The second thing I turned on my new Powermatic 3520C Lathe was a nice
cherry hollow form.
I put a high gloss finish on this piece. Gloss sells. But, it made getting a good photo a real pain. To many reflections.
7-1/2" diameter. 7-3/4" tall. Cherry wood.
The blank was a little out of balance. But, it did NOT give me any trouble. My new Powermatic 3520C lathe, handled it, no problem.
Note: Full disclosure. I also have a big VB36 lathe that I use for most of my hollow form turning. Turning this hollow form on my new Powermatic 3520C was a "one off" kind of thing. I did it, to check out the new lathe and write this blog entry.
Here I am all suited up and all ready to go. Standing in front of my new
Powermatic 3520C Lathe.
For more info about my new lathe see "My New Powermatic 3530C Lathe Verses My Old Powermatic 3520B" blog entry.
I really like the color of the Powermatic Turning Smock that I am wearing. Over time I have owned a lot of smocks. I have found that the AAW Turning Smock is the best design for me. It is light weight, well ventilated, sheds wood savings easily and comes out of the washing machine, looking like new. However, I really hate the blue and other dark colors! The PM smock is the same design and fabric. Just a lot better color.
Well, there is one difference / problem. The PM smock zips on the left. Most men's clothes in the US and the AAW smock zip on the right. I had to purchase my own PM smock on the web. The $50 price is the same as the AAW smock. Shipping is not cheap.
Here is the cherry wood log blank that I started with. My silver 1 foot
ruler is on top.
The blank was roughly 10" long. The blank was a bit oval and thus the diameter was difficult to measure. Sort of 9" diameter.
You can also see that the blank had a big knot in the side from a branch. I really like the interesting grain pattern this added to the finished piece. See first photo above. However, it can make the piece hard to hollow when your hollowing tool bounces around due to the hard spot created by the grain around the knot.
You can also see I am driving the blank with my big gold drive center from Stubby Lathe USA. They are no longer available. If I wanted to purchase one today, I would have to go with a Elio-DR Safe Drive or Big Bite Chuck Spur. See my "Best Drive Center" blog entry.
You can also see that the chain saw cut on the end of the log was a bit off. It is not very square. This and the knot are going to make the blank out of balance when I turn the lathe on. See next photo.
I was pleasantly surprised to find my new lathe was able to spin this sort
of out of balance log at 500 rpm. Almost not problem. See the video at
right. Take note of the glass of water on the bed of the lathe.
The log was sort of out of balance due to the NON square cut on the end of the log and the bit knot. See previous photo.
I strongly believe that all lathes can be vastly improved by adding 200+ lbs of weight to a shelf on the bottom of lathe. This makes them run a lot more stable. In this video I have NOT added any weight yet. Thus I was not expecting it to be this stable.
I will be adding a shelf with 200+ lbs of weight to this lathe. I have already done it. Stay turned for a future blog entry.
Note: One data point does not really prove anything. Your mileage may vary! I am sure my mileage will vary. Maybe the piece is not really all that far out of balance.
This photo shows how I moved the new movable control box for the lathe. While I was truing up the end of the log. I am getting ready to mount a face plate.
This photo shows the end of the log after I trued it up. I am getting ready to mount it on a face plate.
The new PM banjo that comes with the new PM 3520C is better than the old PM
3520B banjo. But, I still really do not like the offset design of the PM
I strongly prefer the NON offset design of the Oneway banjo shown in this photo. It allows me to get the banjo in there with out having to crank the quill in the tailstock way out. For more info see Oneway Banjo section of "My New Powermatic 3530C Lathe Verses My Old Powermatic 3520B" blog entry.
The stock PM tool rest is ok. But, it is to tall to fit in a Oneway banjo. PM make their banjos extra low to accommodate there tool rest.
The tool rest you see here is the one I prefer. It was custom made for me. It is very similar to the one I really love on my big VB36 lathe. I like my tool rests to be at least a 1/2" wide and almost flat on top so I can feel when my bowl gouge is straight across on top of the rest. I also prefer really beefy and strong tool rests. So there is absolutely no flex or vibration out near the end of the rest. Thus I like my rests to be made out of a 1/2" thick by 2" wide STEEL bar. With a 1" post that slopes off at 45 degrees, 3/4" of an inch below the top of the rest. With a really big and beefy weld between the post and steel bar. I like to have 4", 9" and 14" long tool rests for each lathe.
I do NOT like the Oneway tool rests or the Robust tools rests with the silly little round bar on top. "To each is own!"
This photo shows me attaching a Oneway face plate after truing up the end
of the blank.
I strongly prefer to use face plates rather than chucks. With proper screws they are the most secure way to mount something on the lathe.
I like to use #14 stainless steel sheet metal screws. I prefer square drive. www.mcmaster.com item #93945A071 for 1.5 inch long screws. I can easily drive the screws in with a Cordless Impact Driver. You can see my Makita impact driver in the background.
This photos shows the 3" PM face plate that comes with a PM 3520C
lathe, on the left. A Oneway 4" face plate is on the right.
