Crawls Backward (When Alarmed)

IconProjects, musings about guitar builds, guitar repairs, vintage tube amplifiers, old radios, travel, home renovation, and other stuff.

CJ Guitar Tooling Bridge on Danelectro DC-2

You may recall that I put a fabulous CJ Guitar Tooling bridge on the Cancer Killer guitar I put together for my friend (and cancer survivor!).

And then I did some crazy mods to my own Danelectro DC-2. At the time I worked on mine, production of the CJ bridges was in a hiatus, so I settled for a stock 6-saddle bridge. Now CJ is back making bridges and I procured one! Which is a great thing, because I couldn't stand the Danelectro bridge. Too cheaply made, flexes under string tension, too hard to intonate, hard to adjust for string height, just bad.

But I'm going to fix that with my new CJ bridge.

Here's the last time you'll see that awful Danelectro bridge on my guitar.

Good riddance, I say.

You'll notice I went with brass saddles on the bridge - you can get those, or cold-rolled steel, or even rosewood when you order one.

The bridge plate now has five mounting screw holes instead of the stock three. Which means I'll be drilling two new mounting holes in the guitar.

Here I am drilling one of the new holes. You may notice that the hole I'm drilling is a bit large (bit? haha) for a simple wood screw you'd normally use on a Dano bridge.

That's because, in a fit of inspiration lunacy, I decided to use threaded inserts to mount the new bridge.

I figured it might give some added sustain.  And it definitely will be a very solid mount.

If you look closely at the hole in the center of the picture on the left, you may notice that you can see right through it to the inside of the control cavity.

That's because the hole is at the edge of the guitar's center block, and there's nothing there to drive a screw or an insert into.

(Note the test fit of an insert on the left).

What to do?

Easy fix. I glued two dowels into the new holes that I'll drive the inserts into.

Here I'm cutting the dowels flush with the top of the guitar.

One of the inserts was tending to rotate instead of staying put when driving a screw into it, so I used JB Weld epoxy on all of the insert external threads to ensure they'd be solid.

On our way to a super-solid mounting for the bridge plate. I'm using stainless steel screws to tighten it down.

The plate is thicker and much more solid than the Danelectro plate - huge improvement.

Plus it looks a whole lot better.

With the plate installed, we can now put the saddles on. The mounting is a variation on the classic Telecaster screw-and-spring arrangement.

The saddles are angled for improved intonation. And they come with a set of longer and shorter height screws so you can use whatever works best (I used the shorter screws).

CJ sells Telecaster bridges too.

I put the saddles up fairly high so I can just adjust them down when I do the final setup.

And here it is after setup. Looks great and sounds terrific. The intonation is on the money.

I had shimmed the neck on this guitar for the old Danelectro bridge, and I wound up making a new shim since this bridge plate is thicker and I needed more height. My new shim is about 0.70 inches at the body end - the old one was about 0.40.

Here it is from another angle. The bridge is a no-brainer and a steal for the money. You can get one here.


DIY Custom Wood Chisel Honing Sharpening Guides

I don't know about you, but I've had a heck of a time using those chisel honing guides you can buy from woodworking supply places. The problem for me is that you have to do some precise measuring to get the angle right, and then the thing wants to wobble and tip when you're sharpening the chisel. Not to mention that the fact that they're 'universal' means they have to be adjusted for the specific width of each chisel, and they won't stay solidly locked in place.

At least that's my experience.

So I was watching a Dan Erlewine video recently and he mentioned these custom shop-made honing guides for holding chisels for sharpening. "Ah ha!" I said to myself, "THAT is exactly what I need!"

Since I've discovered that I really like making custom pieces and jigs like this, I took a stab at it.

More experienced woodworkers will read this and say "well, duh." It's not a new idea.

I cut up some pine, putting a 30° angle on some small blocks on the bandsaw. I also cut up some small rectangular pieces to serve as guides. Stay tuned - this isn't rocket surgery so the dimensions aren't too critical.

The bevels on my chisels are (obviously) 30°, but you can cut he angle to whatever you need. And read on to see how I made some with a shallower angle.

Here's what I did to make the guides. Really easy.

Put a block in the vise, and positioned two of the guides around the specific chisel. This one is a 6mm chisel, so the guides will be spaced exactly for that width.

If I was a real craftsman, I'd probably have used a hardwood for these, but this was a down-and-dirty proof of concept version. Pine is easy to work with, and it's what I had at hand. It's a jig, not a piece of furniture.

