Keith Larrett

September 30, 2010

Cutting a Partial Sphere Safely

Putting the final touches on an install that I did recently, I had to cut some bun feet to size. The tile floor had been installed after the vanity cabinets, and the bun feet were now to tall to fit under the cabinet, about 3/8″ of an inch needed to be cut from the top of the feet.

The bun feet were not a complete sphere as they had a flat section. While I was able to put this flat section on the bed of my miter saw, the rounded section of the sphere was up against the fence. The potential for the piece to rotate as I cut it was high. As well as ruining an expensive fixture it could have caused a dangerous kickback. As expensive as the bun feet were, my fingers are worth more, so I needed to figure out a way to hold the bun feet so that the cut could be performed on my miter saw accurately and safely.

A couple of pieces of scrap wood screwed together made a jig which allowed just that. The bun foot is secured to the jig by a 1 1/2″ screw through the jig and into the base of the foot as well as an additional screw through the base of the jig and into the flat section of the bun foot These areas would be against the tile floor and the toe kick so the holes formed by the screw would be hidden after installation. The screws, as with the screws used to assemble the jig, would also be out of the way of the cut so the blade wouldn’t be damaged.

As you can see in the image below the bun foot is now held securely and square to the base and fence of the miter saw. There is no danger of the bun foot moving or rotating in any direction or axis. The jig also allows me plenty of room to hold it with my fingers far from the spinning blade.

The cut complete.

The bun foot installed.

Typically a miter saw, table saw and band saw are used to cut objects that sit flat on the bed and have a square edge that will ride against the fence. However, with the use of simple but effective jigs it is possible to cut round and irregular shaped objects. When designing the jig keep these points in mind:

The jig must be large enough to allow you to hold/guide it and keep your hands/fingers away from the blade.
The jig must hold the workpiece securely so there is no possibility of rotation or movement while performing the cut.
Any fasteners used to assemble the jig or hold the workpiece, screws, nails, clamps etc, need to be positioned so that the blade is not cutting into them.

Above all, if there is any doubt in your mind at all about the safety of the cut, then don’t make it. There is no cut that is worth bleeding over!

September 29, 2010

Lock-Rabbet Drawer Joint

A lock-rabbet joint, while not as strong as a dovetail joint, is still a strong, attractive and relatively easy joint to make. It is ideally suited for drawers. It can be made on either a table saw or router table.

As with much power tool woodworking, the time is in the set up. Once the set up is done, repeating the cut for any number of drawers is a quick process.

The first step is to mill your lumber. The picture below shows the pieces for one drawer box. The sides are 1/2″ thick maple, the front and back are 3/4″ maple. The length of the drawer front and back pieces is the same as the finished dimension of the drawer. The lengths of the drawer side pieces is half an inch less than the finished dimension of the drawer. As always, I have also prepared a couple of 1/2″ and 3/4″ scrap pieces to use for test cuts during the set up. It’s also a good idea to mark the outside face of each piece with chalk to avoid confusion.

With a 1/4″ dado blade in the table saw, cut a 1/4″ x 1/4″ groove down the side of each piece 1/4″ from the edge of the piece. This is the groove that will accept the drawer bottom, which is 1/4″ thick sheet material. Cutting the groove now gives you another visual aid as to which side is the inside of the drawer as well as which edge is the top and bottom.

Using one of the drawer sides as a gauge block, raise the 1/4″ dado blade to 1/2″ high. This is a rough adjustment and the blade height will be fine tuned in the next step.

The next step can be made by using a tall auxiliary table saw fence or with a tenoning jig as shown in the picture below. Using a scrap piece of wood and the blade at 1/2″ height, make a cut.

To confirm the blade is at the correct height, butt one of the drawer sides into the groove just cut. The drawer side should fit flush with the edge of the scrap piece, as in the picture below. If the drawer side is proud of the edge of the scrap piece, then the cut needs to be deeper and the blade should be raised. If the edge of the scrap piece is proud of the drawer side, then the cut is to deep and the blade should be lowered.

Now that the height of the blade is set, the distance from the tenoning jig to the blade needs to be set to 1/4″. I like to use a brass set up gauge for this.

With the outside face towards the tenoning jig, cut a 1/2″ x 1/4″ groove in the end of each side of the front and back pieces of the drawer.

Using either an auxillary fence on the table saw, or a piece of wood held with a fence clamp as shown, slide the table saw fence so that the piece of wood just touches the blade.

