, as I don't have any experience in making bows, having never actually made a real bow. I'm just a little confused. I'm also sure you will have a rational explanation.

Mick

[Steven J]

Dennis,

I am looking forward to your first book on the mechanics of archey

It is interesting to note that your tiller on even limb length bows is as low as 2mm. Since making bows, I have also found that tiller differences required are similarly very low. I have often wondered if it is really worth tillering a bow differently for a split fingered shooter or a three under (like myself). A small movement of the nocking point seems to have as much impact as changing the tiller. 3mm is the standard tiller I would give to a longbow if I was unsure of the final archer.

As you suggested in another post, my starting point for the position of the nocking point is to place is according to the difference of tiller as measured from the bow. This is a rule that has worked for me so far.

Many thanks for the time taken in providing us with such clear diagrams.

Steve

[yeoman]

Mick,

While your comments do hold some merit, they are also applicable to almost every other single tillering device in the whole world.

I saw this the other day 'in the flesh', and I must say that I'll now be making one for myself. The fact that someone else has thought of it before should not detract from the achievement of Dennis conceiving of it on his own, methinks.

Jeff is right...if you're happy with your bows with the method you're already using, then there's no need to try this. However, if you want to try something different, give it a go.

Dave

[Dennis La Varenne]

For everybody,

This reply will be a bit longish, but just to make sure everyone understands my terminology below, I use the traditional word in the following ways – the noun ‘Tiller’ to describe the instrument bowyers have traditionally used to control the bending shape of a bow’s limbs which I capitalise (German fashion) for expedience.

I use the active verb form ‘to tiller’ in its traditional usage to mean inducing the optimum bending shape into a bow’s limbs. The adverbial phrase form ‘in/out of tiller’ is used to refer to the condition of a bow’s limbs; the adverb ‘tillered’ to refer to the state of tiller of a bow, and the prefix ‘tillering-’ for any tool used for the purpose/process of Tillering (noun).

A Tiller has a ‘cradle’ or a ‘jaw’, into which a bow is cradled. It has nocks into which the tillering-string is nocked during the process of Tillering to ensure a well-tillered bow.

Thus, I use a Tiller and tillering-string to tiller a bow by cradling it in its cradle/jaw to bring its limbs into tiller by the technique of Tillering.

I don’t use a tiller tree or tiller stick even though I have used both those terms in the past to try to avoid confusing the various usages of the word.

Paul first,
I had a look at Dean’s site via your link and his setup is not the same as mine. It is the conventional in-line Tiller setup where the place from which the string is drawn is directly in line with the cradle.

To balance this bow, he changes the physical position of the bow on the cradle so that its mass is distributed evenly on either side, and then draws the bow from that position.

Look at his picture 3 and compare it to the picture next to it (4) where the bow is ‘balanced’. It is a completely different setup to mine.

Dean went to lengths in his book, Hunting the Osage Bow on how to position a conventional in-line Tiller. This kind of Tiller has long-standing inherent shortcomings which bowyers have tried to circumvent by various repositionings of the in-line tiller along the grip. All have the problem of not being able to allow for the differing angles of drawing force created from low- to high wrist grips and the varying widths of hand encountered.

The in-line Tiller tries to be the one size that fits all which it cannot. Most long-term bowyers are aware of this and had a bit of a fiddle with shifting Tiller placement at some time in their history. It has served very well for centuries, even perhaps millennia and is not to be discarded lightly or without good reason, or even discarded at all. It is better suited to tillering a bow for a high-wrist grip where the angle of drawing force is quite narrow and small variations have less impact upon the vertical alignment of the tips during the draw\power stroke (see Ed’s comment above).

My tiller was designed to get as many variables of tillering as possible out of the process from the outset by approximating as nearly as possible the relative positions of the hand on the grip and the bowstring during the draw – and by being adaptable to best effect to the widest range of hand widths/drawing angle applications.

The same offset setup via a pulley system on a wall would be even better.

