Snare Drum – Bearing Edge, Jigs & Mounting Hardware

While I had cleaned up the parted edge it was not really finished.  I needed to get a flat square surface before I started on the bearing edge detail.  To get that I started by clamping a couple of sheets of 120 grit sandpaper to the extension on my table saw and chalked up the parted edge.

Chalked Edge - Ready to Flatten 

Flipping the chalked the edge over I carefully sanded that surface checking frequently to see when all the chalk had been removed.  When it was gone I knew I had a flat and square surface.

Flattened Edge

To get the double 45 degree bearing edge we had decided on I used a 45 degree carbide chamfer bit in the router table.  From my experience turning the shell I knew that Leopardwood is very hard.  What I did not know was how brittle the wood was and how susceptible to chipping it could be while being routed.   With that in mind I decided to error on the side of caution using climb cutting and taking many passes on the router table to cut the bevel.  

Bearing Edge Detail and Router Setup

The router in my table is a 3½ horsepower model and to get a feel for how the leopardwood would route I started with a cut just over 1/16” deep.  Surprisingly, even with that small a cut I could hear the load it put on the router.  As the depth of the bevel increased the size and amount being cut increased I gradually reduced the cut depth to keep from loading the router too much.  The last cut was just over 1/64”.  Here the top and bottom inside bevel has been cut.  I will wait until after I get the holes for the lugs measured and drilled before I cut the outside bevel for a couple of reasons.  First, I wanted a flat surface for reference when I layout the lug holes.  Second, where the two cuts meet there will be a fairly sharp edge that I do not want to dent or otherwise damage so the later it’s cut the better.  I will probably make that cut the next to last operation.

Inside Finished Bearing Edge & Close-up

Next I needed to build a jig to hold the drum in the drill press so the mounting holes would be on axis to the drum center.  I also wanted a softer surface against the drum so as not to scratch the finish sanding job.  To that end I beveled a couple pieces of extruded Styrofoam to closely match the curve of the drum, mounted them to a piece of MDF and clamped it all to the drill press table.

 

Jig for Drilling Lug Holes

Once I got the new lugs I could measure for the hole size and layout where they will go.  With that done I set the shell in the jig, used a square to align it so the drill hit my mark and is lined up with the shells center line.  Now with everything braced in place and square I clamped a piece of 4” PVC pipe in place.  This will act as a backup so when drilling the holes the drill would not blow out the backside of the shell when it cut through.  If you look at the right image you can see the white of the PVC at the bottom of the hole.

Jig and Close-up of Hole

After getting everything set for the first hole it’s a simple matter of loosening the band clamp, rotating the shell 36 degrees, aligning everything then drilling the hole.  The setup takes way longer than the actual drilling.  Repeat the process 9 more times and Ta-Da it’s done, ready for the lugs to be attached.

Shell with Lug Holes Drilled

At this point I did a test fit with all the lugs, tension rods, heads and hoops installed.  Everything aligned, was plumb, square and fit just perfect.

Test Fit

With that done it’s on to adding the last two pieces of hardware.  The throwout which controls the snare on the bottom head and it’s anchor on the opposite side of the drum.  Since we had not decided their location as to how far up they went on the side of the drum a brief discussion with the client answered the question, 2” from the bottom.  More measuring and 4 holes later they were mounted.

Throwout and Anchor Installed

The next step was to cut the outside part of the double 45 bearing edge.  It is cut the same way as the inside, using the router with a 45 degree bit.  After a couple of passes I marked the flat area on the edge with a red marker shown on the left photo.  With that as a guide I raised the router bit a little at a time until only a trace of the line remained, right photo.  Lastly, a light sanding rounded and blended that flat surface into the two 45 degree angled cuts giving the bearing edge we wanted.

Cutting  Outside of Bearing Edge (L) in Progress, (R) Ready to Blend

Only one bit of woodworking remained and that was the arc for the snare cords.  To make this last jig I took a full size print-out of it, laminated that to a piece of cardboard and cut it to shape.  We had initially set the cut depth at 3/16” as shown here but in a later discussion the client wanted to decrease the depth of the cut from 3/16” to 1/8”.  That was no problem I just adjusted the template I had made down by 1/16” and clamped it in place. 

