Pole Lathe

VO5 said:
Does this explain what you wanted to know ?
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Um, not entirely :-)

I know what a pole lathe looks like, I've seen them on telly. I understood that the work is suspended between two centres, such that it can rotate, but I was asking what, in a home-made lathe, you used for those centres, or how you made them.

The point about the coins answers it halfway, in that it seems you are using a stationary metal (steel?) cone and let the rotation happen between the cone and the coin drilled as a kind of washer. So I understand in the abstract what the centres are like, but I don't know how you made them, or what you improvised them from. Or are they simply a bought item?

Pete
 
prv said:
Um, not entirely :-)

I know what a pole lathe looks like, I've seen them on telly. I understood that the work is suspended between two centres, such that it can rotate, but I was asking what, in a home-made lathe, you used for those centres, or how you made them.

The point about the coins answers it halfway, in that it seems you are using a stationary metal (steel?) cone and let the rotation happen between the cone and the coin drilled as a kind of washer. So I understand in the abstract what the centres are like, but I don't know how you made them, or what you improvised them from. Or are they simply a bought item?

Pete
Click to expand...

The key to understanding this is that the screws are wood screws that have very sharp points because they are the type which you can drive in with an electric drill (Phillips heads).

The coins, which are pennies, have 2 millimetre holes drilled straight through and then cambered by just lightly drilling the entry hole with a larger diameter drill.

When the wood screws are driven in, they seat perfectly in the recesses, therefore eliminating sideshake and endshake.

The drilled coins are stuck to the ends of the pole with superglue as this is enough to hold them in place.

Howzat ?:D
 
Ah ! I have just thought of something further...

IF...the drilled coins were absent...in theory...and...in practice, the centres (which in this case are just wood screws) would serve to wear a bigger hole in each end as the work was rotated, therefore inducing sideshake and endshake more quickly, and therefore requiring frequent tightening because the wood is "soft", whereas when tunring metal between centres this problem is existent but not acute. When turning metal between centres these have to be lubricated otherwise wear will occur both on the centres and the metal being turned. Even 1/500 of a millimetre in precision work is relevant, but not for turning a flag staff. Howzat ?:D
 
I don't know if anyone has already pointed this out but, unless you are planning to take up chair bodging, the amount of time taken to construct a pole lathe will be far more than the time taken to create a new flag pole using saws, planes and spoke shave. This is surprisingly easy and quick if you're careful. Just get a suitably sized blank, plane the corners off to make an octogan, the plane the corners off again to make a sixteenogan, round off with a spokeshave and finally sand to a smooth finish.
 
VO5 said:
Howzat ?:D
Click to expand...

Much better - what wasn't clear before was that the centres were simply woodscrews. You'd said the points were "on screws", but I took that to mean they were fitted with some kind of adjusting mechanism. I was imagining a substantial cone like the tailstocks on the metal lathes we had at school.

Pete
 
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Great post this is.
Next week we are going to look at making your own bowls and crockery with a simple potting wheel!!
 
ghostlymoron said:
I don't know if anyone has already pointed this out but, unless you are planning to take up chair bodging, the amount of time taken to construct a pole lathe will be far more than the time taken to create a new flag pole using saws, planes and spoke shave. This is surprisingly easy and quick if you're careful. Just get a suitably sized blank, plane the corners off to make an octogan, the plane the corners off again to make a sixteenogan, round off with a spokeshave and finally sand to a smooth finish.
Click to expand...

I see merit in this method because it is a planned reduction. I am going to do it. Thanks for the tip. Makes sense.
 
ghostlymoron said:
I don't know if anyone has already pointed this out but, unless you are planning to take up chair bodging, the amount of time taken to construct a pole lathe will be far more than the time taken to create a new flag pole using saws, planes and spoke shave. This is surprisingly easy and quick if you're careful. Just get a suitably sized blank, plane the corners off to make an octogan, the plane the corners off again to make a sixteenogan, round off with a spokeshave and finally sand to a smooth finish.
Click to expand...
That's more or less how I made ours, although I had access to a bandsaw to take off the first corners and make the octagonal blank. Then I tapered the octagonal by planing first the "odd" flats and then the even ones. So after planing the odd flats you have a stall that's still octagonal at the base, but square at the tip. Next planing operation on the other flats makes the tip octagonal again.
 
gandy said:
That's more or less how I made ours, although I had access to a bandsaw to take off the first corners and make the octagonal blank. Then I tapered the octagonal by planing first the "odd" flats and then the even ones. So after planing the odd flats you have a stall that's still octagonal at the base, but square at the tip. Next planing operation on the other flats makes the tip octagonal again.
Click to expand...


Now I have got to the octagonal stage.
At each end I have painted with white typing correcting fluid and made an ink circle with a compass. All the flats are tangential to the circles.
Now I am going to make a smaller circle at one end for the taper that I will start at one third up. Then we'll see. Many thanks to all of you for your help and advice so far.:D
 
Nope....not yet.
I have realised (and this is very basic geometry) that the octagon, for it to be perfect, has to have eight sides which are equal.
As the flagstaff will have a taper, so proprtionately these flats have to be equal all along. Otherwise, the flagstaff will not come out straght as I want it, like a billiard cue, So more work is required. I will keep you posted.
Perfectioist that I am, I will persist.:eek:
 
VO5 said:
Nope....not yet.
I have realised (and this is very basic geometry) that the octagon, for it to be perfect, has to have eight sides which are equal.
As the flagstaff will have a taper, so proprtionately these flats have to be equal all along. Otherwise, the flagstaff will not come out straght as I want it, like a billiard cue, So more work is required. I will keep you posted.
Perfectioist that I am, I will persist.:eek:
Click to expand...
That was the problem I addressed with the sequence of planing. If all the flats are the same size at the end, then the taper is centred, assuming it started accurately squared. In my case the square stage was accurate, and diagonal cuts were each the same so even though it was not a perfect octagon then all the square faces matched as did all the diagonals.

It's hellish explaining this isn't it? Much easier to see and do than to put in writing.

I think the spar gauge doesn't create the taper, but just honours it, so would work if you had a correctly tapered square section and wanted to mark it for the octagonal stage.
 
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