Whoa - look at this - a blog entry!
Recently I made a couple cryptexes (not sure what the plural of cryptex is). I followed directions written up by one of our local club members, and also looked up some directions given a few years ago in the American Woodturning Journal, the magazine published by the American Association of Woodturners (AAW). I am publishing these observations in the hope that it may proove helpful to someone trying this process for the first time.
Instructions from Glenn ? - MAWT member with modifications to put statements into the active voice - comments in courier.
The first step in making a cyptex is to pick the code for the box and write it down.
Trust me, you don’t want to forget your code half way through the project.
The number of characters in your code determines the number of dials you need to make. For this example we will use MAWT (Milwaukee Area Wood Turners).
1. Mount your blank in the chuck and clean up the end grain. Make sure to leave a dimple in the center whenever you clean up the end grain to help start your drill bits.
2. Use a 1 ½” forstner bit to bore out a hole deep enough for all of your dials. I usually go ½” per dial plus an extra ½” to make sure everything clears. True up the inside with a box scraper being careful to keep the walls parallel. If you have a cone shaped live center, bring it up to help stabilize the piece while you turn the outside of blank down to 2” diameter. Sand to desired finish with a flat block to ensure outside is really flat.
3. Use the index wheel in your headstock to divide the cylinder into the number of letters, numbers or symbols you want on each dial. Draw a line for each indexing with a soft pencil along the outside using your tool rest for support. Now when we part off the dials each will be divided the same. With a spindle gouge clean up the end of the opening and give it a slight back angle. There are 26 letters in the English alphabet (duh). My lathe divides into 48 or 24 or 12, etc. Therefore, I divide the dials into 24 and drop 'Q' and 'X' out of the alphabet.
4. Use a 1 ¾” forstner bit to bore a 1/8” recess into the end of the cylinder. This can be a bit deeper than 1/8, as much as 3/16 inch - this is the counter bore for the pin that allows the ring to rotate around it when the box is closed. Sand and clean the inside. Measure 3/8” from the end and make a line around the cylinder. Part the piece off at this line while giving the part a slight forward angle. Use a rasp or sandpaper around a dowel to clean any frayed or torn fibers. You have just turned your first dial.
5. Now repeat these steps until you have enough dials to make your code. For each dial, clean up the end of opening and giving it a slight back angle. Number the inside of each dial with a pencil, as you part them off. This is important. I place the number on the side of the dial - it needs to be visible until the final assembly of the cryptex.
6. Burn or mark your dials with the letters, numbers or symbols that you want to use. I prefer to burn the letters because it is more durable and it will be handled a lot. After burning, lightly sand the dial to remove the pencil lines. This also cleans up some of the scorching that comes from burning. Then apply finish inside and out. I have been using Minwax wipe-on poly as it dries fairly quickly and adds very little build-up that can affect the dimensions of the piece.
The Back Bone:
1. Put your blank in the chuck and clean up the face.
2. Use a 1 1/8” forstner bit to bore a hole as deep as the code rings are tall when stacked, then add another ½”. True up the inside with a box scraper and sand.
3. Use the cone center again, and turn down the outside until it is the same diameter as the inside of the dials you made. Make the outside of the cylinder as long as you bored out the inside plus another ½”. Sand the cylinder with a wood block to ensure its flat. Stop when the dials slide on smoothly over the tube. Take your time with this step as it is critical to a nice fit of the dials to the back bone - the dials must turn smoothly around the back bone, but should not be sloppy.
4. Apply finish and use your indexer to draw a single line down the center the full length of the cylinder with a soft pencil. If you have more than one chuck leave the blank in the chuck and set it aside. If not, remove from chuck and prepare for the next step. If you need to remove the back bone from the chuck, mark the back bone so it can be reinstalled in the same position in the chuck.
1. Put a blank in the chuck and clean up face.
2. Use a 7/8” forstner bit to bore a hole the same depth as the height of all the code rings stacked together, plus another ¼”. Sand and finish the inside.
