Author Topic: Banjo Build  (Read 110056 times)

Offline S. Heslop

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Re: Banjo Build
« Reply #75 on: May 21, 2015, 02:45:25 PM »


Amazing what a bit of sanding can do. It's to size now with about .6mm taper end to end, and that's good enough for me. Those visible gaps are filled with glue unfortunately, so I don't think I can fill them. But they'll probably be alot less noticeable once all the hardware is attached. I could also place the worst ones where the neck joins.


Started turning the inside, but I didn't feel wholly comfortable doing this. Had a couple of minor gouges before deciding that I was risking making more problems for myself (if not my safety). I then fiddled with router bits for a while, replacing the bearing on one with a bigger bearing. Although the bearing I replaced it with was too big, and I figured it'd probably make more sense to just turn a sort of washer to fit over the existing bearings.

I need to think a bit about what i'm going to do next though. Fancy banjos have tone rings installed, which come in all kinds of ridiculous styles, the simplest being a bit of brass wire or rectangular section set into the top. I think the idea with the tone ring is to have the skin resting on a hard surface so it absorbs less energy. The idea with the apple wood surface is that it's a fairly hard wood and might work by itself, but i'd want to shape it into an inward taper.

If I do go for bare wood I should be able to shape it with a selection of router bits rather than on the lathe. Although i've noticed that the apple wood is awkward to cut so I'll have to test a spare bit (hope i've got a spare bit!) before I risk ruining the rim.

Offline S. Heslop

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Re: Banjo Build
« Reply #76 on: May 21, 2015, 05:38:34 PM »

Routed the taper with this conical bit. Also did a fairly large roundover, larger than i'd have liked but it's the bit I had and the cone didn't reach far enough in.


Sanded.


Separated.


Flush trimmed the remaining bits inside. Always surprises me how accurate this bit is since it came in a cheap set.


Trust a camera and harsh lightingn to show up all the blemishes.



Gotta finish up the bottom since it's still got paper stuck to it. I forget what the max depth on my drum sander is but hopefully i'll be able to just send it through that. Although there's not alot of contact area with the conveyor with the fairly hard apple, so it might be better to just glue a bunch of sandpaper to a board and rub it against that for a while.

I think i'll save drilling holes in the thing till i've made the hardware to attach to it. I know how i'm gonna make the hooks and nuts since I made 50 of them in the past for this absolutely ridiculous (but pretty) rim.



But the L shoe brackets seem like they might be tricky without a mill. I had the idea in the past that i'd try lost wax casting them but since i've yet to successfully cast aluminium i'm not gonna try brass.

I might just have to spend a day making them the hard way with files. I'm gonna aim for about 24 hooks and nuts around the rim so that's not a huge amount for a one-off.

Offline S. Heslop

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Re: Banjo Build
« Reply #77 on: May 21, 2015, 05:51:36 PM »
Oh I tend to forget that I have a die grinder now. Found some carbide burrs at a boot sale last year and a 'laminate trimmer' I bought turned out to just be a die grinder with a plunge base. That'll probably make life easier.

Another thing I might be able to do is make most of the shape and drill the holes into a long bar, then cut sections off and tidy them up with a file. With it in a long bar I could also possibly rough the concave material out by putting a burr in the router table and making alot of passes.

The problem is is that I don't find the idea of sitting down for a day and doing it the obvious way particularly exciting. I'd rather spend weeks like I did with the rim in trying to find a 'clever' solution that will most likely backfire.

Offline vtsteam

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Re: Banjo Build
« Reply #78 on: May 21, 2015, 05:52:08 PM »
Hey, it's looking like the bottom of a banjo!!! :thumbup: :clap: :beer:
I love it when a Plan B comes together!
Steve
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Offline S. Heslop

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Re: Banjo Build
« Reply #79 on: May 21, 2015, 06:22:12 PM »
Hey, it's looking like the bottom of a banjo!!! :thumbup: :clap: :beer:

Thanks. And not a moment too soon.