Lower the blade to 3/8″ of an inch.

With the outside face of the piece up, crosscut each end of the front and back pieces of the drawer.

The front and back pieces of the drawer are now complete.

Still using either a scrap piece of wood held by a fence clamp, set the height of the blade to 1/4″ and the distance of the blade from the scrap piece of wood to 1/4″. Then make a crosscut in one of the 1/2″ thick pieces of wood you prepared.

The astute among you will notice that I made a large block of wood to use as my “mini auxillary fence”. The one in the previous image did not reach all the way down to the table saw bed and made some set ups difficult.

The really astute among you will also notice that the position of the “mini auxiliary fence” in the shot below is far from ideal. Somewhere in the midst of making the new auxiliary fence, performing the cross-cut and then staging everything for the photo I had the auxiliary fence in the wrong position. My bad. Once the distance between the fence and the blade is established, the auxiliary fence should be moved back behind the blade, where it can perform it’s function as a stop block but not run the risk of binding the piece as you perform the cross cut.

This image shows the correct position of the auxiliary fence/stop block relative to the blade while performing a cross cut.

Proceeding on, the image below shows the results of the test cut. The piece is sitting proud of the edge of the drawer front by a smidgen. To correct this the blade needs to be raised by a corresponding smidgen.

The correct fit after raising the blade is shown below.

Once the correct fit is established, the cross cut is made on each end of both drawer sides with the outside of each drawer side facing up.

All that needs to be done is to perform a dry assembly of the drawer, establish the size of the drawer bottom, cut it and then a dry assembly of the drawer with the bottom in place.

When gluing the drawer together, checking the diagonals match is an easy way to ensure that the box is square. I find the square check for tape measures really convenient for this.

September 13, 2010

Cutting a round log on the bandsaw

I love the smell of cedar in my workshop!

A friend gave me a couple of freshly cut cedar logs recently. The logs were fairly small diameter, about 5″ and the pith was offset quite a bit to one side. I cut the logs into 2′ lengths using my chainsaw, but did not want to split the logs using my chainsaw. I knew I would get cleaner, more accurate cuts with my bandsaw and would waste far less of the wood. I needed a safe way to cut the round logs on the bandsaw.

This is the simple jig I put together. Two pieces of scrap plywood with a couple of supporting triangular brackets.

The log is then screwed to the jig at the front and back of the jig. I made sure that the screws went into waste wood.

Set the bandsaw fence making sure that you will not be cutting through the screws! Because the log is screwed to the jig, it will prevent the log rotating while it is being cut.

Once a flat surface is established, cutting the log into spindle stock is fairly straightforward.

The end results. A bunch of 2″ to 2 1/2″ spindle stock with some beautiful color. Ready for the end grain to be sealed and then stacked and stickered to dry.

September 6, 2010

TV Area Built In

I finished installation of the TV Area Built In that I have been working on. I installed the base cabinets about a week ago and then had to wait for the top shop to install the granite top before I could install the bookcase unit and crown molding. The built in looked very nice and most importantly my customer was happy with my work and the finished product. This is the same customer who I designed and installed a dining room built in for.

Some of my recent posts have been about the work that I did on this built in. You can read them at these links:

September 2, 2010

Bowl depth gauge

Ever made a lampshade out of a bowl? I’ll never admit to it, but I’ve heard of people hollowing right through the bottom of a bowl 😉

I recently turned a bowl and the bottom was a lot thinner than I liked and getting dangerously close to becoming a lampshade. So I decided to make myself a better bowl depth gauge. Something more accurate than my current method of holding my gouge at the center of the bowl, eyeballing along the rim of the bowl and then bringing the gouge up and out of the bowl to eyeball how deep I was with my hollowing. I wanted something that would be accurate, but would still be quick and easy to use.

A visit to the plumbing section of Home Depot and I returned with a couple two foot sections of 3/4″ PVC, two tee sections, a 90 degree elbow and a cap. The wooden morse taper I turned and the rifle laser was purchased off Ebay.

I cut one of the PVC pipes in half and then cut an 8″ section off the other. (The length of the 8″ section was determined by the swing of my lathe, half of 16″. I cut the other pieces to 12″ as with the current tools that I have I’m unlikely to be turning a hollow form any deeper than that.)

Depending on the laser sight you get some adaptions may be needed to one of the PVC tee pieces. In my case the diameter of my laser sight was slightly greater than the internal diameter of the tee piece.