3. Use the cone center again, and turn down the outside of the box to the same diameter as the inside of the Back Bone and as long as the dials are tall plus 1/8”. Sand until it smoothly slides into the Back Bone and then apply finish. Note: The shoulder of the blank should be back beveled a hint and finished at this time. To make things easier we will refer to this as the base of the box because it will eventually be turned into the base or one end of the actual box. Thus we will name the opposite side of the box as the “top”, which is the side the Back Bone is on.
1. Now take the dials and slip them over the Back Bone. Make sure the number 1 dial goes on first with the recess facing the chuck. Then slide the Box into the Back Bone and press them together. I use a clamp to make sure the two pieces don’t move apart. I do this on the lathe and use pressure from the tailstock to keep the pieces from turning within each other. The article in the American Woodturners Journal drills these holes on a drill press, but I have not found this to be necessary.
2. Press your last dial up against the shoulder of the Box/ base and make a gap between the last dial and the second to last. Mark the Back Bone at the inside edge of the recess with your (sharp) soft pencil. Place the mark across the pencil line that runs the length of the box (Step 4 under Back Bone). Repeat for each dial then remove the dials.
3. Slide the Box back into the Back Bone and re-clamp them to keep them from moving apart.
4. Use a 1/8” brad point drill bit to drill down through the sides of both the Back Bone and Box pieces. You can measure the distance and remark the cross marks on the Back Bone 1/16” toward the Back Bone shoulder. I prefer to just put the outer wing of the brad point on the existing lines and rock the point into the wood. The point is that you are making the holes for your pins, these pins ride in the recess of the dials until the combo is achieved, therefore the holes have to be entirely to side of the pencil cross points. The “top” side. Drill your holes as vertical as possible.
5. Remove the Box from the Back Bone and clean up any splintering that may have occurred.
6. Mount the Back Bone in a vise and use a dovetail saw to cut a slot from the open end of the cylinder to the last pin hole and no further. This slot allows the pins that will be mounted in the Box to slide through the Back Bone and dials. Therefore, the slot has to be at least as wide as the pin holes you just drilled. So use the pin holes as a guide for your saw kerfs. If anything a little too big is better, just in case the pins are not perfectly perpendicular to the box. Clean up with a rasp and sandpaper for a smooth finish.
7. Re-mount the Back Bone on the lathe. Measure from the opening the depth as the code rings are tall plus another ¼” and draw a line around the cylinder. Part the Back Bone off to the left of the line as cleanly as possible. Clean up any fibers with sandpaper and set aside.
Top and Base:
1. Mount a blank of the same wood as the base / box and true the face, sand and finish. Make a recess a gnat’s ass deeper than ¼” and the same diameter as the Back Bone. Specifically the side that does not have the slot. This is the side that will be glued into the recess, but not now.
2. Reverse the blank and jam chuck it to the lathe and bring your tail stock up to support the chucking. Now turn the top to the design of your choice. The shoulder needs to be bigger around than the dials. Sand and finish the top and remove from lathe.
3. Glue the Back Bone into the recess and set aside.
4. Reverse the Box/ base and jam chuck it onto the lathe. Turn the base of the box to the design of your choice. Make sure the shoulder is larger than the dials and matches the diameter of the shoulder in step 2. Either a mirror image of the top or an actual base so the entire box will stand vertical when it is done. Sand and finish. Set aside.
1. Pins are nothing more than 1/8” brass rod that you can get at the box store for a couple of bucks. You can hack saw them to size and smooth with a file or sander. I prefer to cut them to two inch lengths and put one in a Jacobs chuck on the lathe. With the lathe on I use a file to round over the lead edge until its bullet shaped. Then using a dial caliper I measure how tall I need the pins and then transfer that mark to the brass with the sharp tips of the calipers. Then I just use a skew to part it off. Repeat until I have a few more than I need. I line them up and see if I need to adjust any with a file before I superglue them into the holes we drilled in the Box making sure they are all the same height. Always dry fit them before adding the glue as more often than not you will need to file them to slide into the holes.
