Double Bass Yet another end pin question

[Andy Mopley]

Left Shoe Bass Studio: Making a bent endpin

I am thinking of making one of these, to try, but are they the poor man version of an end pin, a sort of entry level attempt? Are there any real disadvantages?

Regards to all

 

[turf3]

Can't be any harm in trying. Don't modify your existing one, buy a length of bar stock the right diameter and experiment with that. I just scanned the article quickly but it doesn't appear to mention that you'll need to file some notches.

Personally I think the end cap should be in line with the main axis of the pin to help in balancing the bass, though I have never seen one made that way. That would require two bends in opposite directions, of course. One of these days I'll try it out with the remaining 10 mm stock I have in the garage.

One note is that it is basically impossible to find metric size stock in any general hardware store in the US. You will need to order it from someone like McMaster-Carr. Or you could contact your local metal supplier, but they probably sell in minimum 10 foot or 20 foot lengths. 3/8 will not be a good substitute for 10 mm.

 

[robobass]

I must object. Admittedly I have a stake in this, as I offer a competing solution. One must distinguish between "angled" endpins, i.e. Laborie, Lammax, Robpin, and "bent" endpins as are described here. I don't like bent endpins. They put a lot of sideways force on the socket, which translates into the bottom block. They tend to bounce, and also put a lot of force on the set screw, which is already a weak point. It is much better mechanically to have the endpin extend in a straight line from the bottom of the bass to the floor at the desired angle, rather than have it bend somewhere in the middle.

 

[turf3]

I must object. Admittedly I have a stake in this, as I offer a competing solution. One must distinguish between "angled" endpins, i.e. Laborie, Lammax, Robpin, and "bent" endpins as are described here. I don't like bent endpins. They put a lot of sideways force on the socket, which translates into the bottom block. They tend to bounce, and also put a lot of force on the set screw, which is already a weak point. It is much better mechanically to have the endpin extend in a straight line from the bottom of the bass to the floor at the desired angle, rather than have it bend somewhere in the middle.

All good points, also a twisting moment is applied which at least theoretically could twist the endpin mount in the bottom block.

For myself I am contemplating a double-bent pin which would leave the contact point with the floor basically in line with the axis of the hole in the end pin mount, but would have the rubber tip contacting the floor more flatly.

 

[robobass]

All good points, also a twisting moment is applied which at least theoretically could twist the endpin mount in the bottom block.

For myself I am contemplating a double-bent pin which would leave the contact point with the floor basically in line with the axis of the hole in the end pin mount, but would have the rubber tip contacting the floor more flatly.

The twisting moment probably won't turn the socket. There is pretty good holding force there from the tailpiece wire. But, that twist will gradually damage your thumb screw and collar threads.

I can't quite parse your second point. If you only want the rubber to meet the floor at 90°, then why not simply get a ball type rubber? It would be way simpler, and reported success rates are high (I still don't like it). If slippage is the problem, I think your idea wouldn't help much.

Most people do a bent or angled endpin to change the balance / center of gravity. It also definitely reduces the forward walking tendancy of your tip to have it set more under your bass than out in front.

Hope this helps.

 

[turf3]

Here's how I've been thinking about it.

If you take an ordinary double bass, there's a rotational axis from the point of contact of the end pin and the floor, to some point up top that's a combination of your left hand on the neck and the place where the edge touches your belly. With the ordinary end pin, the center of mass of the bass is pretty close to that axis, although I expect the mass of the ebony fingerboard and the neck actually mean the CM is "above" that rotational axis, in other words displaced from the axis toward the bridge/fingerboard/top plate side of the bass.

Now if you make the contact point of the end pin to the floor offset from the original axis of the end pin in the way most bent or angled end pins do, you are creating a new pivot axis from somewhere up top (a combination of the left hand on the neck and the place where the edge touches your belly), to the contact point of the end pin and the floor. The center of mass of the bass is about where it was, but the rotational axis is now below it by a considerable amount (in other words, closer to the floor). This would seem to be the opposite of increasing stability.

What I was thinking was, why not have the end pin bent (or otherwise modified) so the modified axis of rotation actually passes above the center of mass (i.e., the center of mass is closer to the floor than the rotational axis)? It seems like this would enhance the stability of the bass.

I may try to modify the pix of the Rob Pin to show better what I mean.

 

[turf3]

Something like this:

 

[turf3]

Imagine, however, that the end pin part is quite a bit further to the northeast than how it came out in my patch-up, and you will see what I mean.

OK< more like this: