RETIRED
24th February 2011, 05:41 PM
I was contacted by Jim Carroll who wanted some big gate posts to make a statement.
Perhaps he is opening a winery now?:D
After going through my pile of phone poles and logs we decided on an Ironbark pole that had been up since 1935.
The dimensions were 250mm diameter by 2900mm long.
The drawing.
162431
It must have been a post on a corner because it had that many nails in it you could start a foundry.
After cutting to length we bought them in and put them on trestles to denail them.
162422162423
The pole ID plate gives timber type and date of erecting.
162424
The next part is centering. We use a disc, a centre punch and a hammer.
This is then marked with a wax crayon.
162433
Using block and tackles we then position the blank in the lathe with the biggest (or heaviest end) at the head stock and lock it in.
This is checked and rechecked about 3 times.
Speed and direction of rotation is checked also.
You don't want one of these bouncing off your chest.
162434
When all this is done, the slings are released, the piece turned by hand and the tool rest put in place. We try to use a one piece rest as it makes getting flowing lines easier than if you have to move smaller rests all the time but we do use them. See later.
162435
When everything is set, anyone within the firing zone is cleared and the lathe started remotely on the right hand side.
Whilst the log is rotating I keep my hand on the switch to shut it down immediately should any thing happen.
If all is good it is switched off and all locks are checked again to make sure that nothing has vibrated loose.
The speed at starting is 320 RPM in this case. Sometimes we have to start at the lowest setting. 57 RPM.
I start to get the log round now by removing the waste.
162436162437
When the log is close enough to round the speed is increased to 420 RPM.
162438
This is the speed it will remain at until finished.
Once it is round I look for the narrowest point ABOVE where it will go in the ground.
I use the Ci1 rougher as a parting tool and get the log perfectly round at that point.
Note the reference point on rest in white. All measurements will be taken from this point. This is the bottom of the post.
162439
I then measure this with calipers and note the size. I write this on the tool rest with a white paint pencil.
162432 162490
Using the calipers and the parting tool I mark out reference sizes about 600mm apart down the log.
The calipers are set about 5mm larger than finished size to allow for smoothing cuts and sanding.
162440
Once these are in place we "join the dots" or in this case the grooves to get the post down to size.
Once we have that done, the lathe is stopped and I run the calipers over the whole post marking high spots with a crayon.
162442
We start the lathe up again and take them out with smoothing cuts using a large gouge.
162443
This is the difference between a roughing cut on the left with a smoothing cut on the right.
162444
One parallel log ready to mark out.
162446
If we don't have actual dimensions to work to (it happens a lot) I use experience and the drawing to get the balance right on the post. You have to remember that a post looks totally different vertical than horizontal.
After I have penciled in the lines at the details I sometimes stand on the lathe or turn my head sideways to envisage what it will look like standing up.
I then mark the tool rest with that white marker and write what the detail is. It is easy to put a cove in where a bead should be. Disastrous is the best description.
That way you end up with 2 reference points after the 1st one.
162497
I then mark the post with a skew chisel. I do this for a couple of reasons. It gives a visual reference that something goes there and when you have to part in there is no tearout at the edges so keeping them sharp.
162447162448
If the post has enough bulk I will part out where the coves are going next. On smaller diameters I will do the beads first to keep the strength in the post until the last moment.
162448162455
I use a long and strong detail gouge (old style) for doing the coves.
162457
With the coves done I cut the beads next with a traditional spindle gouge ground to a thumb nail shape.
162462162463
With the coves and adjoining beads done I clean up the fillets with a skew.
162458162459
With those done I run the taper.
162460
Now I move up the post and do the top.
Where the bead meets the straight cylinder it is too tight to get a gouge or skew chisel in so we resort to something else.
We start the cut with a normal gouge but finish with a narrow detail gouge with a lady finger grind on it.
162461
Getting near the end now. You will note that I have not reduced the post in size any more than necessary at the head stock. The old posts that we turn can quite often have cracks that will allow the post to snap out of the drive spur.
162464
Again it is an anal clenching moment if that happens not to mention annoying.
If it looks like breaking we can put a steady in to support the post while we hasten slowly.
At about this point we sand the post starting with an angle grinder and in this case hand sanding to 150# as these are being painted.
162465162466
After sanding, the long rest is slid to one side and a small rest used to get in close to the final part. This is turned and sanded.
162467
The first one done.
Whist working we sharpen the chisels about every minute. The grinders are not switched off.
162430
Round 2
Next post in.
162468
Normally we put the completed post behind as a pattern and reference for turning the next so that we can get curves and details the same.
Because it is so big we have to have it overhead.