Snare Cut Template

Using a small drum sander in the Dremel tool I cut the rim to size then did the same on the opposite side.  Some hand sanding to clean up the surface, ease the edges and I was done.

Finished Snare Cut

That only left some final hand sanding and I was ready to apply the finish.

Sanded Shell Ready for Finish

Next Up – Finishing & Another Problem

Snare Drum – Parting Off, Layout & a Problem

Before I parted the drum from the mounting assembly I did one last check on the dimensions because I wanted to make really, really sure I had everything right since once the shell is cut off I cannot make any adjustments.  With everything checking out I started the process of parting off or cutting the drum shell away from the mounting fixture.

This shows the cut about half way through.  The pencil marks at the bottom of the cut gives me a reference mark so I can gauge how fast I am removing material.

Parting Off Operation in Progress

The closer I get to cutting the drum shell free the more paranoid I get.  What I don’t want to happen is to have the shell come lose, hit the lathe, the wall or me and damage the shell or me.  When I got to where I had less than a sixteenth of an inch left I shut the lathe off.  Because the mounting ring is made from construction lumber it is fairly soft and I could hold the parting tool in one hand and turn the shell with the other hand cutting the remainder away.   Here there is a very thin swiss-cheese looking band of material left holding the shell on, in fact when I looked inside I could see the light shining through it.

Shell Just Before Removing from Mounting Fixture

At this point a little tap on the shell caused it to release.  As you can see that there just was not much holding it on.  There is also some little bits of the base still on the shell that I will need to remove, but at this point everything looks good.  The real test came when I measured the diameter.  The result is good news, the thickened edge was within a few thousands of and inch and the overall diameter is right on.  All the measuring and checking paid off, what a relief! 

Shell Removed from Mounting Fixture

My next step was to clean up the parted edge removing the remaining bits of the mounting ring.  With that done I could do a test fit with the top and bottom drum heads and hoops held in place with 3 of the mounting lugs.  At this point it looks almost like a drum.   One thing I noticed was how light the shell felt, when I set it on the kitchen scale I was surprised in that it only weighed just under 3 pounds.

Test Fit of  Hardware

Lug Test Fit into Scrap

There are 10 lugs that hold the top and bottom hoops in place.  My first step was to do a test fit on a scrap to verify the center to center mounting distance of the holes and their size.   With that done I could lay out the hole locations on the drum shell.

To lay out where the lugs go I needed to make a template.  The starting piece was the top layer of MDF from the mounting fixture.  Since the mounting fixture was held together with screws I could easily take it apart.   The 10 lugs get evenly spaced out at 36 degrees between them.  To do the layout I drew a circle the diameter of the drum, used an Incra protractor to get the angles then measured the distance between the points where the lines intersected the circle as a check.

 

Completed Lug Spacing Jig

With the template made I could mark on the drum the lug spacing.  From there I added blue painters tape to use as a marking surface and extended the vertical center lines of the lugs onto it.

 

Center Lines of Lugs on Blue Painters Tape

Because I had only a few thousands of an inch tolerance in the spacing of the lug hole locations I used a marking gauge with a knife rather than a pencil.  The knife cuts a line far finer than any pencil.  Also, the cut in the tape will act as a guide when I use a center punch to create a dimple for the drill bit.

Marking Gauge

With the gauge set I marked the center line of each hole location.  Both the top and bottom holes were marked off the same reference edge for consistency. 

Marking Gauge Cut 

Lug Mounting Problem

As I was marking the next to last hole it dawned on me that the holes seemed to be pretty close to the bottom edge of thickened rim.  With that in mind I was afraid that the hole might come through the transition area between the thickened rim and the thinner central part of the drum shell.  If so, this would cause a problem in that the screws holding the lugs on had washers over ½” diameter and they would not lay flat if one edge was in the transition area.  A little measuring confirmed the problem.  The bad news was that I had the hardware in hand and the holes all marked.  The good news was that I had not drilled any holes in the drum shell.

I sent the client a drawing illustrating the problem and in a video conference we came up with several ideas, the best two were:

1. Get lugs with a shorter center to center attachment distance.  This will move the screws and washers more toward the center and out of conflict with the transition.
2. Get lugs with a single center mounting point.  This moves the screws and washers to the center of the shell completely out of the way.