I mounted the tee piece in the pin jaws of my chuck using a 60 degree live center to help mount it true.

Then, with the lathe speed slowed down, I drilled it out with a Forstner bit that matched the diameter of the laser.

A nice snug fit.

I turned a tenon on the wooden morse taper that matched the internal diameter of the PVC pipe and then I pieced all the parts together.

Here is the depth gauge mounted on the lathe. The wooden morse taper is inserted in the tail stock. It is not necessary to jam it into the tail stock.

Side note: With a self ejecting tail stock it is not considered a good idea to use a wooden morse taper. Click here to read a discussion on this subject.

So, throwing caution to the winds, I mount my bowl depth gauge in the tail stock. Once everything is adjusted and the laser is shining on the tip of the cap, a couple of drops of CA glue can be applied to each of the PVC joints. Don’t glue the laser into the tee piece though, at some point you will need to take it out and change the batteries 🙂 The laser sight I got has a switch to turn the laser on and off, a lot more convenient than the lasers you get from stationary stores which require you to constantly depress a button for the laser to be visible.

I’m still trying to get a good shot of the laser on the outside of the bowl. When I do I’ll update this post with a picture of the depth gauge in action.

August 30, 2010

Turning a wooden morse taper

For the technically inclined a Morse Taper #2 has a angle of 1° 25′ 50″, as gleaned from the fountain of knowledge, Wikipedia. For the less technically inclined, myself included, turning a wooden morse taper is a quick and easy project that can be done with some simple measurements.

The first step is to mount a piece of hardwood between centers, or as I have done, in a chuck with a live center at the tailstock for support. True the piece and turn it roughly to size.

Take one of your centers and transfer two marks to the piece indicating the two sides of the taper.

Set a pair of calipers to the diameter of the morse taper upper end, and using a parting tool, part into the piece until the calipers slip over the parting cut. Repeat the procedure for the lower end of the morse taper.

Make a relief cut to the tailstock side that is smaller in diameter than the lower end of the morse taper.

Turn a straight line from the larger diameter to the smaller diameter. You’ll need to sneak up on this slowly and check the line often with a straight edge. I cut up one of those plastic discount coupons to use as a straight edge.

With the piece still held in the chuck, remove the live center from the tailstock and slide the tailstock forward to check the fit of your taper. Rotate the headstock by hand while the piece is in the tailstock to identify the high spots to be turned down. Once the fit is good, round off the end of the piece.

Remove the chuck and insert the new morse taper into the headstock. You can now shape and true up the area that will be used to mount a work piece to. Wooden morse tapers are useful for holding small turnings. They can simply be glued to the morse taper. Bear in mind that there are limitations to the size of a turning as a wooden morse taper is nowhere near as strong as a metal dead center!!

Why did I need to turn a morse taper? Stay tuned 🙂

August 26, 2010

Processing a log for bowl blanks

I often hear turners talk about “free wood”. To my mind there is no such thing as “free wood”. Between the time and mileage spent driving to pick up the logs and the time and energy spent processing the logs into blanks, I often feel it would be easier and cheaper to just buy the bowl blanks!

Cutting your own blanks does have some advantages. The primary advantage is that of re-using or recycling wood that would otherwise be destined for the chipper or the burn pile. There is something very satisfying about holding a finished bowl and knowing that you were involved in the complete process from log to bowl, and you created a functional and beautiful object from some timber that could have just ended up in a landfill somewhere.

However, there is a lot of work involved in processing a log for blanks, and it is frustrating when the end results are just a bunch of checked and cracked blanks. Two very important things that will help you avoid this are:

Process the wood as soon as you can. Ideally you will want to process the log the same day as you get it. When this isn’t possible, try and at least get the chainsaw part of the process done as soon as possible, which will remove the pith and then seal the end grain with Anchorseal.
Remove the pith, remove the pith!!

The picture below shows how I plan on cutting this small camphor log to yield both bowl blanks and some spindle stock. If the log were bigger the spindle stock could be used for hollow forms. This layout is just one possible scenario, the most important thing is that the pith, marked with a red x, is going to be removed and discarded.

Make two cuts down the length of the log, either side of the pith. Don’t cut all the way through with the first cut. In the picture below I have made the first cut and then paused towards the end of the second cut to take the picture. Normally I would have just cut all the way through the log with the second cut.

