How do YOU find the hole?


I need to drill two armboards for arms that aren't commercially popular. What method / tools have you folks used to find the proper location to drill the hole to mount the arm in the armboard? Obviously, i'm looking for the most accurate method that is the simplest and costs the least : ) Sean
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PS... I'm only kidding. I'd rather spend the money to do it right than to hodge-podge together something that will chew up records and spit them out :(
sean
You are welcome, Sean, and good luck on the other arm. Which Pioneer 'table is it? I may have one, providing it is a PL12D, and will simply measure the tonearm-to-pivot distance from the 'table itself.
I was able to find the info that i needed on one arm, but not on the other ( so far ). Since it is an OEM Pioneer arm off of a vintage table, i don't know if i'll ever be able to find it. I do appreciate the responses and suggestions though. Sean
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Sorry I'm so late to this thread. I had to go back and look up my Graham arm instructions from 1996. I recall reading about two positions. The Seagrave/Baerwald position optimizes performance near the outer edge and inner grooves. The Loefgren position optimizes in the mid grooves. (I couldn't find these on Google. Maybe the Graham site used to post a white paper that he would be willing to email?) Most people choose the former. The actual difference in position between the two is so small (1/8"?) that I personally wouldn't attempt any of this without a template. Good luck.
If you could post the arm part number then maybe someone has the spindle to arm pillar required dimension.
Sean I'm not sure if this is what you're asking, but get an ink pad. Put the bottom of the base on the pad. Then stamp the image on the arm board, and use the image to locate the holes. I am assuming of course that you do not have the template for the arm.

If this is not what you are asking, just ignore me and chalk it up to youthful ignorance.
While i don't know if i'll be able to find the specific info that i'm looking for there, The Vinyl Engine is a GREAT resource for vinyl related subjects. GOBS of pictures of various tables, arms, etc... Thank YOU John.... Sean
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Sean...I know that I have seen writeups on all the angles and forces involved with a pivoting arm. In fact a lecture I went to about how to set up a pivoting arm is what convinced me to go to linear tracking. It is impossible to get everything right across the recorded range of the LP.

If I had to do it....I would set the tracking angle so that it is correct at the midpoint of the LP recorded range. To accomplish this:

1. Make a template of the plan view (looking down) of the arm. The pickup is mounted at an angle on the arm, or the arm has a bend in it.

2. Put the template on the armboard with the stylus point at the radial distance from the turntable spindle that corresponds to the midpoint of the recorded area.

3. Draw a line tangent to the groove at the point where you located the stylus. This is orthogonal to the radius out to that point.

4. Pivot the template around the stylus point until the arm pivot point lies on the line which you drew.

5. Drill away.

You might want to compare an existing deck (that you know is right) to what my method would yield.

It might theoretically be slightly better to set things up for a point nearer the end of the recorded area, on the basis that things get tough for the pickup towards the inner grooves, and it might help to have tracking angle more optimum at that point. However, I don't think that there would be any significant improvement by doing this.
You need the template for the arm. Otherwise try the Vinyl Engine library and find the tonearm-pillar-to-spindle distance, and then simply measure it out to the best place on your tonearm board. The library always tells you the item is not available after you sign in, so you return to the library, and click on the tonearm again. It'll be there. At least, that's how it works for me. Good Luck.
I've got Forstner bits and a drill press, but i need to know how to locate the correct location for the hole. Sean
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Sean,

You need access to a drill press. As mentioned above Forstner bits are preferred. It's been my experience that these bits bore perfectly from the top BUT clamp the piece securely to another piece of sacrificial wood on the bottom for the bit as it exits the armboard. This will eliminate any chance of splintering. A single Chinese bit will cost about $10 but an entire set can be had for around $25. They are available in English and metric sizes. Buy the right one and you will save yourself the trouble of having to sand the hole by hand for final fit. Oh yeah, drill a small pilot hole first.
I like to let the hole just find me.

Aw, c'mon Sean, that one was just too easy the way you asked!! Whady'a expect man?

Marco
C'mon guys, how can you do this to me? I ask an "honest" question and these are the responses i get??? : )

Honestly though, i've got a couple tables here that i need to get set-up. With 6 different linear tracker's, i've not lost the faith. These tables aren't for me hence the "back-sliding" into pivoted arms. As such, i need to know what type of "universal" tools work most effectively at finding the right spots to drill various arm / table combo's. I'd like to keep something on hand just in case something like this comes up again. At the same time, i don't want to spend more than i have to as i don't intend on doing this on a regular basis. Know what i mean ??? Sean
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A drill press would help. Forstner bits make the cleanest straightest holes.If you have trouple , mark up the boards and I will drill them for you.