It is also a very useful investigative tool in working out why bows want to bend in certain ways and the consequences in the long term and short term if I need.

Dean’s test by the way, is a very good rigorous test against how well a (wood) bow is made and stand up to field use. Many of us carry our wood bows like newborn babies rather than tools.

Mick,
If you read back over the post, you will see that I recommend the Tiller to be wide to approximate as nearly as possible the spread of the fingers on the bowstring. It is not perfect at 32mm, but much improved on the narrow Tillers commonly used. Your release-aid simile doesn’t really apply here. None of us uses a finger draw of any kind which replicates the release-aid loose because of the spread of fingers on the string which my Offset Tiller attempts to address. Why the tiller-nocks were so wide was to get around just the issue you are bringing up.

The Tiller is the universal tool of bowyers for carefully bringing both limbs into correct timing by matching their bends to each other in a specific relationship so that both limbs travel backwards and forwards at exactly the same time. In the case of bows of European/American origins, to have the upper and lower limb tips travel together on the same vertical plane (within a very small margin) throughout the draw/power stroke. (Extreme asymmetrical bows are under investigation.)

When next you get your bow out, draw it Mediterranean style and increase-decrease the pressure of your ring finger on the string and see the effect it has on the string and the limb tips, then take it completely off the string and see what happens. A lot more of the drawing load comes onto the ring finger than most of us realise. The full amount of drawing finger contact has a lot of bearing on the string angles between upper and lower limbs, and the angle of the line of drawing force. Using this Tiller, you can make allowance for these differences.

When the limbs bend differently by changing the drawing (fingers) pressure for any reason, the string angles change in relation to the angle of drawing force. On a wood bow, this has even greater impacts on the symmetry of the bends in the bow’s limbs, their power stroke timing and the potential for long-term changes in tiller - good or adverse.

A small change in the angle of drawing force has bigger changes in the drawn limb shape and relationship between upper and lower tip positions at full draw. That has implications for the timing of the limbs during the power stroke depending upon how much vertical mis-alignment there is at full draw. You can see these changes take place on this Tiller when you simply shift the position of the string by as little as 1mm toward the upper or lower tips. The bow rocks in the cradle and the shape of the curves of the limbs changes a lot.

Happily for those of you who shoot with a fairly high wrist grip where the line of the radius bone is much closer to the lie of the arrow, your angle of drawing force is much smaller. The limbs do not go out of timing with one another nearly as much or as severely as those of the rest of us with low wrist grips on vertical handles.

During the old pre-WWII target shooting days for instance, where all the bows used were straight gripped, the shooters used to go to a lot of trouble to train themselves to have as little contact between the grip hand and the bow as possible. Where possible, they used as high wrist a grip as they could, much like Ed describes above. Many didn’t off course. But my offset tiller can produce a bow specifically designed for even this small angle of drawing force from the outset of building.

At some point, using a high wrist grip, as Ed suggests, this angle will become so small that merely shifting the nock point on the string slightly will have all the necessary corrective effect one needs. However, for those who use a low wrist grip, particularly those with hands wider than 4 inches (or any hand size for that matter), a bow can be made right from the outset without fiddling to fit afterwards.

StevenJ,
The conventional technique is to zero-tiller for a 3-under loose and 2-3mm for a Mediterranean loose. The reason we do this is because the conventional in-line tiller cannot cope with any angle of drawing force because it is in-line. So, we compromise with a positive tiller of 2-3mm as you use.

The real problem arises when users of different hand widths use a bow of pre-determined and set handgrip length. The ‘standard’ tiller doesn’t work as well as it should and we try things like moving the nock point up and down to try to correct things like varying amounts of arrow porpoising in bad cases.

This Tiller is my attempt to get around the problems of a rigid handle bow with same- or nearly same length limbs where the vertical distance from the line of the arrow (the working centre) is greater below than above, effectively creating one shorter and one longer limb.