Remember that piece of paper you wrote your combo on? Dig it out. You will need to make a notch into each dial that corresponds to the combo you chose. If you numbered your dials as they were parted off, then your first dial is your first letter. In our case dial 1 is M, dial 2 is A, dial 3 is W, and dial 4 is T. The notch has to let the pin through so it has to be at least 1/8” wide and as deep as the pins stand above the Back Bone when slid together. I use a rat tail rasp and cut out a groove as deep as the recess inside, making sure I am doing this right behind the letter representing that dials combo.
1. It is very important to dry fit all the parts before final gluing to make sure everything moves freely and smoothly.
2. Slide the dials onto the Back Bone/ top with the recess side facing the shoulder.
3. Slide the Box/ base inside the Back Bone turning the dials to allow the pins to slide home. This should make the dials spell your combo.
4. This is a good time to mark the top and/ or bottom where the code lines up on the pins so that when you dial the combo later you know where it should line up to work.
5. Spin the dials and make sure they move smoothly. Dial your combo and make sure you can extract the box without pulling the dials off. If you have a problem with any of these you will need to find where things are binding and finesse them with a rasp or sandpaper.
6. Only when it passes these tests should you assemble the dials on the Back Bone and glue the last dial to the Back Bone itself. These will permanently hold the dials on the Back Bone and up against the shoulder of the top. Since you can’t move the last dial you must glue it so the slot of the Back Bone and the notch of the dial line up allowing the pins to pass.
7. Note: I like to use the Beall buffing system and buff all the pieces before final gluing. It gives everything a smooth polished feeling and nice sheen.
Congratulations, despite everything I told you might actually have a working Cryptex. If not, blame the demonstrator and start over.
Updated 26 September 2014
(Mouse over the view above for an end view).
A couple weeks ago I started putting together a captured hollowing rig. I had seen one demonstrated a last year at our turning club and even had a chance to operate it for a few minutes. I have been doing more hollowing lately and had some failures. And, at least one of my successes was a qualified success in that the wall thickness of the turned piece was pretty thick and the piece was too heavy when it was completed.
There are a number of types of systems out there but right or wrong, I decided I could build the captured style.
There are a number of descriptions of building rigs on the internet. In none of them did I find a materials list, so here is mine:
|3/4 round cold rolled steel bar
|this is divided into the following:
|straight handle piece
|piece to bend into a D for the handle
|1x1x1/8 steel angle iron
|cut in two for the backrest
|1x1x1/8 steel angle iron
|Welded onto the upright support and the lower backrest angle is bolted to it
|1.25 inch square x 0.120 wall tubing
|the (lower) upright on the backrest support - welded to plate (below)
|1 inch round x 0.120 wall tubing
|the (upper) upright on the backrest support. Slides up and down in the square tubing to adjust backrest height
|6x1/4 Steel Plate
|the backrest support (the piece that clamps to the ways)
|3 to 4 inches
|1-1/4 OD tube with 1/4 inch wall thickness
|the coupler between the handle and the boring bar
|of 3/4-inch tubing
|the laser arm and upright
|Guide cutting tool and control wall thickness
|3/8 inch rod
|this is cut into 3 inch pieces to mount cutters
|3/16 inch square tool bits
from Ace Hardware w/ 3/8x16 thread
|Adjust backrest height.This could be made form a 38x16 bolt with a shop-made nut or a bit of rod welded to the head, but this was easier and looks nice.
|3/8x16 NC Nut
|Weld over hole in upright to thread Knob into
|1-inch round bar
|to be cut rounds to make swivels
|5/16 x 3-1/2 inch carriage bolts (threaded to head)
|Supports at ends of backrest angles
|5/16 NC Nuts
|Supports at ends of backrest angles
|5/16 flat washers
|Supports at ends of backrest angles
|5/16 NC Coupler Nuts
|Supports at ends of backrest angles
|1/4x20x1/4 Set Screws
|Retain boring bar into coupler and swivel mounts into boring bar
|10-32 Button Head Capscrews
|Retain swivels to swivel mounts
|Washers for the 10-32 Button Head Capscrews
|Retain swivels to swivel mounts
|5/15 NC T-nut - brad retained style
|For the backrest clamp.
|5/15 NC x ?? Capscrew (bolt)
|For the backrest clamp. The length of this bolt depends on the depth of the ways on your lathe. I used a 1-1/2 inch bolt which is plenty for my lath as the ways are only 1/2-inch deep.
|Miscellaneous hardwood scraps
|Laser mount and fittings
Requires access (or friends with access) to the following tools:
|Metal Mill or milling attachment for metal lathe
|Mill slots in swivels for cutting tools (Swivel can be purchased from Monstor Tools or Lyle Jamiesen)
|Taps - 1/4x20 and 10-32
|Tap set-screw holes and swivel mounts
|OxyAcetylene torch or equivalent
|Any time I weld I need a grinder
|Sawzall with metal cutting blade
|Quicker and easier than hacksaw
|3/4 to 1/14 wide Mill File
|Smoothing, dimensioning, fitting...
|3/4 metal drill bit
|Drill/ream out inside of 1-1/4 OD coupler to allow Boring bar to slip into it. You may also be able to use this to make the laser tube fittings
Here is how I did it
Above - a close-up view of the backrest - shows the adjustment knob, and also the clamp knob. Also shows how the upright is welded to the backrest support angle, and how that angle is bolted to the bottom angle of the backrest. The two washers between the backrest support angle and the bottom backrest angle are to level the backrest due to a poor job of welding.
Above - shows how the two backrest angles are fastened together. I used bolts that were threaded to the head. I ground the corners off the squares on the carriage bolt heads and capture each angle between either the head or a standard nut and the coupling nuts. This reduces the need for welding, plus lets you adjust the fit of the angles to the D-Handle.
Above pictures shows how the upright is welded to the plate and also how the adjustment knob fits into the upright. IF I do another one I will use round tibing for the inside upright for two reasons. It will make it less critical to have the upright square to the plate and also reduce the need to accomodate the seam inside the squre tube for telescoping action.
Above shows how the T-nut is retained to the backrest clamp. Also shows shop-made knob for the backrest clamp.
Above shows what I call the cross-clamp for the laser upright. It is made from an ash block approximately 2 x 3 x 2-1/2. The clamp is made by drilling a 3/4-inch hole all the way through the block and then drilling a hole into the block until it meets the through hole. Then a blind hole is drilled for the upright. I then sliced the block on the bandsaw through the centerline of the through-hole and the cross hole. I drilled 4 pilot holes in the bottom of the block and used wood screws to clamp the block to the D-handle.
At the top of the upright is what I call a T-Clamp. This piece is made from Siberian Elm. The screws you see are blunted wood screws used for set screws in the event there is any movement within the clamp.
The above is not a terrific picture. This is where the laser is mounted to the end of the laser arm. I will very likely be rebuilding this piece. For now, the hole for the laser is countersunk very slightly at the top of the hole. To turn the laser on I push it down so the large diameter part of the hole presses on the button for the laser.
This is the first piece turned start-to-finish on the new lathe that I posted about last week.
This box is from spalted sycamore that came from a tree surgeon near Madison, WI. I got the wood in late 2011 - 2-1/2 years ago.The wood is really quite nicely spalted. Also, I really like the grain in sycamore, and this box shows off a little bit of that grain in this first picture.
Here is the other side.
And the top.
Finally, a view of the inside.
I drove over to Barneveld last Monday and picked up my new American Beauty lathe. After talking to Brent and Deb I decided the best option was to pick it up fully assembled so I took my trailer over behind my 2004 F150.
To secure it to the trailer I screwed some 2x4s down to capture each leg, and then tied it down with some ratchet straps.