Complete the first cut.

For the most part this is all that I will do with the chainsaw. I then take the three pieces of wood inside to my band saw. However, some of the cuts that I make with my bandsaw can be made with the chainsaw. I just find the bandsaw more accurate, less wasteful and it’s in the shade 🙂

If the log is fairly straight, I set my fence and then cut off about an inch of the live edge. If the log is not very straight then I will just free hand this cut.

Then using the flat section I just created, I will rotate the log 90 degrees and cut it to the desired thickness. If you do not have the capacity to do this on your bandsaw, then this step can easily be done on the lathe when you first start turning the blank.

I have a set of 1/4″ plywood circular discs in 1″ increments which I use to gauge how large a bowl blank I can get out of the log as well as guide me in the cutting of the blank.

From this section of the log I’ll be able to get two small blanks, one 7″ and one 6″. I draw around the discs with some white chalk and mark the circles to be cut out. I could also just nail the disc to the log and leave it in place while making the cuts.

I would then process the other log half in a similar fashion before moving on to the slab I removed from the center of the log. On this slab I cut off about an inch from both live edges.

Then I would set the fence to the same dimension as the thickness of the slab and cut out as many sets of spindle stock as I can, working towards the center of the slab from either side, being mindful of where the pith is. In the picture below, you can set two pieces of spindle stock either side of the pith section which will be discarded.

Here is the yield from the log. Three bowl blanks, two pieces of spindle stock and a section of questionable orientation that I will probably make a sphere from.

This is the reason why the one log half only yielded one blank and the piece of questionable orientation. The chainsaw cut revealed that I had cut through two nails embedded in the log. This illustrates the importance of inspecting the logs carefully before cutting with either the chainsaw or bandsaw. It also confirms my theory about there being no such thing as “free wood”. My chainsaw blade needs to be resharpened now and if I had not noticed these nails they would have trashed my bandsaw blades. I think I may look into buying a metal detector!

The final step is to coat the blanks with Anchorseal. I cut the entire blank, however many people will just coat the end grain and leave the face grain bare. I’ve found the horizontal section of my new log processing platform to be perfect for this.

August 23, 2010

Log Processing Platform

For the longest of time I’ve been working on the ground when processing my logs with a chainsaw. I had a wooden pallet and I would position the logs on it and then cut them. It worked OK. Often I had trouble securing the logs so they didn’t move while I was cutting them, especially when they were still round. However with the use of wedges and such I normally could work around that and get the job done. And each time the job was done my back was killing me!

So I started looking for ideas as to how I could raise the logs to a more comfortable working high and hold them securely while cutting them. Finally I saw a solution in the June 2010 edition of the American Woodturner, the AAW journal.

The log processing platform was in the “Tips” section of the journal and I’m really pleased with the one I built. It holds the logs secure and steady, has plenty of room for the chainsaw to travel after the cut is complete so the chain doesn’t end up buried in the the dirt, and it raises the logs to a comfortable working height, which my back is really pleased about!

I built mine from pressure treated pine. It took about ten minutes to cut the timber to size, cut some 45 degree angles on the uprights, and then I shot it together using a framing gun and some galvanized nails. The four tall upright pieces are 32″, the two shorter upright pieces are 26″. The gap between the tall pieces is 7″ and the other gap is 4″.

Processing logs with my chainsaw is a far more enjoyable experience. Quicker, safer and less stress on my back. My thanks to the reader who submitted this tip to the AAW Journal.

August 19, 2010

Installing Concealed Hinges

Installing concealed hinges can be a pretty simple process, even using a hand held drill, with the help of a jig. The Rockler Concealed Hinge JIG works really well at positioning the Forstner bit, as well as holding it square to the door frame surface and finally controlling the depth of the hole. Of course, if you have a drill press with a good fence and large enough table then that will work just as well.

The first step is to mark the center line of where the hinge will be positioned. Then position the jig using the alignment arrows and clamp it in place. Note: the clamp is on the underside, or show face of the door. You can’t see it in the following picture and I didn’t take a picture showing it. Sorry, my bad.

Set the stop collar on the bit guide so the bit drills to the correct depth. I like to drill a test hole in a scrap piece of wood and make sure the hole is deep enough to allow the hinge to fit in without bottoming out.

The bit guide is then positioned over the alignment plate. The wide circumference of the bit guide ensures that the bit is held square to the work surface, important when drilling with a large Forstner bit. As the bit guide fits over the alignment plate it also stops the bit from wandering.

