Why are lead acid battery terminal posts

[billskip]

So why are so many propellers on shafts on a taper?

You dont need a back stop to prevent the prop riding along the shaft...

 

[Rappey]

Another advantage of taper is only needing a minimum turn of the clamping nut, especially when connecting in some hard to get to position.

 

[BabaYaga]

I can't agree at all with the idea that a taper is not a sound connection. For a cylindrical socket to pass over a cylindrical post it must have clearance, then if it gets pinched down to fit by a bolt then it is warped off-cylindrical so it can only contact the cylindrical post along a few lines, not a large surface. THAT would not be a sound connection. A conical socket can fit onto a cylindrical post exactly (as long as the cone angles are the same) and should not even really need the bolt. In machine tools it is really common for a hard steel cone and a hard steel conical socket to be all you need to hold a tool in place, even a drill bit, with only a fairly light pressure to get the connection firm. The friction between two conical surfaces that are really in contact all over is enormous. Probably more so with soft lead ones that can deform to an exact fit and be thumped on with a hammer.

Pinching down a cone with a bolt, like battery terminals do, also deforms the cone and would make it a worse fit if you started tightening up the bolt before the cones were well in contact. In practice you don't do this so it probably doesn't. Yes in theory the cone converts a small % of the force to an outward thrust but the taper angle is so small that that force is sine of a small number and is really really small. If it doesn't grip, probably you have a part with a wrong or damaged taper angle

Has anyone really run into a problem of these things popping off the lead cones? I had the opposite problem - took some sweat and swearing to get them to move! Someone must have followed the hammer theory a bit too vigorously. It just takes a tap...

Some good points here on the potential drawbacks of a hypothetical cylindrical battery post and clamp. Really nothing that I would advocate.
Not sure that the comparison to conical connections in machining tools is valid, as I believe these are manufactured to very fine tolerances (and are all about transmitting torque, unlike battery posts).
As already mentioned, my view is that the traditional tapered post/clamp kind of works only because of the nature of the materials involved, creating sufficient friction. Some googling suggest that the taper is 1:9, I think you may underestimate the angle and the outward thrust that can be created when the clamp bolt is tightened.
My experience comes from using the type of brass SAE post adapters (linked earlier) with the battery clamps as seen in the photo below, which created an unreliable connection. The fact that this type of brass adapters are often knurled (mine were not) indicates to me that potential lack of friction is a known issue with tapered compression fittings (or should be).

 

[Stemar]

Tapered posts have often caused me problems.

Very true. Far too many posts taper off into squabbling irrelevance

 

[Graham_Wright]

The No 2 morse taper in the tailstock of my lathe holds a Jacobs chuck. It is held by friction alone. No draw bar to tighten it. I just push it in & it grips. I can put a 15mm drill in it & it will drill into steel without slipping. The morse taper does not rotate The steel it is drilling does.
There is no woodruff key either
The same for my pillar drill, except in that case the quill rotates & the steel is clamped. But there is no nut to hold the taper. It is held purely by friction between the male & female parts

However, there is a danger.
Most of my machines are CNC. It is not advised to use a tapered drill in a tool turret. If, for some reason, the drill snatches or seizes in the hole it is drilling, it can be pulled out of the tool holder. If it remains in the job, the chances are that there will be a collision with following tools. If it only pulls out partway, it can damage the turret. Recovery can be very expensive (I speak from experience!).
It is advised to avoid taper shank drills in this application or to lock them in the tool holder.

 

[ean_p]

Some good points here on the potential drawbacks of a hypothetical cylindrical battery post and clamp. Really nothing that I would advocate.
Not sure that the comparison to conical connections in machining tools is valid, as I believe these are manufactured to very fine tolerances (and are all about transmitting torque, unlike battery posts).
As already mentioned, my view is that the traditional tapered post/clamp kind of works only because of the nature of the materials involved, creating sufficient friction. Some googling suggest that the taper is 1:9, I think you may underestimate the angle and the outward thrust that can be created when the clamp bolt is tightened.
My experience comes from using the type of brass SAE post adapters (linked earlier) with the battery clamps as seen in the photo below, which created an unreliable connection. The fact that this type of brass adapters are often knurled (mine were not) indicates to me that potential lack of friction is a known issue with tapered compression fittings (or should be).

I'm not too sure that that is the right clamp for the post there BY, or your trying to hard to make it work......!

 

[Graham_Wright]

View attachment 150136

I'm not too sure that that is the right clamp for the post there BY, or your trying to hard to make it work......!

Yes - there is something wrong there. The distortion could be due to the wrong terminal on the wrong except they are both labelled +!

 

[ean_p]

However, there is a danger.
Most of my machines are CNC. It is not advised to use a tapered drill in a tool turret. If, for some reason, the drill snatches or seizes in the hole it is drilling, it can be pulled out of the tool holder. If it remains in the job, the chances are that there will be a collision with following tools. If it only pulls out partway, it can damage the turret. Recovery can be very expensive (I speak from experience!).
It is advised to avoid taper shank drills in this application or to lock them in the tool holder.

So how is your tooling held and positioned? Are they static tools or rotating?

 

[Graham_Wright]

So how is your tooling held and positioned? Are they static tools or rotating?

I don't use taper tools, they are all plain shank. No live tooling.

 

[Capt Popeye]

View attachment 150136

I'm not too sure that that is the right clamp for the post there BY, or your trying to hard to make it work......!

Yes beat me to it , looks like the clamp is distorted by over tightening it ; often happens with incompatable size items /clamps ; my understanding is that the clamps should be a light push fit onto the posts , tightening them should only require 'nipping them up with a spanner'

 

[Daydream believer]

However, there is a danger.
Most of my machines are CNC. It is not advised to use a tapered drill in a tool turret. If, for some reason, the drill snatches or seizes in the hole it is drilling, it can be pulled out of the tool holder. If it remains in the job, the chances are that there will be a collision with following tools. If it only pulls out partway, it can damage the turret. Recovery can be very expensive (I speak from experience!).
It is advised to avoid taper shank drills in this application or to lock them in the tool holder.

In which case one uses a draw bar, as I do on my mill with a single tool. With a multi tool turret there are bespoke holding systems. But one would not find these on battery terminals- Screw in the top of the cup - Yes perhaps.

 

[Graham_Wright]

In which case one uses a draw bar, as I do on my mill with a single tool. With a multi tool turret there are bespoke holding systems. But one would not find these on battery terminals- Screw in the top of the cup - Yes perhaps.

On the machining centres, there are indeed drawbars but they draw in a socket which takes the taper shank drill. Bangs are not so serious as generally the machines are attended and if the tool drops it drops vertically. On the lathes, tools are held in toolholder with side screw attachment.
Bit of a Fred Drift this!

 

[billskip]

Bit of a Fred Drift this!

You think its tapering off.....

 

[BabaYaga]

View attachment 150136

I'm not too sure that that is the right clamp for the post there BY, or your trying to hard to make it work......!

Yes - there is something wrong there. The distortion could be due to the wrong terminal on the wrong except they are both labelled +!

The clamp and the adapter are both the correct ones. The reason that the clamp bolt seems over tightened is that the compression forces the clamps to rise on the post, all because of the tapered shape of the post combined with insufficient friction. Which kind of proves the point I'm trying to make.
So surely something was wrong here. That is why I quickly altered the connections to what is illustrated in post #19.