I was bent over the end of the trailer driving screws into one of the 2x4s when I felt something move in by back. CRAP!! It wasn't as bad as sometimes but it hsn't been fun, either. As soon as we started rolling towards home my wife called the chiro on the cell phone and made me an appointment for this afternoon. This is me from the rear after a visit to the chiro, an Aleve and about an hour on the ice pack.
My wife says I normally stand up straighter than this.
The challenge after we got it 'home' was to get it into the shop.
So I dropped the trailer off the truck and hooked it to the tractor, and backed it up to the shop door.
I raised the hitch on the tractor as far as it would go.
But, I still lacked about 6 inches of having the back end of the trailer on the ground. So I thought getting the weight of the lathe behind the axle might help.
So I screwed a couple of the 2x4s to the back of the trailer to loop a come-along cable around, put a 4x4 across the other end of the lathe and stared moving it backward.
Until the legs of the lathe hit the metal lip on the rear edge of the trailer. I levered the legs up over the lip and created a couple little ramps from 2x4s to slide the legs up over the lip which sticks up above the floor of the trailer about 1/2 inch.
This served to get the rear legs over the end of the trailer and down to the cement pad that is in front of the shed door.
However, about the time the rear legs of the lathe hit the cement, I ran out of room for the come-along. That puzzled us for a little bit, so we came up with running a chain through the shop,
to a ratchet strap,
to another 4x4 across the rear door of the shop.
Also, we could now put a floor jack under one end of the lathe and steer it a little bit.
So we got it into the shop and unwrapped the plastic from around it, and looked it over. One of the disadvantages of bringing it home 'al fresco' is apparently a little bird used it as a temporary roost - that white spec you see below is bird poop. Also, we ran through some light drizzle on the way home, just enough that I will need to wipe the paint down to get water spots off it.
It's in the shed and out of the rain (we're getting thunder and lightning as I write this). Tomorrow, or whenever my back feels up to it, we will shove it back into it's permanent home, which will be in the corner where the bandsaw now is. I think I am going to try to get the OSB painted before I do that, and I need to change the plug where I have the bandsaw plugged in so I can plug the lathe into that outlet.
On Tuesday morning I got the walls painted in the corner where I want to put the lathe. Here is the wall with the first coat of paint drying.
Then later I got the lathe shoved, pulled, pushed, moved - whatever - back into that corner.
And, yes, I have even managed to make a few shavings with it. I even have a piece that I completed start to finish on it, but I don't have a picture yet because the poly is drying on it.
I turned the dust collector a quarter turn and moved the band saw to where the Nova sat.Those are in the background behind the tool cart and the Nova lathe which is pulled out from the wall.
I also mounted a shop light over the lathe and screwed a 1x2 to the wall to give a little extra support to the screws I drive into the wall to hang tools from
Here are a couple pictures of my tool cart (for the lathe). I cobbled this together in a fit of frustration one day last year, but it serves me well for the most part. If I could just learn not to pile on it every little thing that comes to hand.
Once we have a log all cut up we need to rough turn and seal the bowls. We start by cutting them round on the band saw. This step is not entirely necessary, but it makes rounding the blank on the lathe much easier.
I have a number of rounds cut out of thin particle board and plywood. I can set a round on a bowl blank that has been cut out of a log and get an idea of the size of a bowl that I can get out of that log.
Once I have selected the round pattern piece, I screw or nail it to the bark side of the wood and use it as a guide to cut the blank round on the bandsaw.
I have rounds from 6 inches up to 15 inches.
Once i got the blank rounded I can mount it on the lathe.
I'm mounting this one between centers. I sometimes use a "woodworm" screw, which makes my lathe chuck into a screw chuck.
I start rounding the blank from the back.
The object is get a tenon turned on the back so I can turn it around and get it mounted in the chuck which is a more secure way of holding it.
Here is a close up view of the tenon turned on the back of the bowl blank.
