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Rule

I've come to realize that my planing form is skewed. I have planed out 5 rods now, the last is still unglued, the first 4 have all been nice rods that I had a lot of trouble with. First I thought I'm just learning.  Then I thought that the clamp I used on the butt of a strip to hold it down while I planed was forcing the strip too deep into the groove. I made the mistake of using a V-block on my calipers which was giving me great numbers, within .001" on all three sides. This last rod I've taken more care with and started comparing the corner to corner distance and there there was a much greater discrepancy than the corner-to-flat measurements from the V-block calipers. These are strips that were pretty damn equi-triangular coming out of the beveler.  (Henry Mitchell)

    Measure the depth of the groove at some point along the forms with the drill rod method. Use two rods, one small diameter that just clears the top of the forms, and a larger rod that just touches the sides of the groove. If you get different depth results with the two rods, it proves the angle is incorrect.  (Tom Smithwick)

    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. 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.

    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)

    Like the purchaser of the expensive planing form, my bars were not within acceptable tolerances when they arrived.  The difference was I purchased the  cheapest bars available.  However, being on a budget that was OK.  At the direction of my mentor, I took a Nicholson mill file and after about 12 hour of milling, the tops of the bars were just about .001 or with in acceptable tolerance.  We met yesterday to plane the final numbers on my taper before gluing the strips up.  After readjusting the bars about three times and still not coming up with the correct dimensions, my friend got to looking at the angles of the forms.  They to were wider at the top than 60 degrees and flared out.  Remedy, according to my mentor is to purchase a triangular file making sure it is cut at a true 60 degrees.  Then, take and cut the center of the file out making it a few inches long. The cut section of file is then mounted to a block of wood making sure it remains square.  All that is left then is to mill the grove within acceptable tolerances.  I have not yet done any of the later  and have possibly left something out.  But I know that I have several hours left of milling.  When I purchased the bars, I was advised that they would need to be "cleaned up"  and then occasionally "touched up" to make sure they remain true.  I now see that I got some pretty good advice.  By not being very experienced,  I will leave it to the rest of the builders on the list to correct any bad information I may have  put out here.  (Steve Tucker)

      The block with a file glued to it will work but there are some pit falls. The bottom of the block must be held parallel to the top surface of the forms at all times or you may end up where you are now, wider at the top on one edge or both. Also, setting up the forms for this tool is critical and time consuming or the slope of the groove may end up being something you don't want.

      Go here to read my article.  Don't worry about the name, the setup and procedures work and are the same for metal forms. Look at the part about cutting the groove. There also is a part in there that tells how to make a File Plane.

      Don't know what length your forms are but I have spreadsheets for "forms setup" to cut the groove or "forms tune-up" for 4', 5' & 6' forms. If you are interested, I can download them to you. The spreadsheet and the File Plane make it very easy to tune your forms.

      Todd had a list of who had the loaner File Planes at one time. Maybe you could get one of them, although they are not hard to make. The best file to use is one that is not tapered and about 1/2" on a flat. Mark Babiy found some in Canada but don't know if they are still available. Mark?  (Don Schneider)

        Well, I am not Mark, but I found a couple triangular files in Calgary.  I bought one from House of Tools - I think a Nicholson brand and I think 6".  I used a hacksaw to trim off both ends (the tang and also the thinner end).  That file seemed to have a consistent width for about 2.5" and then thinned down.  Cutting off the ends took a while  :)   I got the second one from Lee Valley.  It had finer teeth and I think it was a consistent width.  I read that a "Vixen" was ideal, but I could not find one.  I was told that Snap On Tools carried them, but I could not find them.

        I made a holding block from a piece of 2x4 shaped to my hand with a piece of phenolic plastic glued to it and then the file glued to the plastic.  I figured that the plastic would slide nice on the form.  It did, but it also picked up shavings like crazy and the epoxy gave up frequently - causing a delay while I reglued it.  I reglued about 5 or 6 times.  I followed the process on the sites mentioned earlier in this thread.  I had never worked metal when I made my forms from scratch - it is straightforward - just needs some sweat equity.  You could possibly true up your forms in an evening.

        I would open the forms a few thousandths at a time so that I could not "wobble" too much and keep the file at the right angle.

        You probably only want to take off a few thousandths to true up your forms, so it should be quick.  Take it slow, take off a couple of thousandths, clean up the filings, close up the forms and check/measure your gap and angle.  I used a Starrett thread gauge and a Golden Witch large 60 degree point to check my groove.  (Greg Dawson)

        What I do is open the forms till the file board is flush with the top of the forms and the file is just touching the metal at the big end of the groove. Then open the forms .005 at each station towards the small end of the groove. This will keep the board flush on top of the forms the full length of the forms. The file I use is recessed full length in the board. When taking depth measurements, they should read the same the full length of the forms at each station. Being able to keep the board flush on top of the form will keep it from making the groove wider than 60 degrees.

        I have found this worked well on the four sets I made. Hope it is clear in what I am doing.  The article in Power Fibers explains it in more detail.  (Tony Spezio)

          I know the procedure well. Tried to use it for the first set of forms I built. I quickly found the file board had to be  nearly flush with the top surface of the forms for each pass. This required numerous adjustments of the forms just to get to the point of the file making contact the full length of the groove. I remember thinking: "Gee, I only have .060" to go and I'm only on the butt side."

          There had to be a better way. I either had to find a way to move the file up/down or continue to adjust the forms. The end result was the File Plane. The Bit Plane removes metal faster but is not as well suited for the final few thousands. Use of either of these tools only requires one setup of the forms and saves a tremendous amount of time. I later developed the spreadsheets which even saves more time, especially for tuning forms or checking your progress when making new forms. Using these tools, accuracy of ± .0005" on 5" centers is not difficult to achieve and the cross section of the groove is an equilateral triangle end to end.

          Using these tools anyone can make forms, even Todd did it....:>)  (Don Schneider)

            I did not mention that I remove most of the unwanted metal any way I can including using a 4" grinder before using the file board. I just use the file board for finishing up, not to remove the bulk of the metal. I guess I left the impression that I remove all the metal with the file board. Yes, that would be a lot of work and a lot of resetting forms.

            I agree with your message below, if I had the file planes at the time it would of been a lot easier. I have built my last set of metal forms but if I decide to make another set, I would build a file plane first. I have a set of forms that I acquired, they need to be almost totally redone as far as the groove goes. Am trying to recover a set of your file planes before I even think about starting on it. No luck yet on getting them.

            I thought it might help S Tucker get his forms squared away being that he already had the groove in the forms.  (Tony Spezio)

            Oh, thanks!  That gives me a big vote of confidence!

            I found that I could make a set of forms, even using Don's instructions! ;^)

            The instructions are indeed very detailed and easy to understand.  I'd highly recommend them.  As Don said, I do have a set of his tools floating around.  If you need them, I can contact who has them and get them mailed to you. (Todd Talsma)

Rule

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