Then glue and clamp down the guide blocks.

At this point, you'll want to slide the chisel back in before the glue dries to ensure the guide spacing is correct.

Before you know it, you'll have a whole selection of honing guides sized for each of your chisels. I have metric and Imperial-sized chisels, so I made a guide for each one.

I applied some Tru-Oil as a finish for these. One thing about the pine, though is that it really sucks up the Tru-Oil - a poly finish is probably better. (And this is about the only thing I'd use the dreaded poly on).

Here are the honing guides after 5 or 6 coats of finish.

Note that I labelled them for each size chisel.

And also note that on the 26mm guide, I had to put a second block on the top - this supports the handle of that chisel since it's longer than the others.

Conversely, I cut away part of the block on the 6 and 12mm guides so it wouldn't interfere with the handle and throw the angle off. In other words, the handle sits clear of the angle on the top of the block.

This is the 26mm guide and chisel in honing position on my Japanese water stone. You can see how that top block supports the handle.

The angle is perfect, and the chisel fits tightly into the guide. Since the bottom of the guide is square, it doesn't want to tip over like those guides with a wheel do.

Oh yeah!

Hone that puppy until it's super sharp!

I found, naturally, that the water and the slurry make a bit of a mess on the bottom of the guides. I'll probably refinish the bottoms with poly so the mixture can't get absorbed into the wood as easily.

Our newly sharpened Two Cherries 26mm chisel.

I finished it with a small (about 1 degree) micro bevel - the bevel isn't perfect because I had originally done it on my store-bought guide - it's not perfectly straight.

And I put a final edge on it with a strop and fine compound. Now I can shave with it.

After I made all of the guides, I discovered that my two smallest chisels - 2 and 4mm - have 10° bevels.

So I measured and marked that angle on the two guides, and cut along that line on the bandsaw.

You can see where there was some tear-out at the ends, but they're still perfectly functional.


SAAB c900 Front Motor/Engine Mount Replacement, Pt 2

You may recall from Pt 1 of this project that there was quite a lot of grease and general engine droppings on the skid plate.

While I had the plate off the car, I took the opportunity to get that off.

I used PB Blaster degreaser which works quite well, and has a nice citrus aroma to boot.

In the interest of saving the planet, I scraped the gunk into a heavy plastic garbage bag. At least it won't wind up in the groundwater or the sewer.

How about that? Super clean.

The other side, the business side that takes the scrapes, has a bit of rust where it's been scraped over the years. A longer-term project on my list now is to clean the rust off and paint that side with galvanizing compound.

And with the fan out of the way, I was able to clean up the front bulkhead as well.

This might be a little crazy.

I noticed that the rubber hoses that connect to the main intercooler pipe have the SAAB logo and part number as a raised molding.

Nothing like some brand identification with white acrylic paint. I used the white paint first - it looked a bit bright, so I went over it with a light grey. Came out well.

Now we slide the new engine mount under the gearbox bracket and line it up.

Note the center bolt is aligned in the middle hole of the bracket.

Start the center nut onto the mount.

Since the engine is still jacked up at this point, the nut can't be fully tightened.

I also found that the 2 bolts on the sides which hold the top bracket on don't quite line up at this point.

Now we can start to let the engine down with the jack, making sure the 2 bracket holes line up.

With the engine lowered, the center nut can be tightened, and the limiting bracket put in place. Then reinstall and tighten the 2 bolts, with their spacers.

Fit and reattach the intercooler pipe and rubber bellows fittings.

Note that I made sure the newly painted SAAB logos are visible!

Here's the other side in place and the clamps tightened.

I need to work on cleaning up this side of the engine compartment too.

All done!

I also polished the aluminum intercooler pipe as well as the hose clamps.

The new mount makes a huge improvement. There is now very little vibration of the gear lever at idle, and it doesn't 'flex' under acceleration as it did before. And the clutch seems smoother at the engagement point as well.

Now that I've done one of the mounts, I'm feeling bold. I will tackle the other 2 when I can. I know the passenger side is very straighforward, while the left side is notoriously difficult.


SAAB c900 Front Motor/Engine Mount Replacement, Pt 1

I mentioned in the last post that I had a list of things to do on Gröna (aka Greeny). This is another item.