The tenon has a deliberate dovetail shape on it that helps to hold it securely into the chuck, The chuck has a matching dovetail machined into it.
At this point, I am ony roughly shaping the bowl blank so that it can dry down for final turning some time in the future.
We turn the blank around and mount it in the chuck.
For the first part we use the live center to support the flat side of the bowl blank.
Remember that dovetail shaped tenon we put on the other side of the bowl blank? Here is the tenon securely gripped in the chuck.
We are looking here to see that our 15-inch bowl blank has "cleaned up" to about 13 inches.
This bowl is deep enough that we can core it out to get another bowl blank from the inside of the bowl. This has an added advantage of creating fewer wood chips to clean up.
The coring tool is a curved knife that cuts down into the bowl blank.
After we core the bowl and clean up the remainder of the wood a little, we seal the end grain on the bowl blank with a wax emulsion.
We seal the end grain of all the complete bowl blanks and the other pieces of the wood. The sealant helps to keep the wood from cracking. After the initial drying period for the sealant, we will set it on a shelf in the back barn. Once the bowl is rough turned, it takes three to six months for it to dry down to where it can be final turned.
I was recently offered some wood from a tree that was freshly cut. There have been a number of questions about what I do when I get the wood home. Here is what happens. In the photo below the two logs have been unloaded out of my pickup and carted back to my shed on the two wheel cart you see here.
I have three chainsaws that I can use to process logs - the electric one shown here is nowhere nealry large enough to process this wood, so we will use the Stihl instead.
Before we can properly process the wood we need to measure it out. This piece is a little over 16 inches across at the widest point.
And this first piece is about 23 inches long.
The other piece is about 29 inches long.
I didn't take pictures of the process, but I cut the shorter piece into three slices, one from each side and the pith is removed from the center of the log. We'll trim those pieces up later.
The longer piece I decided to treat a little differently. I cut it in two. The piece of bark lying across the log is an easy way to mark where to make the cut.
I found a little bit of a surprise when I cut it in two. There is a significant void through the enter of the log.
So I decided to see if I could divide it with the splittling maul.
The first piece split with one good hit.
The second piece took four or five hits before it gave way. I then used the chain saw to cut off those zig-zag edges to flatten them out.
I trimmed the ends off the pieces I cut off the sides of the shorter log.
So when all is said and done, I end up with 5 bowl blanks and a few other odds and ends that we will be able to do something with.
We'll close this segment with a picture of the scene of the crime - notice all the chain saw shavings on the ground.
We had two demos at our woodturning club this past spring that involved vacuum pumps. This wasn't the first time that a vacuum pump had crossed my mind, so when a oil-less pump came up on eBay for a reasonable price, and withing driving distance of the house, I bought it. That was the easy part.
To use a vacuum pump, I needed vacuum chucks. To make vacuum chucks, I needed face plates. I decided to make my own from some nuts and washers ordered from McMaster-Carr, and Industrial Supply house that sells over the internet. The nuts are threaded to fit the 1-1/4x8tpi threads on the headstock spindle
However, the nuts don't thread right up on the shoulder of the spindle, and the threads need to be undercut on my metal lathe to allow them to do so.
Once side of the nut (shown above) is faced, and is pretty square to the threads, but the other side of the nut is not square. I also wanted to cut a pilot on the nut for the washer to fit over when I welded it, so it turns into several steps to do everything that I need to do to make the face plate.
I put the known square side toward the chuck and surface off the side with the numbers on it. Then flip the nut over and undercut the threads. Finally, flip the nut back over and cut a notch in the nut to pilot the washer.
Once all that is done, I welded the washer to the nut.
Next, turn the nut back over and cut a notch in the nut to pilot the washer.Once all that is done, I welded the washer to the nut.
I'm not proud of my welds here - after talking to a friend at work, I think I need a new liner in my MIG gun.
Back side - hard to see the curvature of the seam while welding - almost guess work.