The conventional in-line Tiller is best suited to bows of same length limbs like the ELB, which do not have a defined grip and where it is usually gripped almost at or just below centre and the correct balance point for the individual is found by ‘feel’. The grip position on this kind of bow has a very slight forward lean, which angle seems to need to remain the same (I haven’t measured it accurately yet) throughout the draw/power stroke whilst the tips travel on the same vertical plane. This slight forward lean, like the high wrist recurves, produces a smaller draw force angle than a straight vertical grip, and the amount of after-tillering tinkering with the nock point position is minimal.

I hope that addresses your questions and those of you who like building bows, give it a tryout and keep in touch. I really do need others to try it out to see if my observations and conclusions from my own testing bear out.

Dennis La Varenne

[ed]

Thanks Dennis, that cleared a few things up for me.

I liked from the outset the wide string nocks on your tiller or tillering-stick, thingamajig.
Just to clarify one other point then, when you tiller the bow do you mark on the string where you would normally knock your arrow and then reference it to your tiller's string knocks? Reason I ask is you comment that shifting the string a little either way makes a big difference to the apparent tiller of the bow when drawn. It would seem the logical conclusion to your comment and I think I will start to do just that myself now.

[Glenn Newell]

Dean Torges does not use an inline tiller at all. Deans places the bow in a cradle which is the same dimension as the bow hand and then draws the bow down from exactly where the the bow would be drawn from. The draw hook is the same dimensions as if you are drawing with split fingers. This is the only way you can see the true tiller of a bow. Inline tiller sticks are deceptive and a waste of time. Offset tillers are nothing new. Plenty of bowyers have used this system for many years, what would be the point tillering a bow anyother way...Glenn...

[Dennis La Varenne]

Ed,

When I set the stave in the cradle, I make sure it is at 90 degrees to the tiller, then mark the low braced string on the same line the arrow would lie - the same line as the middle of the tiller.

Using this kind of tiller, you must start with a braceable stave.

I start bringing the limbs back watching closely that both limbs come back at the same time and through the same horizontal plane. Naturally, the bends must be good as usual.

As you've realised, moving the string laterally while on the tiller changes the shape of the bends of the limbs as well as the alignment of the tips by quite a lot.

Any finetuning of the shooting position of the arrow on the string can be done last after some shooting in because the limbs will still change shape a little from actual shooting. Those changes can be final corrected by shifting the nock point on the string to finalise things when the bow settles down.

Glenn,

Thanks for pointing that out to me about Dean's tiller. It is not at all evident on the URL above, which is a completely different instrument altogether. I went and hunted up an old copy of Hunting the Osage Bow and there it is on pages 111 and 112, just as you explain. That was a serious misreading of HOB on my part. I should have re-read the section in book before I made my comment above rather than rely on memory.

I am not the only one to invent this design. Dean's, mine (and yours???) are the only versions that I have ever heard of so far. Two days ago, I believed mine was the only one.

Dean's is the better design as a pulley operated vertical system. I said as much about this kind of design above. In fact, now that I have re-examined it, if it was adjustable for the hand pressure point on the grip it would be pretty much the ultimate tiller.

Mine has the benefit of being adjustable for the actual balance point of the hand on the grip in relation to the line of the arrow irrespective of how long the handle or the person's hand is, but lacks the pulley system.

And yes, knowing what I now do, why would anyone want to use an in-line tiller.

Regards,

Dennis La Varenne

[Glenn Newell]

I have spent a total of 5 months in the USA on two different trips sourcing out the as many different bowyers as I could in that time and I was explained the offset tiller back in 1994. Up until then I used in line tiller boards because that is what some of the best text books said to do, that's why I have said in the past that information contained in some text books on bow building is flawed.
You should never take antibody's word for it that what they say is correct. Offset tiller has been used since the 1930's as far as I know. The offset tiller system is the best way to see true tiller of a bows limbs through the dynamics of the draw. I have been very fortunate to talk bow building and build selfbows with some of the best bowyers around, you could never learn all there is to know about building bow in several lifetimes...Glenn...