We decided that Option 1, lugs with a shorter center to center attachment distance would be the first choice and center point lugs would be the second choice.  A day later I got a note from the client saying that after reviewing the available options he had ordered single point lugs.  With that problem out of the way and while waiting for the replacement hardware to arrive I moved on to milling the bearing edge.

Next Up – Bearing Edge, Jigs & Mounting Hardware

Snare Drum – Final Glue-up & Finish Turning

I had not glued up the 4th ring yet and when I was ready to do so I asked my wife to take some photos of the process.  Here are a series of shots that hit the major points.  Seven minutes for stacking the pieces for gluing, applying the glue, setting the pieces in the ring, clamping and “adjusting” them with a hammer for fit and finally about 3 minutes for some cleanup.

While waiting for the glue to cure I started to turn the interior to it’s finished size.  I was already within 1/16” so there was not that much material to remove but it did take some time to gradually pare down the surface and get it flat as I really did not want to overshoot the mark.  This is a progress photo showing I still had a few hills and valleys to flatten.  I will say that cutting a flat surface freehand to an exact dimension is a bit nerve-wracking.

Just a Little Flattening to do

Once I had a good flat surface the right size I did some finish sanding and was ready for the fourth and final ring to be glued on.  Here the lathe is turning very slow, about 50 RPM's.  That in combination with the the drill and sanding pad gives a good finished surface.

The next day I went through the taping, flattening, gluing and clamping process for the last time.

This last ring is thicker than the previous two since it will have a thickened edge just like the first one I glued on.  Now mounted back on the lathe I could start the final turning steps.  I am sure glad this is the last ring, the assembly is getting heavier and more awkward to put on and take off the lathe each time I add a ring.  I think dropping it now would not make me happy.

Inside and Outside Views of Final Ring Ready to Turn

As before after knocking off the outside corners and getting it just round I started working on the inside.  You would not believe the contortions I had to get into to see what I was doing to turn the step-down between thick edge and the thinner shell.

The interior diameter goal is 12 ⅞”, ± twenty thousandths of an inch with a smooth straight surface square with the rim and parallel to the central axis.  At least for me that’s not so easy when working freehand on the inside of a cylinder.  I think that’s one reason it took so long to get the inside just right.  Also, if I overshoot and cut too deep that would be a bad thing.  Anyway, here I am just a smidge from getting to where I wanted.

Here the inside turning and sanding is done.  I am now ready to start working the outside down to the final diameter.

Interior with Turning and Sanding Finished

Line Showing Outside Face Location

Before I started turning I measured and marked a line on the rim close to where I needed to cut down to.

I am going to turn down to the final diameter working from the outside end toward the headstock.  My first band is about ¼ the length.  The reason I did not go all the way at once is I want to keep as much mass on the blank as I can for stability.  I ran into some flexing and vibration on the third ring and did not want that to happen here.  When done with the first band this is what it looks like.  The outside edge is ½” thick and after the inside stepdown the body of the shell is ¼” thick. 

First Quarter of Outside at Finish Size

BIG Callipers

Measuring the diameter is easy on the exposed edge but not so easy farther down and I needed to keep a constant diameter along the entire length.  None of my calipers could measure a 14 ⅜” diameter cylinder so I spent some time making an oversized set that Rube Goldberg would have been proud of.

The next band was about a third of the drum.  Having gotten experience with the first band the second one went a little faster with the chips flying.  At least until I got to that last little bit where I snuck up on the finished diameter.  Turn some, measure, turn some more, measure and repeat.  My concern regarding flexing and vibration was well founded in that as I got close to the final diameter I began to experience some vibration that produced a ridged surface.  Not what I wanted.  Honing the cutting tool and adjusting the rotating speed of the piece eliminated the vibration and I was able to continue.

Turning Away

Hole to Allow Measuring Drum Wall Thickness

When I got to the very end of the last band where the drum is joined to the sacrificial ring I wanted to check the thickness of the rim.  To do this I drilled a small hole in the sacrificial ring right next to the drum edge.  With that I could use the dial caliper to measure the rim thickness.  When I did the measurement, good news, the thickness was within a few thousands of what I wanted.  A great relief after working blind.

