Wednesday, July 30, 2008

Making Rails

OK. We've got the major joinery cut on all the posts. We're not done yet with the posts, but at this point, I began working on the rails & central stile of the very front, since I had all of the wood for these parts sitting around after milling them up before we went to Hershey.

I started by cutting these parts to width & length from the stock I had prepared. I cut these to the dimensions from my drawing, since their lengths would determine the final dimensions of the pulpit from font to back. I will use relative dimensioning when I cut the shelf supports & shelves, as well as everything else from that point on.

One interesting thing I did was make a wooden spacer exactly 1" long. The center rails are exactly 1" shorter than the top & bottom rails. By inserting the spacer between the stop on my Osbourne EB-3 when I went to cut the center rails, I got them exactly 1" shorter without having to move the stop block. This saved time & prevented mistakes by readjusting the stop block (I don't have a tape measure on my EB-3).

When I got to the center stile on the front of the center box, a soft, still voice told me to cut it long. When I heard it, I reasoned it was a good idea, since the actual length of this piece would depend up on the depths of the grooves I had yet to cut in the top & bottom rails, and on the distance between the mortises in the front two posts. I needed to cut it to 40 1/2" according to the drawing, so I ended up cutting it to 41".

After cutting these parts to final width & length, I routed grooves in them by mounting the same spiral up-cut bit in my router table. I set the depth to 1/2" & placed a post on the table with the bit in the groove. I then adjusted the router table fence so it was against the adjacent face of the post. And I started running rails. Everything ran fine here, no mistakes.

Next, I began cutting tenons on the ends. The top & bottom rails all have 1" long tenons. The center rails, as well as the center stile on the front, all have 1/2" tenons. I decided to cut the 1" long tenons first.

I attached a stop block to my fence & set it so I would cut a shoulder 1" from the end of stick. I set the height of the blade to 1/4" and I started cutting shoulders. All went well. I then reset the fence 1/2" closer to the blade & made all the shoulder cuts on the center rails & stile stock. Again, all went well.

Time to make the cheek cuts. I grabbed my new tenoning jig that I got for Father's Day (gloat!) and set it up. Again, I started with the 1" long tenons. Everything was going well & I was getting great tenons that were a little too fat to fit in the mortises, which is what I wanted. Some where along the way, I ended up grabbing the stick for the center stile & I mounted it in the tenoning jig & ran it through. Doooh!! The shoulder on one side of one tenon now has a kerf running 1/2" up! Some how, this didn't upset me so much as cutting through the corner on the post had. I remained pretty calm & figured that since the kerf would be hidden when everything was assembled, I'd just fill it in with one of the cheek cutoffs. So I finished cutting the 1" tenons & then did all the 1/2" tenons.

After I'd finished making all of the cheek cuts, I began tweaking & adjusting the tenons so they'd fit into the mortises. I did this by first making a few passes on both faces with my shoulder plane until I could slip the tenon into the groove. I then eyeballed the location of the haunch & marked it on the tenon. Next I cut the haunch using my pull saw. I put each frame together as I went from rail to rail, sort of as a dry fit.

It was while I was putting the center frame together that I realized I had cut the center stile long on the off chance it was too short. This became obvious when I couldn't get the top rail square to the post I had inserted it into after I slid the center stile into its grooves. So I put the frame together without the center rails & stile & measured. And here's the second reason I think God Himself is working on this pulpit with me: I had to remove exactly 1/2" from the stile to get it to the right length. After cutting a new tenon, that would totally remove the mistake from the stile! There's nothing to patch or hide!

So I recut the tenon & finished the dry fit. Here are some pictures of the frames dry fitted together. The left wing:

The right wing:

And the center frame:

I did notice in this dry fit that the grooves I'd cut in the posts were about 1/32" too far from the adjacent face of the posts, since there was about that much of a ledge left visible after I installed the rails. I guess I didn't have the edge guide set to the right distance when I cut the mortises & grooves. Next time, I'll have to remember to double check that dimension with a shallow test cut before I go gang busters on it.

