Shopsmith Forums

On my recently acquired 520, when I tighten the headstock lock, the wings of the lock are at the 10:00 / 4:00 position. This is the most inopportune position as it becomes a knuckle scraper when changing the speed. So, I was wondering if there is an adjustment that can be made (short of re-drilling the hole in the shaft that holds the wing nut) so that the "tight" position becomes something closer to the 2:00 / 8:00 position.

mountainbreeze wrote:On my recently acquired 520, when I tighten the headstock lock, the wings of the lock are at the 10:00 / 4:00 position. This is the most inopportune position as it becomes a knuckle scraper when changing the speed. So, I was wondering if there is an adjustment that can be made (short of re-drilling the hole in the shaft that holds the wing nut) so that the "tight" position becomes something closer to the 2:00 / 8:00 position.

I have two machines that both lock differently than yours. One of mine is about 2:00/8:00 and the other is 1:00/7:00. Unfortunately, I don't know how to make a deliberate change to the locking point.

I am almost certain, however, that if you would pull the wedges out and then reinstall them that yours would lock at a different location.

Hmmm, I gotta think on this.

I am curious though. Why do you find the locking points to be an issue? Until you asked, I had never given this any thought. What am I missing.

It is the quill handle that always seems to be where I don't want it. Fortunately, it can be relocated.

mountainbreeze wrote:On my recently acquired 520, when I tighten the headstock lock, the wings of the lock are at the 10:00 / 4:00 position. This is the most inopportune position as it becomes a knuckle scraper when changing the speed. So, I was wondering if there is an adjustment that can be made (short of re-drilling the hole in the shaft that holds the wing nut) so that the "tight" position becomes something closer to the 2:00 / 8:00 position.

How about just pulling it off and slipping a thin shim washer behind it? Its been a while since I had one off and I don't remember what I had for breakfast. That would be where I would at least start looking at possibilities.


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mountainbreeze wrote:On my recently acquired 520, when I tighten the headstock lock, the wings of the lock are at the 10:00 / 4:00 position. This is the most inopportune position as it becomes a knuckle scraper when changing the speed. So, I was wondering if there is an adjustment that can be made (short of re-drilling the hole in the shaft that holds the wing nut) so that the "tight" position becomes something closer to the 2:00 / 8:00 position.

Tight happens when the two opposing wedges press against the outer sides of the way tubes. Since the pitch is the same on both wedges, repositioning them on the threaded shaft accomplishes nothing since each must be rotated a full turn. That can only change the number of full turns required or the position of both wedges on the shaft when tight(they affect each other and the critical thing is that both have available overtravel capability - no bottoming out).

However since it is the separation of the wedging surfaces that determines the clamping action, filing one or both of the wedging surfaces will require the shaft to be rotated further to 'clamp'.

The filing needs to remove the wedge dimensions a 1/3 of the thread pitch total - 4 hour change). Gluing shims to the wedges would also work(until they fall off!;)).

Since the thread pitch is 16, the difference in wedge separation is about 0.02"

There is nothing to shim. Remember that the locking wedges travel on a threaded rod and when locked they put pressure on the tubes.

However, I just changed the position at which mine lock. I did this by unlockimg the wedges completely. I then grasp the locking handle and pulled it toward me and then pushed it away (three or four times). This alternately engages and releases the wedges from contact with the tubes.

When I locked the headstock, it now becomes secure at 3:00/9:00. I have no explanation - just observation.

dusty wrote:There is nothing to shim. Remember that the locking wedges travel on a threaded rod and when locked they put pressure on the tubes.

However, I just changed the position at which mine lock. I did this by unlockimg the wedges completely. I then grasp the locking handle and pulled it toward me and then pushed it away (three or four times). This alternately engages and releases the wedges from contact with the tubes.

When I locked the headstock, it now becomes secure at 3:00/9:00. I have no explanation - just observation.

Shimming the wedge surface(the inverse of filing it).

I assume one or both of the wedges were slightly rotated. By loosening them in the bore, they are probably now aligned with the horizontal part parallel to the way tubes and squeezed closer together.

It is my bet the headstock lock is being overtightened just a little bit. Try to loosen the wings so they are at 9:00 and 3:00 and I'll bet the headstock is still fixed in position.

I had this same conversation on this forum several years ago and this was Nick's suggestion. Watta ya know - it worked. Speaking of horizontal use only - not vertical.

dusty wrote:I am curious though. Why do you find the locking points to be an issue? Until you asked, I had never given this any thought. What am I missing.

I find myself scraping my knuckles on the 10:00 wing of the wing nut when changing the speed.

charlese wrote:It is my bet the headstock lock is being overtightened just a little bit. Try to loosen the wings so they are at 9:00 and 3:00 and I'll bet the headstock is still fixed in position.

I had this same conversation on this forum several years ago and this was Nick's suggestion. Watta ya know - it worked. Speaking of horizontal use only - not vertical.

I long ago acquired the habit of not overtightening any of the locks. If I were to back off the lock to a slightly more favorable position (say 9:00 / 3:00) the headstock would probably not move but I would not want to raise it to the vertical position unless it were a little tighter (i.e., back to the 10:00 / 4:00 position).

A while back, I got tired of those tips being in the way and decided to trim them down.

I found that cutting off as little as 3/8" from the tips of the wings makes a great difference and there's still plenty of stock left to get a good grip.
In fact, I think it's easier to manipulate the handles when they're smaller.
Maybe my hands are just small or something, but it feels better to me.

I have now trimmed down all the wing nuts on my machine. I just used a very fine(32TPI) hacksaw. For the easily removable wing nuts, I took them off and put them in a vise. For the carriage wing nut, I left it in place and then held each tip with a pair of vise-grips and cut it off after taping a small piece of plywood on the motor pan to protect the housing. I then took a file and rounded-off the edges and then used some fine steel wool to polish them. They feel great to me and fit my hands a lot better.

I will try to attach some pictures. I took pictures with a spare, original-size handle to get a side-by-side comparison.

dusty wrote: I did this by unlockimg the wedges completely. I then grasp the locking handle and pulled it toward me and then pushed it away (three or four times). This alternately engages and releases the wedges from contact with the tubes.

When I locked the headstock, it now becomes secure at 3:00/9:00. I have no explanation - just observation.

Thank You Dusty I have big hands and this has been a nagging problem for me since I first got my 510. Not so much that I would interrupt what I was building to try to fix it, but nagging none the less.
Today after reading this thread I was in the shop using the SS and remembered your advice........................ 10 seconds! Literally! I loosened the wing nut completely and rattled it back and forth a couple of times and tightened it. Problem gone for ever!!!!!!!!!!!!!!
Did I mention Thank You Dusty!

Paul M