The thin little crappy cast iron face plates that come with most modern lathes, are worthless. They will crack almost instantly if you really screw them down with decent screws. The PM face plate is thick and beefy. Thus it is ok. A big step above what comes with most lathes. I some times use it. But, for this size log the bigger 4" Oneway face plate is a better choice.
Here is the blank mounted on a face plate. Ready to turn.
I ALWAYS use the tailstock when possible for safety. It takes like 20 seconds to put the tailstock in place. Going to the hospital to get stitched up takes hours!
Here is what the blank looked like after I roughed it down to round.
I like to use a John Jordan 5/8" V Bowl Gouge to rough turn things. John's V shape is deep and wide open at the top. It just seems to work better than anything else I have tried. It cuts really fast and consistently throws a chip that I can easily aim to land directly in my trash can.
For more info see "My Modern Woodturning Tool Set" blog entry.
Here is what the blank looked like after I roughed in a shape.
I always start on the left. I remove a chuck of wood with a 45 degree angle cut this is big enough to get me back above the screws. This way I known, later when I turn my finial shape, the the bottom will NOT end up in the screws. Then I extend the 45 degree cut a little more to the right when my bottom shape will allow it.
I work on the right, after I get the left roughed in. I removed a chunk of wood on the right with a 45 degree angle cut when my top shape will allow it. Then I true up the top of the blank and make it a little concave.
I usually do this step using my Jordan 5/8" V Bowl Gouge.
Here is the finished outside shape.
I find that cutting the shape using the "wing" on a 5/8" Ellsworth Bowl Gouge works best. I cut the rim detail using my 1/2" Hosaluk Double Bevel Detail Gouge.
In the past, I would then shear scrape with my Ellsworth Bowl Gouge or an Al Stirt style shear scrapper. In really green wood, I have progressed to the point where I can now cut the outside shape cleaner using my 1/2" Hosaluk Double Bevel Detail Gouge. You can see in the photo that the surface is pretty good. I have NOT sanded it yet.
The finished piece ended up being roughly 7-1/2" in diameter.
You can clearly see in this photo that the pith ended up being off center. Some people would be upset by this. I have decided I really don't care. I just don't want the pith IN the rim. Anywhere else in the top, where it will get cut OUT, when I hollow is OK.
The pith regardless of where it is (on center or off center) in the bottom will always cause cracks. It will also, always cause some distortion in the rim. I don't really care. I have learned to love the distortion it adds. It makes each piece unique and more artistic.
I always drill out the center on my pieces using a 1" diameter morse
tapper shank drill. The drill mounts directly in the tail stock via the
morse taper shank.
Drilling out the center, establishes my inside bottom depth and makes the hollowing process a lot easier and faster.
The funny copper thing attached to the drill is my laser guide. It makes drilling the hole to the correct depth, fast and easy. A red laser points down from the green tip. It shows precisely where the tip of the drill is inside of the blank. You can not see the red laser beam in the photo. But you can see the red dot from the laser on the very tip of the drill if you look closely.
This photo shows my Hollowing Rid with TV Camera and TV Screen.
I ALWAYS hollow with the lathe running in reverse. Thus the cutter head in this photo is set up to cut on the right side.
I use a Trent Bosch Hollowing Stabilizer rig with a Rolly Munro cutter head.
I really love the Bosch Stabilizer. Because, it takes all the stress out of holding the hollowing tool level and it does not let the hollowing tool twist or roll over. However, It DOES NOT restrict my movement. I still have a tool handle, like on my bowl gouges and free hand hollowing tools. I can keep that tool handle up against my body, unlock my knees and use my body to hollow out a nice shape. Just like, I do when turning a bowl. Just like, I have practiced over and over again, while learning to turn a bowl. I don't like any of the other hollowing rigs (Jamieson, Elbo, Monster, etc) because they restrict my movement and I have to maneuver the tools using just my arms. I can't use my body.
I use a "Munro Hollower II" cutter head with a carbide cutter. I purchase the cutter head from Steve Sinner and supply my own custom 3/4" steel bar. I like the older "Munro Hollower II" rather than the new "Munro Wundercutt 10 Hollower". The new one does not work as well for this application.
I have created my own TV system. Finding the right camera is a HUGE problem. Thus I recommend people purchase the Trent Bosch Visualizer system. It is not cheap at $650. However, making your own system may approach this cost after a few miss steps, etc.
For more info on my hollowing rig see my “Carl’s TV Hollowing Rig” blog entry.
This photo shows the TV system in action. In the lower half, you can see
the Munro cutter head is just starting to hollow out the top of the piece.
Pointed to by magenta arrow in photo.
On the TV you can see part of the cutter head is exposed. The other part is represented by the blue line on screen. Pointed to by the blue arrow on photo.
The red line is my target wall thickness. Pointed to by the red arrow in photo. The red line is 1/4" away from blue line in real life down on the tool rest. Up on the TV monitor it is more like 1/2" due to magnification of TV camera and monitor.
The green arrow on photo points to the tiny TV camera.