After some sanding the lathe work on the drum shell is done with all of the dimensions where they need to be.

Stepping back and taking a look at the shell and the lathe I realize what a bunch of material I had removed to get to this point.  By the time I got it all cleaned up it pretty well filled a 20 gallon trash bag.  I could have made the segments a little thinner and would have had less material to remove but I decided not to cut it too close as I was not sure what problems might crop up and wanted to have some wiggle room.  

Last was to take the assembly off the lathe and do a trial fit for with the drum head and hoop.  Everything fit to a tee, can you see the big smile on my face?

Trial Fit of Hoop & Drum Head

Next Up – Parting Off, Layout & a Problem

Snare Drum – More Discussion on the Bearing Edge & Adding Rings

The detail that has been in a constant state of flux is the profile that will be used for the bearing edge.  We have talked about at least half a dozen various designs, I have created several drawings and three different physical mockups.  Good news is that we have settled on the double 45 degree profile.  However, I was a little concerned with the size of the flat on the mockup being too small but before I could email the client he sent me a note questioning its size.  Back to the drawing board to create a revised drawing that increased the flat from less than ¼” to a full ¾” but this was too much. 

After making a couple of mockups, one at 5/8” and one at 9/16” we agreed that 9/16” looked like the best fit.

Left 5/8" and Right 9/16" Bearing Edge Mockups

With that decided (for now) I marked up the roughed out rim ring so I could start working on the finished turning.  The two lines on the left face represent the completed thickness of the bearing edge and the single line on the right is where I will start the transition from the thickened bearing edge down to the ¼” thick body.

Layout Lines for Initial Turning

Here I have turned the interior thickened rim down to it’s final dimension and the thinner body nearly down to it's finished dimension.  I am leaving the thin section a little thick for now to allow for any glue runs from the next ring and to provide material for a smooth transition between rings.

Turning in Progress

With the rough turning done I taped the inside edge to catch any glue runs when I put the second ring on.  I am not planning on any major runs but it’s better to be safe than sorry.

Taped Blank Ready for Second Ring

The preparation for gluing the second ring on is the same as the first, running it through the thickness sander to flatten and make the top and bottom surfaces parallel to each other.   The only other thing was to add some registration lines to align the joints in the second ring so they are centered on the segment block below.

From there it was just getting everything ready to glue up and doing a dry run to make sure it was going to go together without problems.

Setup for Gluing

After the dry run it’s a simple matter of gluing and clamping everything together.  Have I mentioned that you can never have too many clamps?

Letting the clamped blank cure overnight I then took off all the clamps and mounted the blank back on the lathe.  Although there were no major glue runs the tape was still a good idea because of a number of small squeeze out blobs.

Second Ring Mounted & Ready for Turning

After turning the outside smooth I started on the inside.  This photo is when I have almost completely got the interior rough turned to a circle.  There is just a small ridge left to remove.  When that is done I will turn the inside very close to the required diameter which will blend the two rings so the transition  between them is seamless.

In the photo below the inside turning is done on the first and second layer, the piece has been removed from the lathe and it is ready for the 3rd layer to be glued on.  You can see the interior smooth transition between the first and second layers.

Ready for Third Ring

The process is the same for the third ring as the second one so there is no need to go into any detail here.  It’s just a little time consuming as I only have enough hose clamps to put one ring together per day.  Only exception is as the rings stack up I have to go to taller clamps.

 Here is piece with third ring glued on, mounted on the lathe and ready to turn.

I did run into one problem turning this layer.  The outside turned down fine but while I was working on the inside I began to feel some vibration while turning at the outer edge.  The vibration did create some ridges but not enough to cause a major problem.  In an effort to cure I stopped, sharpened the tool, adjusted the lathe RPM to a different speed and that solved the problem.   I hope the vibration does not increase when I add the fourth and final layer.  However, experience is that the farther you get away from the headstock with unsupported material the more likely the vibration problem rears it's ugly head.   The good news is the 4th layer has a thickened rim so the additional mass may help out.  It will be interesting to see what happens.

Three Layers Done and Ready to Add the Fourth

Next Up – Final Glue-up & Finish Turning