The car has that (typical?) c900 movement in the shifter - i.e. a fair amount of vibration at idle and backwards flex/movement under acceleration. So as a first attempt to cure it, I'm going to replace the front - gearbox - engine mount.

To digress a bit on nomenclature: you'll hear people say "motor" instead of "engine." A "motor" is an electrical device. Unless you have a hybrid or an electric car, you don't have a 'motor' under your hood. You have an engine. I'm not ranting here, just being more precise.

Also, I tend to say 'gearbox' because it's a pretty accurate description of what is also called a transmission. Although in the case of a SAAB c900 (and a lot of front-wheel drive cars), it's a transaxle, since the gearb... transmission and the final drive are in the same housing.

First thing is to remove the skid plate from under the gearbox. The front bolts are 12mm, the rear nuts are 13mm.

The plate removed.

Twenty-five years of grime on the engine side of it - I'm going to clean it off later.

Also note the grommet/bushing that fell down on it. I wonder how long that's been there?

I'll need to remove the intercooler pipe and the rubber bellows on the ends of it.

The mount is under there, just can't see it very well yet.

Removed the bracket holding the boost control valve and the connector that runs from the Trionic harness to the valve. You can see the screw that held the bracket in on the radiator rail.

I really like those slide/clip connectors SAAB used. Simple and effective design.

The right-hand side fan will need to be removed to get at the mount.

We use a T20 Torx driver to get the two mounting screws off.

After the fasteners are removed, the fan can be lifted up out of the way without disconnecting its wiring.

Now we undo the clamps that hold the intercooler pipe bellows on. Two clamps on each end.

This is the compressor end - the compressed charge goes from here to the intercooler, then out of the intercooler to the intake.

Here's the pipe removed from the car.

I'll clean it up and polish it a bit while it's off.

Now the mount is visible.

There's a limiter bracket (arrow) that has to be removed first.

Note the open compressor outlet. I'll put something in there momentarily.

A better view of the mount. Easy to access now that the pipe is removed. The bolts holding the limiter bracket need to come off now.

Removing the 13mm bolt on the left side of the bracket.

These bolts should be easy to remove - they don't have a lot of torque on them.

And remove the right side bolt. I just put the ratchet under the radiator hose to get at the bolt.

I've read some comments on the Interwebs that indicate both fans and the radiator need to be removed - this isn't the case.

Note that I stuffed a clean rag into the compressor outlet. Don't want to get dirt or even worse - a fastener dropped down there!

I shudder at the thought.

This is one of the bracket bolts - along with its washer and spacer. Keep these in a safe place so they can go back in just as they came out.

And here's the bracket itself.

When the mount flexes upward, as it would under hard acceleration, the it contacts the bracket which limits its movement.

There is a known 'mod' to the bracket involving putting a piece of radiator or AC hose under the top of the bracket to limit motion even more.

I had a piece of hose cut and flattened, but it was too thick - it would contact the top of the mount, so I decided against putting it in.

With the bracket removed, the rubber bump stop over the mount's center bolt is visible.

The bump stop just comes right out.

It's even shaped in such a way as to only fit one way. Those clever SAAB engineers!

And now we can see the main nut that goes on the mount's center bolt. It's bolted to the gearbox bracket.

Note the height of the bolt in this picture in relation to the bracket.

There is a lot of torque on the nut.

I soaked it with PB Blaster penetrating oil, and tried a breaker bar, but couldn't budge it, so I used my trusty Ridgid cordless impact wrench, armed with a 6 inch extension and a 19mm socket.

Five seconds later the nut was loose.

The gearbox bracket needs to be raised up so the mount can slide out from under it.

So I put a block of wood under the gearbox and jacked the front of the engine up with a floor jack.

Jack it up until the bolt clears the gearbox mount.

I had read about this online and had some trepidation about doing it, but there is enough flex in the other 2 mounts that this works fine.

Note that the bolt is now clear - compare this shot with the earlier one I referenced.

I'd guess I raised the engine up maybe 30-35mm, or about 1.75 inches or so.

The finagle the engine mount out.

In practice, I raised the engine a bit, tried the bracket, raised it another bit, etc., until the mount was clear.

You can see it lying at the bottom near the electrical connector.


Here we have the old mount on the left and the new replacement on the right. Yes, it's shot. Look at how badly the rubber is torn.

You'll also note the washer on the workbench - we need to make sure that's in place on the new mount when it gets installed. That will happen in the next post.