162469
And so it begins again.
Sorry about being so long.
Perhaps he is opening a winery now?:D
After going through my pile of phone poles and logs we decided on an Ironbark pole that had been up since 1935.
The dimensions were 250mm diameter by 2900mm long.
The drawing.
162431
It must have been a post on a corner because it had that many nails in it you could start a foundry.
After cutting to length we bought them in and put them on trestles to denail them.
162422162423
The pole ID plate gives timber type and date of erecting.
162424
The next part is centering. We use a disc, a centre punch and a hammer.
This is then marked with a wax crayon.
162433
Using block and tackles we then position the blank in the lathe with the biggest (or heaviest end) at the head stock and lock it in.
This is checked and rechecked about 3 times.
Speed and direction of rotation is checked also.
You don't want one of these bouncing off your chest.
162434
When all this is done, the slings are released, the piece turned by hand and the tool rest put in place. We try to use a one piece rest as it makes getting flowing lines easier than if you have to move smaller rests all the time but we do use them. See later.
162435
When everything is set, anyone within the firing zone is cleared and the lathe started remotely on the right hand side.
Whilst the log is rotating I keep my hand on the switch to shut it down immediately should any thing happen.
If all is good it is switched off and all locks are checked again to make sure that nothing has vibrated loose.
The speed at starting is 320 RPM in this case. Sometimes we have to start at the lowest setting. 57 RPM.
I start to get the log round now by removing the waste.
162436162437
When the log is close enough to round the speed is increased to 420 RPM.
162438
This is the speed it will remain at until finished.
Once it is round I look for the narrowest point ABOVE where it will go in the ground.
I use the Ci1 rougher as a parting tool and get the log perfectly round at that point.
Note the reference point on rest in white. All measurements will be taken from this point. This is the bottom of the post.
162439
I then measure this with calipers and note the size. I write this on the tool rest with a white paint pencil.
162432 162490
Using the calipers and the parting tool I mark out reference sizes about 600mm apart down the log.
The calipers are set about 5mm larger than finished size to allow for smoothing cuts and sanding.
162440
Once these are in place we "join the dots" or in this case the grooves to get the post down to size.
Once we have that done, the lathe is stopped and I run the calipers over the whole post marking high spots with a crayon.
162442
We start the lathe up again and take them out with smoothing cuts using a large gouge.
162443
This is the difference between a roughing cut on the left with a smoothing cut on the right.
162444
One parallel log ready to mark out.
162446
If we don't have actual dimensions to work to (it happens a lot) I use experience and the drawing to get the balance right on the post. You have to remember that a post looks totally different vertical than horizontal.
After I have penciled in the lines at the details I sometimes stand on the lathe or turn my head sideways to envisage what it will look like standing up.
I then mark the tool rest with that white marker and write what the detail is. It is easy to put a cove in where a bead should be. Disastrous is the best description.
That way you end up with 2 reference points after the 1st one.
162497
I then mark the post with a skew chisel. I do this for a couple of reasons. It gives a visual reference that something goes there and when you have to part in there is no tearout at the edges so keeping them sharp.
162447162448
If the post has enough bulk I will part out where the coves are going next. On smaller diameters I will do the beads first to keep the strength in the post until the last moment.
162448162455
I use a long and strong detail gouge (old style) for doing the coves.
162457
With the coves done I cut the beads next with a traditional spindle gouge ground to a thumb nail shape.
162462162463
With the coves and adjoining beads done I clean up the fillets with a skew.
162458162459
With those done I run the taper.
162460
Now I move up the post and do the top.
Where the bead meets the straight cylinder it is too tight to get a gouge or skew chisel in so we resort to something else.
We start the cut with a normal gouge but finish with a narrow detail gouge with a lady finger grind on it.
162461
Getting near the end now. You will note that I have not reduced the post in size any more than necessary at the head stock. The old posts that we turn can quite often have cracks that will allow the post to snap out of the drive spur.
162464
Again it is an anal clenching moment if that happens not to mention annoying.
If it looks like breaking we can put a steady in to support the post while we hasten slowly.
At about this point we sand the post starting with an angle grinder and in this case hand sanding to 150# as these are being painted.
162465162466
After sanding, the long rest is slid to one side and a small rest used to get in close to the final part. This is turned and sanded.
162467
The first one done.
Whist working we sharpen the chisels about every minute. The grinders are not switched off.
162430
Round 2
Next post in.
162468
Normally we put the completed post behind as a pattern and reference for turning the next so that we can get curves and details the same.
Because it is so big we have to have it overhead.
162469
And so it begins again.
Sorry about being so long.