My TV camera works best in low light. So I normally shut most of the overhead lights off. The bright light on the piece in photo is for the photo.
I draw the red and blue lines on the TV screen with white board dry erase markers. They did not show up well in my photo with the bright light for photo. Thus I enhanced them (redrew them) in Photoshop. I also added the red, blue, green and magenta arrows in Photoshop.
This photo shows the completely hidden cutter head represented by blue and
red lines on TV screen. The blue line is the outline of the cutter head.
The red line is my target wall thickness.
In the real world, after I draw the red and blue lines on the TV screen they ALWAYS move in sync with the cutter head. Because the TV camera moves in sync with the cutter head. i.e. the TV camera is always directly over and pointing down at the cutter head. Back up 2 photos to see TV camera mount. For more info see "Trent Bosch Visualizer" on YouTube.
In this case, I want my finial wall thickness to be roughly 3/16". Thus I have drawn the red line so it is 1/4" away from blue line. I will rough the wall thickness to 1/4" by going to the outside of the red line. Then. I will come back with a finish cut to the inside of the red line. The red line on screen is roughly 1/16" of wall thickness wide. Thus I will end up with a 3/16" finial wall thickness.
Note: I enhanced the red and blue lines in this photo in Photoshop.
This photo shows the inside of the hollow form after I have hollowed it out partially. The rim is pretty much finished. The side walls are still a little thick. The depth hole, I drilled in the center is still visible.
In this photo I am double checking the wall thickness with a $10 Jansjo LED
light from Ikea. The really bright part of the piece is the white sap wood
on the Cherry log. The darker part is the brown heart wood. The WET sap
wood always transmits more light than the heart wood.
Everything looks good here. I am done hollowing.
This photo also shows my normal almost dark lighting in the room. You can see on the TV screen that my TV camera is real happy with this level of light.
This photo shows the bottom cleaned up. Ready to be sanded and then parted
I used a bowl gouge to start finishing up the bottom. I removed any extra wood I left earlier to support the piece while hollowing. Then I sand.
This photo shows the piece after it has been sanded to 220 then buffed with
synthetic steel wood and a towel.
I started with a green (aka soaking wet) log. But, in this case, it was not to wet. Thus I got away with sanding and buffing it on the lathe.
First I sand with red 80 and 120 grit Sia Soft cloth & foam back sand paper from "Vince's Wooden Wonders". I use 9 or 10 3" x 4" pieces of Sia Soft. At first, each piece jams very quickly with a short of brown mush because the wood is wet. You get brown mush rather than saw dust. However, friction dries the SURFACE of the wood as you go. Eventually the sand paper comes away almost clean.
Then, I switch to 3" round Mirka AutoNet Mesh sanding disks from "Buff Daddy". I sand thru 120, 180 and then 220 grits. I never go beyond 220. I buff beyond 220! AutoNet is very similar to AbraNet made by Mirka. AutoNet is cheaper. Otherwise I can't tell the difference.
Then, I buff with Carl Ford Medium and Fine synthetic steel wool (nylon mesh pads, scotch brite pads, etc). I prefer the Silicon Carbide stuff that is for use on metals. I use it on wood. No problem. I get it from McMaster Carr, item # 4659A17 and 4659A18. Mcmaster calls it ulta, super dupper, extra fine or something crazy like that. I just call it medium and fine.
Finally, I buff with a blue Surgical Cotton Huck Towel from Amazon.
Another photo of the piece after it has been sanded and buffed.
The circular grain on the right is the knot from the branch. See photos at beginning. The white on the left is the sap wood. The brown is the heart wood.
This photo shows a jam chuck that is the perfect size for my stretch wrap plastic trick. Just a little smaller than the piece. See next photo.
This photo shows the piece being held on the jam chuck via stretch wrap.
This will allow me to finish the bottom with out a vacuum chuck. I try to avoid using my vacuum chuck system when the piece is wet green wood. Because, the vacuum sucks the water unevenly out of the piece.
You can purchase stretch wrap in 4" wide rolls from local office supply store.
This photo shows the piece after I removed the face plate and cut away the excess wood with a 1/2" bowl gouge. I like to use a 1/2" bowl gouge with an Al Stirt grind to remove most of the wood. I then use my 1/2" Hosaluk Double Bevel Detail Gouge to cut off the last little nib and finish up.
This photo shows why some people waste a ton of money on stupid stainless
steels ways for their lathe. They think this is rust. NO WAY! This is not
I was turning a nice green (i.e. wet) cherry log. The sap in a cherry log is a thin brown colored liquid. When you turn a wet cherry log on a lathe the sap comes flying out and lands on the ways. When it drys on the ways it looks like this. Yea, it may look like rust. But, it is not!
You can easily clean this mess off with a little WD40, a chunk of synthetic steel wool, and a paper towel. See next photo.
You have to clean this mess up EVEN if you have stainless steel ways! Yea, that's right! Stainless ways DO NOT stop the mess from happening! You have to clean the ways even if they are stainless. So why waste a ton of money on stainless?
Stainless steel ways cost big bucks. I can purchase a ton of WD40 for a lot less.