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Being a novice at this craft, I have a few questions regarding tuning forms. I purchased a set of forms from a maker in Nevada. I have had a problem with consistency in my strips, as a rusult, I took machinist dye, coated the forms and ran a flat file on them. The steel was fairly uneven, so I flat filed the forms, then polished with a series of diamond stones, much like tuning the soles of my planes. Could this have altered the 60 degree bevel enough to render the forms less than adequate? If so, what would be the best way to tune the groove? Any tips would be greatly appreciated. (Jon Holland)

    No, you have likely not changed the angle in the groove at all.  Certainly not enough to notice.  I suggest never messing with the groove.  Just leave it alone.

    Now as for the inconsistent angles, here are a few tips to help keep things congruent.

    First, keep your blades extremely sharp.  I won't repeat this endlessly, but it is THE #1 cause of bad angles.

    Second, check the enamel sides of your strips closely.  Are there dips or bumps around the nodes.  When the strip is in the form, but with plenty yet to plane away, can you see a gap near a node?  If so, you need to work those nodes over again.  Does the small end of the strip lift out of the planing form groove when you start planing?  If so, that strip is crooked.  When you're just starting out, working with perfectly prepared strips makes things much simpler.  A more experienced maker can work around some less than perfectly prepared strips.  But now isn't the time for cutting corners.  Remember, we're trying to isolate a problem here.

    Third,  is the plane iron level with the forms when you are planing?  I'm not asking are you holding the body of the plane level, but is the iron level?  To check, place your plane on your forms.  Back the blade in till it won't catch on the form when you slide the plane forward.  Now slowly move the blade out (deeper cut) until it just begins to catch on your forms.  Notice where it cuts into the forms.  Does it cut right in the center and all the way across?  I'll bet it doesn't.  I suspect it will cut on one side or the other.  Adjust accordingly.  It doesn't matter how skewed the blade looks compared to the opening in the sole.  It MUST cut squarely on both sides of the forms.  (thanks J Channer for this tip, years ago)  You think you'll ruin your blades by doing this, but you won't.  The forms are made of mild steel.  The blade is hardened steel.

    Finally for now, how are you proceeding with planing the strips?  Start with a .004" or so cut (test on scrap bamboo and measure the shavings).  How you place your strips in the form is important to keeping angles correct.  Don't just place the strip in the forms in the place where, if you are down to metal the strips are at their final dimensions.  Instead, draw the strip backwards, towards the deeper end of the forms, until you are only taking a cut on the tipmost 10-15 inches.  Make three passes on one side, then flip.  Three passes on the second side, then flip.  Now advance the strip in the forms a few inches.  Two passes, flip, two passes, flip -- then move the strip forward again.

    By leaving only a sliver of the bamboo strip above the surface of the forms, you can't mess up the angles quite as easily.  Working with only a little exposed bamboo also trains you to hold your plane level to the surface of the forms pretty quickly.

    One more thing... correcting angles is fairly simple if you still have plenty of bamboo left to remove.  I have a treatise about that somewhere in the Tips page.  (Harry Boyd)

      One more point I think Harry missed:  you need the enamel side flat, or at least a good wide flat area.  It has to be done eventually and it's many, many times easier to keep the angles at 60 degrees.  Don't ask how I know this.  (Neil Savage)

        Good point, and one I wasn't going to talk about.  The enamel side needs to be quite consistent.  For years I flattened it out before beginning the final planing, but no more.  Doing so removes quite a swath of important power fibers.  My methods always involved 2-3 passes with a L/N scraper, followed by sanding with the fine pad of a "Supr-Sandr," and following that up with 400 grit sandpaper.  Of course, one could always do like Golden Witch suggested and just flatten things out with a big belt sander.

        I don't do any of that today.  Instead I pay close attention to the other details of strip preparation as described before.  When I'm about .040" oversize, I turn the enamel side up in the planing forms and use a custom made sanding block to remove the enamel.

        To make the sanding block, I attached coarse self-adhesive sandpaper to a scrap piece of a whole culm of bamboo, and used it to make a concave radius in a 1" x 1" x 4" piece of hardwood.  To the concave surface of the hardwood sanding block I attach 220 grit self-adhesive sandpaper.  The concave sanding block allows me, in theory, to follow the radius of the culm while removing the enamel.

        You have to be more careful, and perhaps more experienced, when working with a radiused enamel side.  Again, sharp blades make all the difference in the world.

        Does it make a huge difference?  Probably not.  But might it make a small difference?  Possibly.  And the differences between rods are a thousand different small things.

        This is one of the very few things I do differently than I teach.  Flattening the enamel side certainly makes it easier to keep strips oriented correctly in the forms, and we ought to take every precaution possible when learning this stuff.  I'm trying hard not to say that flat enamel is for newbies.  That is NOT what I mean.  I think it's a great way to make rods.  It's just that removing power fibers is never good, and 3-15 thousandths (depending on timing, and methodology) -- maybe more on quads -- of power fibers have to be removed from the center of the strip to get things flat all the way across.  (Harry Boyd)

          I guess we are all aware of the need to preserve power fibers, but the concomitant need to present flat sides to the forms is, in my opinion, more important still.