After the welding was completed, I ground off the extra weld material from the back side of the washer so the wood will sit up tightly against it. Then I made a simple jig with a couple screws to keep the distance from the edge of the washer consistent and drilled and countersunk a hole off each point of the nut.
I had some mahogany that was given to me by a friend a couple years ago that I cut into rounds. One of the pieces shown here was actually exchanged for a piece of maple that was large enough for a 6-inch(?) coupler. As shown above, I used the face plate that came with the Nova lathe for one of the chucks.
I screwed the wood to the face plate with hardened steel screws. I put generous bead of sealant between the faceplate and the wood. I realized that I had not drilled a hole through the center of the wood, so I put it on the drill press and drilled it out. On the other one I drilled out the wood before I screwed it down, but I like this method better so will likely do future ones this way.
I then mounted the roughed out wood block for the chuck onto the lathe and...
... turned to shape. I also opened up the hole in the center a bit.The next step was to cut a groove in the wood to insert a PVC pipe coupler. The mahogany disk received a 3-inch coupler and the maple disk received a 4-inch coupler.
The 4-inch chuck above is shown with a walnut natural-edge bowl is shown mounted on the chuck, being used as a jam chuck with the tailstock holding the bowl in place on the chuck.
With the chucks completed, it was time to turn my attention to the rotary vacuum coupler. The vacuum needs to be transferred (for lack of a better word) from the pump to the lathe, through the headstock to the chuck. The spindle of the headstock turns so a coupler needs to be made so the vacuum transfers from the stationary to the rotating part of the system. I used two sealed bearings for this that I bought off the internet from VBX Bearings (Google it).
I decided to make the coupler out of osage orange because it is a very stable and hard (dense) wood.
I drilled a 7/8-inch hole in the wood the depth of where I wanted the bearings to seat, then reversed the coupler in the chuck and drilled a 3/8-inch hole from the end into the bearing cavity.
I cut an o-ring groove around the end of the coupler and put a fat o-ring on it that I found at the hardware store.
I lose a little vacuum at the bearing end of the coupler, but there is very little loss of vacuum, if any, between the hole in the lathe end and the end of the spindle where the chuck screws onto the spindle.
Last winter, on a trip to visit my wife's sister, I spotted a bowl in her home that I was somewhat taken with. I have hd it in the back of my mind to copy the shape of that bowl ever since that trip.
For Christmas (or possibly a birthday) I had received a book entitled Woodturning Projects - a workshop guide to shapes. That book contained a bowl project with a very similar shape, but the bowl was designed to be turned end-grain and natural edge.
Over the Fourth of July break I had an opportunity to give it a try.
I had a little piece of walnut that I had laying around for several months. I thought it was dry, but after turning it it may not have been as dry as I thought.
I normally don't think of walnut as a hard wood, but this little piece of wood changed challenged that theory. It was very hard and slow turning. And although the wood seemed solid enough when I started turning it, some cracks developed in the wood as it neared its final form. I went ahead and finished the bowl anyway and here is the result.
It's a smallish bowl - about 5-1/2 inches in diameter and 2-3/4 inches high, including the foot.
I was able to use the vacuum chuck to hold the piece for turning out the foot and for final sanding.
I have an 18-inch RIkon bandsaw - model 10-345. After the junk bandsaws that I owned previously, I am very happy with it. I bought it because I wanted the ability to round bowl blanks of more thn 6 inches thickness. I purchased a wood-slicer blade for it from Highland Woodworking and have been absolutely amazed what it can do as far a slicing off a piece of wood at vernier thickness. And, that is with the standard fence, which if one reads the reviews on this saw, is deemed useless by common consent.
However, all is not perfect in this bandsaw paradise. The table insert for the blade on any bandsaw is prone to abuse. The table insert for this bandsaw seems to be particularly weak as the designer has placed a lot of holes in it - presumably for sawdust removal.
So on my last trip to the local Woodcraft store, I asked whether they carried the insert, and was pleased to find that they do. The price is $3.99 plus tax, which for this insert is a reasonable price. I can find them online for ~$16 for a pack of four, which does not include shipping.