Next time: I Finish Making the Posts

Saturday, July 26, 2008

We're Making Progress

When last we met, I had finished milling the stock for the 12 corner posts to thickness and had cut them to width. And we were leaving for Hershey, PA. That's mostly correct, as I finished these operations before July 4, and we actually left on the following Monday. I did get a little bit more done than that before leaving for Hershey.

I had decided that a 1/4" mortise looked minuscule on a 2" x 2" post, and I was worried that this joint might end up not being strong enough. I expect all kinds of people to be leaning on top of this pulpit as they deliver their sermons, and I know a 2" x 2" post will handle lots of weight, but my confidence in a 1/4" tenon under a load like that isn't there. So I decided to mill the rail & center stile stock to 7/8" thick & make the tenons 3/8" thick. But I could only do this if the stock for these elements was actually flat at 7/8" thick.

I had time to mill the stock for the rails & the center stile to thickness before we left, so I went ahead & did it. This changed the ordering of the steps in my "How Am I Going to Build a Pulpit?" post, but better safe than sorry. The stock was nice & straight before I got to 7/8", but not before it was less than 1" thick. So 7/8" is the thickest I could get. This is fine & I think everything will work out OK. Frankly, 1/4" mortise & tenons are probably fine, but I feel better at this stage.

When we got back from Hershey, I started to cut the joinery I had so carefully layed out on the posts. The first three kinds of cuts I needed to make were done with my DW 621 plunge router, the router's edge guide, and a 3/8" CMT solid carbide spiral up-cut router bit. I had to go out & buy this bit as I didn't have one in this size. And it turns out that it's a metric 3/8". That is, it's some metric size that is almost but not quite actually 3/8" in diameter. I didn't realize it wasn't a true 3/8" until much later.

I cut the mortises first. I set the router so it would plunge to 1 1/16", the depth of my mortises. The tenons are supposed to be 1" long & I wanted to leave a little room for the glue to go. I cut the mortises using a technique I had read about & it worked well. Instead of making multiple passes at progressively deeper settings, I essentially drilled a number of overlapping holes to full depth along the length of the mortise. When I had enough holes drilled, I then passed the router along the length of the mortise at full depth. This cleaned up the little triangles of stock left along the walls of the mortise.

The results were nice, clean mortises at full depth. Unfortunately, the mortises are not all uniformly long. I had my shop vac hooked up to the router, sucking up the chips as they were made. This meant that I had to look through a clear plastic ring that the bit passes through, as well as through the clear base. And the lighting wasn't that great -- the router body blocked a lot of light. The end result was I really couldn't see my layout lines very clearly, and some mortises are shorter than others. I need to rig up some kind of light on my router, or get a goose neck lamp I can use to illuminate the work. In any event, I was happy with the mortises. I would just have to cut the haunches in each tenon by hand & custom for the matching mortise. No big deal.

Next, I had to cut grooves along the length of the posts on the faces where the mortises were cut. I used the same router, bit, and edge guide, changing only the maximum depth of cut. In this case, the depth of cut was set to 1/2". I cut the grooves in two passes, one at 1/4" and the other at 1/2". This was working fine, until I was cutting the first pass on the last groove.

I still had the shop vac attached to the router & it was getting all the chips & dust, but I noticed that sometimes it wouldn't get everything. I realized that the filter in the shop vac was probably clogging, but I didn't want to stop just then to empty the vac & clean the filter. It was the last groove, after all. So what I did was to reverse the direction in which I was pushing the router so the vacuum could get another shot at picking up the chips. I had been doing this on the last couple of grooves & nothing had gone wrong.

In this case, it was a bad move. I think the bit must of started climb cutting & I didn't have a firm enough grip on the router. Next thing I know, the bit had cut through the 1/4" shoulder in the middle of the front face of the post. The post was now useless in that position, and I didn't have the stock to make a new post. The router got shut off, I stripped off my safety goggles, ear muffs, and dust mask, and went away to cool off & ponder what to do.