After placing the hinge in the hole, check that the back of the hinge is parallel to the frame using a square.

Use a self centering bit to drill pilot holes for the hinge screws.

August 16, 2010

Building a Flat Panel Door

A flat panel door can be defined as a door in which the panel has no bevel or hip raise. It can still be considered a five piece door, as it consists of two stiles, two frames and a panel. The stiles are the vertical members of the frame, while the rails are the horizontal members.

The first step is to mill the wood for the stiles and rails of the doors. I am building three doors for some base cabinets. All three doors are the same size and the cabinets will be painted white. I am using poplar for the frame of the door and 1/4″ plywood for the flat panel. The stiles and rails are 2 1/2″ wide, 3/4″ thick and I cut them an inch or so longer than what I needed. While I was preparing the wood I also took the time to make some scrap pieces the same width and thickness to be used for test cuts. You can also see my set up block in the picture. You can also see my raised panel router bit set. For this project I will only be using the two bits on the left, the monster raised panel bit will stay in the box.

Mount the bit for cutting the profile on one edge of the stile and rails. I use my set up block to adjust the height of the router bit, although I still plan on making some test cuts in scrap wood. The profile in both the stiles and rails will be cut with the face side (the outside of the door) down.

A close up shot of my set up block. I keep this in a drawer right next to my raised panel router bit set.

The fence is then moved so that it is flush with the bearing of the bit.

After routing a profile in a scrap piece of wood, I use the rail section of my set up block to see if the two surfaces meet flush on the top surface. I got lucky this time and the fit was perfect 🙂

I then routed the profile on one edge of all the stiles and rails. Remember the cuts are made with the show side down. For this project it was not that important as the doors will be painted, but if you are not painting the doors you will want to take care to chose the best side of each stile and rail and then to route it with that side down.

I then took the stiles to the table saw and used a cross cut sled cut them to length. To calculate this length I measure the height of the door opening and added 1 /4″. My crosscut sled was not quite wide enough to enable me to use its stop block, so I used a fence clamp and a block of wood as a stop block.

The next step was to calculate the length of the rails. I wanted the door to overlap the door opening by 5/8″ all round. The depth of the groove in the stiles was 3/8″. The width of the stiles was 2 1/2″. So the length of the stiles needed to be:

(Door opening width) + (2 times 5/8″) – (2 times 2 1/2″) + (2 times 3/8″)

To many years in school dealing with the metric system means that I suck at working with fractional inches, so I always reach for my handy ProjectCalc Plus at times like these!

The router bit for routing the sticks in the rails is mounted in the router table and set to height using the set up block. Again the fence is positioned so that it is flush with the bearing.

Remeber those scrap pieces of wood. Route the profile in the end of one of them. When making this cut it is important the the rail be kept flat on the table face down and that it remain at 90 degrees to the fence. It is also important that the cut be backed up to prevent tear out as you are routing end grain. There are a number of commercial rail coping jigs that will allow you to achieve this easily. I don’t have one, although every time I build some doors I promise to buy myself one. So what I normally end up doing is to cut a piece of 3/4″ plywood or mdf, making sure that one corner is a perfect 90 degrees. Then I use that sacrificial piece of plywood to hold the rail square to the fence and to back up the cut.

Satisified that the set up of the router bit was correct, I made the coping cut in all of the rails. Remember to make this cut with the face side of the rail down!!

Calculating the size of the panel is pretty simple. Measure the frame opening, then add for the 3/8″ groove all round and then subtract to allow for expansion. With a solid wood panel you would want to subtract at least 1/8″ all round. With the more stable plywood panel that I’m using I subtracted 1/16″ all round. The groove is 1/4″ wide so the undersize 1/4″ plywood fits pretty loose in the groove. However with a couple of coats of paint it should fit just right.

Test fitting the panel.

I like to paint the panel before gluing the door together. That way if there is any expansion of the frame then there won’t be any unfinished part of the panel exposed. This is probably more important with solid wood panels, but it is a good habit to get into.

When gluing the door together the panel is not glued into the groove. Glue is only applied to the coping cuts on the rails. The glue should be done on a flat surface so that the door will be flat and it should be checked for square. I really find the square check for tape measures useful when checking for square.

In closing, and before you head out to the shop to start making a set of doors, I invite you to review a previous post on router feed direction and bit rotation.