          To that end, I am quite happy to take a very, very fine series of passes with a sharp block plane to achieve this.

          I have some caveats, though, chief among which is the need to avoid having to remove any more cane than necessary; which means doing the flattening as late as possible in the process so as to minimize the dimension of the chord removed.

          I believe, also, that there is a lot more need for caution in the butt section than in the tips.  My experience with most tips, if using good  bamboo, is that the finished section consists entirely of "power fibers" anyway , so removing a few from one side really doesn't do any significant damage.

          It's a bit more critical when planing the larger butt strips, though, and once again, the answer seems to be to perform the operation as late as feasible, on strips that are as small as possible.

          Just a couple of points further to the discussion - I flame my rods, so we ought to remember that flattening the enamel surface, once the nodes have been dealt with, amounts to little more than removing the charred material in any case.  And I choose to do the removal/flattening  with a sharp L-N block plane, because I feel that there is a tendency inherent in scrapers to follow the existing contours, and that is not what I want, obviously, whereas a plane  does get it all level and integrated. I believe, almost as an article of faith, that there is nothing you can do with a scraper that cannot be done at least as well with a good plane.

          Here endeth the heresy session!  (Peter McKean)

          That's why I said "at least a good wide flat area".  I usually try to get the center flat and nearly as wide as the finished strip will be, and I still have trouble with my angles.  That part is going to have to come off sometime, unless you are making the "flats" curved and it sure makes life easier, especially for a beginner (like me.)  (Neil Savage)

            Hmmm, I'll have to disagree just a bit here.  Not with the enamel thing, the form... groove...thing.

            I have seen way too many brand new forms (both pricey and inexpensive, no names mentioned of course) where the groove was not cut all the way through the form leaving a "shelf" if you will, at the bottom of the groove. No strip is going to sit properly in that situation.

            DO make sure that the slope of the groove makes it all the way out the bottom and doesn't abruptly end leaving something like this \_ _/, instead of something  like  this, \ /.  If there is a flat spot in there, you'll need to deal with it. You'll never get a proper angle if it's there. A triangle file thingy will solve the problem. It's likely to only be a here and there thing. Check BOTH sides tip and butt!  (Mike Shay)

              Here’s a question.

              If you adjust the forms totally closed, place your depth gauge on one end and slide the depth gauge to the other end without taking it off the form, what should be the decrease in depth per inch and what does it mean if this decrease is not consistent?  (Frank Drummond)

                To me it would have to depend on how much fluctuation there really is? I think the general consensus is .001" of depth per one inch of length.  It ain't much but it's there! Keep in mind, sliding your indicator across your forms isn't necessarily a good thing.  (Mike Shay)

                  Years ago I purchased a new set of forms and built a number of rods using them.  However when I decided to build a finer tip rod I couldn't close the forms enough to get the depth for the 2nd and 3rd station.  As a result I took the time to close all the stations and measure the minimum depth of every station to see how close them came to the .001" slope per inch and they were extremely inconsistent (the slope between the 5" stations ranged from a low of .002" to a high of .012" and there were no adjacent stations that measured a .005" slope).   The maker did agree to replace the forms but better yet, thanks to UPS losing the forms, I was able to get my money back from UPS and decided to buy a set of Bellinger forms.  However, before I bought my Bellinger forms I got them to give me all the stations depths with the forms fully closed before I purchased the forms so I could see how close they were to the .001" slope/in ch and they were extremely accurate.  (Bob Williams)

                You don't want to slide your depth indicator on your form.  That's the easiest way to get your 60 degree tip all out of whack.  If you really want to check this (in my opinion), you'd want to mark the form off at 1" increments and then measure those.  Ideally, you'd have .001" increases from tip to butt at each successive measuring point.  (Todd Talsma)

                Or maybe this: What is the best way to check a set of forms for properly machining and accuracy?  (Frank Drummond)

                  If it were me, I'd take the forms apart and carefully measure the angle of the intersection of groove & top surface of the form on each rail. It should be 60°. Another check would be to insert a 60° threading tool in the groove of the closed form and see if the sides of the tool not only makes complete contact with the groove surfaces at all locations along the form's length, the sides of the tool must also be perpendicular to the form's top surface. If any of the above is not true, the form was not machined correctly, period!

                  Measuring the slope of the groove is entirely another matter. What ever the slope of the groove it should be consistent. Usually .001"/inch of length. To me, the most accurate measurement of the groove depth at any one point can only be done with a properly calibrated dial  Indicator and a 60° point. Reason being; the depth at any point is only measured at the tangent, or the contact, to the side of the 60° point. This is a very precise point along the length of the groove and the side of the point. Do not slide the 60° point along the groove. This could put a flat spot on the side of the point causing erroneous depth reading.

                  If the forms are not accurate and the maker of the forms won't correct or help, let me know. I have some Excel worksheets to help you fix them. (Don Schneider)

                    I’m not having problems with my forms. Strips are accurate and blanks are coming out of the string with no glue lines. It’s just something I think about while planing and I just wanted to ask the question. Because I wanted to eliminate FUD (fear, uncertainty and doubt) as best as possible when I got into rod building I purchased my forms from Jeff Wagner. They were dead on right from the start and I knew if I did have a problem Jeff would handle it.  (Frank Drummond)


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