After thinking about it for an hour or two, I figured out what to do. The post that got damaged was the right front post on the right wing. Picture a square; the post was supposed to sit in the north-east corner on the right hand side of the finished pulpit. I decided to swap that post with the one for the left rear corner, or the south-west corner of the square. In that position, the damaged corner would get cut off in order to form a rabbet, so the damage would disappear. There was only one problem: I had cut mortises & a groove on the face that would face the user once the post was in its new position. I would have to fill in these no longer usable joinery cuts.

I still had some 1/2" thick cut-offs left over from forming these posts. I picked one & planed it to about 3/8" thick in my thickness planer. I then cut it to length & glued it into the groove. After the glue dried, I ripped off the extra material, leaving it a little proud of the surface. I then ran that face up through the planer and got it flush with the face of the post. The resulting patch is almost impossible to detect on the post face. This is one of the reasons why I say that God Himself is helping me with this project.

Here is a picture of the patch. You can see where the patch is on the top face of the post, and you can see how difficult it will be to locate the patch on the face after staining & maybe a little more stainable wood filler.

I had to go back & lay out & cut new mortises in the new post for the right front corner, and then cut the grooves. I also cleaned out the shop vac. There were no mistakes on this stick.

Next time: Making rails

Tuesday, July 15, 2008

Work Has Begun!

I began working on the pulpit about the time of my last post, almost 3 weeks ago from the time of this writing. Actually, right after I finished work on the corner cabinet, I had to rebuild my clamp rack, which literally fell apart & off the wall of my shop while I was applying finish to the corner cabinet. The issue with the clamp rack had to do with the fact that I used solid wood for the stiles & had drilled holes in the end grain for home made pivot hinges. The wood split out under the load. Not that I own all that many clamps . . .

At any rate, after remaking the rack, I got started milling up the lumber for the corner posts. There were three 8/4 boards about 2 1/8" thick, give or take, that I needed to be exactly 2" thick after milling, but I didn't have a lot of hope that they would turn out to be that thick. Also, the boards were about 10 1/4" wide, and my jointer is only 6" wide.

The grain in these boards was amazingly straight. There was a little bit of cathedral grain in the middle of the boards, and they all looked like they came from the same board. I had more than enough lumber in these three boards to make the twelve posts I needed, so I just went ahead & ripped the three of them in half.

After that, it was time to face joint the boards, my first time doing this for real on my new jointer. This went very well & a lot faster than I thought it was going to go. Next I edge jointed the boards & that also went a lot faster than I thought it was going to.

When I was finished planing & flattening, the boards turned out to be about 0.005 or 0.010" more than 1 7/8" thick. This was almost a full 1/8" less than I needed. However, the eye really wouldn't pick up the difference in thickness, so I wasn't concerned about it.

After getting the stock milled, I then ripped the boards into posts. I did this by ripping a post about 2 1/32" wide. I then planed the saw marks off of the cut-off before ripping the second post from that piece. Once all of the posts were cut, I then planed the saw marks off of the cut faces of the posts.

Once the posts were cut, I left them alone for a few days, leaning against a wall in my garage. I'm happy to report that these posts have moved less than 1/32" from straight since then. With the changes in humidity we have here in the summer, some movement is inevitable.

I then began laying out all of the joinery I needed to cut. This was complicated by the fact that no two posts were identical, and they weren't symmetrical, so each post's orientation relative to the others mattered. I marked up one post, and then realized that I got one face wrong. I ended up sanding the marks off & trying again. I eventually got the layout correct, but it took a few days working for an hour or two after dinner.

At this point, my two week summer vacation began. I spent part of the 4th of July milling the lumber for the rails & center stile. Then we had to pack for our trip to Hershey, PA.

Next: Cutting joinery