However, based on the short life of the one that came with the saw, I am skeptical of the expected lifespan of the insert, and I am not impressed with the design, so I decided to try to make some from scrap stock.
First I had to determine the dimensions.
Thickness measures out to 0.191 inch - 3/16 is 0.1875 inch.
Diameter of the Rikon Insert is 2.761 inches.
I was a little leery of these dimensions (especially the diameter), so I thought it wise to measure the hole in the bandsaw table.
The diameter of the hole actually measured out to 2.75 inches.
And after a bit of finicky work - I had to loosen the blade a bit and open the covers - I determined that the depth of the counterbore is indeed about 0.193 inch.
Now that we have determined the dimensions, it's time to start making the inserts, I had a piece of maple stock that a friend had salvaged form a pallet.
Slicing 0.200 off the stock made it almost perfectly square, so slice we did. Notice the use of the stock fence. Also, I am using the 1/2-inch Woodslicer bladehere.
0.300 inch thickness off the bandsaw gives us plenty of thickness to work with - so on to the thickness planer.
It came off the thickness planer at 0.187. This is right at the limit of what my thickness planer will do.
Once I got the stock to the correct thickness, I used the actual Rikon insert to trace an oversized shape onto the stock.
I cut them out on my Craftsman bandsaw that I keep in the basement shop. This could easily be done on the Rikon as well. For me to do it effectively do it on the Rikon I would need to change blades, which is a bit of a task.
To round the inserts, I placed a waste block into the jaws of the scroll chuck on my Grizzly lathe, then drilled a hole for a screw in the center of the waste block.
I took one of the rough cutout inserts, and carefully found a center point and marked it. This only needs to be done with one of roughed out inserts, as once it is turned (rounded) it can b used as a pattern for the remainder of them. Then I drilled a hole through it and...
...and used a pan-head sheet metal screw to screw it to the wasteblock. The picture above shows two inserts being rounded at once. I only did one the first time, partly because, as I said above, you will want to use the first one as a pattern to mark the center for the remainder of them.
Also, the screw and inserts may not appear to be perfectly centered on the lathe. That's OK, because the purpose in this step is to make the insert perfectly round and the correct size - not to have the hole perfectly centered. You will find later that the hole pretty much disappears, anyway.
I use a skew chisel to round the inserts, taking off a little and measuring repeatedly until they are at the correct size.
Again, I used the Rikon insert as a pattern to mark the insert. For the slot, I marked it so the the grain runs across the slit made for the bandsaw blade. One thing worth noting, here, I did not extend the slot as far back into the insert as the standard Rikon insert. This saw will accept a wider blade than the 3/4 inch blade that is on it, so you can cut the depth of the slot to fit the blade you are using.
For convenience sake, I sawed these out on the craftsman bandsaw. I sawed the line and then sawed a second pass right beside it to effectively make a double-width kerf to give the bandsaw blade a little room to work.
Now, all that is left is to the the newly made insert out and try it. I had made some of these for a saw that I had owned previously in which the blade did not run very close to the center of the insert. I was a little concerned about where the blade would run in these. After I put the first one in and turned the saw on, I could hear the blade running against the side of it. I flipped it over and it was clearing the blade. Even if I needed to saw another kerf down the insert, it is still a much narrower gap than the Rikon insert.
If your blade runs well off the the side of the center of the hole in the table, you can cut the insert as you install it into the table. Turn on the saw and CAREFULLY align the insert with the hole and move it back into the moving blade. Once the insert is in place you can use it with the slot toward the rear of the hole in the table. If the insert is not stepped, once the slot if cut, you can flip it over and put the slot toward the front of the table.
In the picture above, the slack is off the bandsaw blade, when the slack was removed and the blade started to run, it moved back into the slot some distance.
So - how much is your time worth - a couple hours on a Saturday morning, and I have 6 inserts ready for use.
We'll see how they hold up in actual use.