[Dennis La Varenne]

Glenn,

More's the pity about the offset tiller. Here I was thinking that I had invented something new.

Most of these blokes must be keeping it to themselves because nobody has published anything on it that I have read other than Dean's today.

I just cannot find anything in print, even in Robert Elmer's books which cover the ground up until the end of WWII. I would be very surprised if it is general knowledge anywhere in wood bowmaking. None of the old reference works seem to cover it, and it deserves a chapter of its own.

Can you cite some of the users apart from Dean please? I would like to look up what they have to say if there is anything available.

I posted my effort here because I considered that I had done something important and useful which I am obliged to share around, not keep it to myself. The internet is the best way to make knowledge publicly and universally available.

I just wish some of these other people in the know had done so too. Even Dean Torges in HOB just made a rather passing explanation of his offset pulley tiller which I think was worth a whole chapter of his book, it is so important a bowyer's tool.

I will keep my adjustable version and use it for pretty much everything from now on and will adapt it to the pulley system shortly.

I will still keep my in-line tiller for my ELBs and similar no-handle designs because you find the place to put your hand by feeling for the balance point on them and the limbs bend around a central point.

That said, the offset tiller is a critical godsend to the built-in handle designs because you are stuck with a defined handle area and your limbs must accommodate to that handle.

Regards,

Dennis La Varenne

[Glenn Newell]

When I travel led to the States for the first time in 1994 and I went to some of the big Traditional shoots where 10,000 people would turn up and Traditional Craft Expos where bow building was being taught offset tiller was being used then by a lot of people. Really at the end of the day offset tiller is common sense. Why draw a bow from the centre of a bow and then hold the bow in a different place and draw a string from a different position, the first thing you will do is pull the bow out of tiller.
I have met many of the authors who have written books on Traditional Archery Crafts in the USA and I can tell you from first hand experience there are many very knowledgeable people who write books and some of them should give it away, one author I met was only interested in is own fame and buy my books. When I had a look at his bows I couldn't believe how basic they were, I had seen and shot much better bows you will never hear of. Some people are capable of the most amazing work but don't have the ability to put it down in writing.
When I went to the Pope and Young Museum and net the St.Charles family it was a major turning point for me with making selfbows and Glenn St.Charles was extremely knowledgeable and only too keen to pass his knowledge on.
Dean Torges is not the only person to use offset tiller but only one of many and he has been making selfbows since 1957. I did meet Dean in 1994 but I only spoke to him for less then a minute but it wasn't until I met him in 2000 when I spent a month with him learning the finer points of the craft. I also built a bow with Gary Davis whom you will never hear of in books but s a ledgen in the selfbow field in the USA. Mickey Lotz The Ferret is another just to name a couple.
Inline tiller is the only way to tiller a cross bow pod, whereas offset tiller is the system used to tiller a hand drawn bow...Glenn...

[Dennis La Varenne]

Glenn,

I am convinced of the value of the Offset Tiller, and I am glad I 'discovered' it from my own efforts. It has more impact that way and you are more likely to take some notice of others who also 'discovered' it. It is the most convincing argument on behalf of an idea one can have - to find it out for oneself on one's own.

It doesn't really matter that, faced with the same problems, others have come to the same idea elsewhere. That only validates one's thinking. A similar problem around the world usually ends up with the same solution.

I have just done a bit of web surfing looking for anything on tillering and not really found anything related to this topic. Lots on setting up the tiller of compounds and some very basic explanations of the principle, but nothing specific to the actual tool itself, and certainly nothing on the offset tiller, disappointingly.

As you say, a lot of people know about and have used it, but aren't going public with it even in forums like this one. Curiously, even Dean Torges doesn't seem to call his edition an Offset Tiller for some reason. I think that is a very specific and descriptive name for the thing which distinguishes is from the traditional In-line Tiller.

Anyway, Volume 4 of TBB is coming out in the near future and perhaps it will have something on 'The Offset Tiller - Its Theory and Practice', so to speak.

Regards and have a good Christmas season,

Dennis La Varenne