I really hope the rest of it doesn't take me over three months.

Offline S. Heslop

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Re: Banjo Build
« Reply #80 on: May 22, 2015, 03:54:47 PM »
Haven't done much today in the garage. But I did test that burr idea.


Seems to work fine. I tried it first with aluminium and it clogged the burr in seconds, but I then remembered I had a square bit of brass (about 1/2" wide). Depth of cut is about 4mm. The cut was made fairly fast and the brass heated up a bit but not to the point that it hurt to touch. So I think this idea seems fairly viable for brass at least. Possibly cast iron too, and anything where the chips aren't gonna clog the burr.

The only concern I have is the brass chips falling into the router below. I might try cover the vents (will still have to allow airflow).

While waiting for a chance to buy the brass required I'll probably make the hooks and nuts.

Offline NormanV

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Re: Banjo Build
« Reply #81 on: May 22, 2015, 04:02:26 PM »
I've been following this with interest, I've made a Ukelele and a rough Guitar. I have an ambition to make a proper Guitar. What is the skin made from?

Offline chipenter

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Re: Banjo Build
« Reply #82 on: May 22, 2015, 04:24:45 PM »
TCT router bits work well on aluminum spray the cutter with wd40 to stop a build up .
Jeff

Offline S. Heslop

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Re: Banjo Build
« Reply #83 on: May 22, 2015, 04:47:28 PM »
I've been following this with interest, I've made a Ukelele and a rough Guitar. I have an ambition to make a proper Guitar. What is the skin made from?

Mylar plastic as far as I know. Some folk like to use calf or goat skin for an 'authentic old time tone' but I think that's silly. Skin heads tend to change tension with humidity changes and can sometimes burst from it, and they're awkward to fit from what i've read. I did consider getting some skin for that rim with the 50 hooks, since there wasn't alot of space between the rim and the hooks to fit the rim of the head. I ended up filing notches into it to get it to fit.

I also tried looking up using plastic sheet as a head material but couldn't find much information on it other than a few failure stories (mostly with it stretching over time until eventually breaking). Didn't fancy experimenting.


TCT router bits work well on aluminum spray the cutter with wd40 to stop a build up .

I'm concerned this router table won't be at all strong enough for any serious cutting forces. I figured that since I can control a burr with my arms no problem it won't have too much force to deal with.

Offline chipenter

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Re: Banjo Build
« Reply #84 on: May 23, 2015, 02:33:50 AM »
I have cut ally with a circular saw a planer and a router , no table or bench on site you don't have to cut it all out in one cut .
Jeff

Offline SwarfnStuff

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Re: Banjo Build
« Reply #85 on: May 23, 2015, 03:32:42 AM »
This has been and still is a fascinating thread. Thanks for posting.
John B
Converting good metal into swarf sometimes ending up with something useful. ;-)

Offline S. Heslop

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Re: Banjo Build
« Reply #86 on: May 25, 2015, 01:14:47 PM »
This has been and still is a fascinating thread. Thanks for posting.
John B

Thanks very much!

I've been hesitating to do much lately until I know what i'm doing. But I think i've finally got the general sizes and shapes of the hooks, nuts, and brackets figured out.

I dug out all the junk I used to make those 50 hooks a few years ago.


On the left is a test hook with a wider angle than what I used in the past. Then next to it is an aluminium block used for holding the hooks in the lathe so I could trim them quickly. Then is a reshaped chisel to act as the punch for the die on the right. The small slug of steel is something new that I've put into the middle of the die to limit the depth that the brass can go, so I can adjust the angle and hopefully keep it consistent.


Closeup of the fixture. Not much holds it in but the slight wedge where the short end of the hook sits. You can see a flat spot on the brass wire from the punch, there's one on the other side too. The hooks on an old banjo I was looking at a while ago had the same flat spots and i'd assume they used a similar method to produce them as I did.


I'm still hesitating to go full steam ahead and make all the hooks I need (and a few spares), since there's still a bit of doubt as to if i'm getting the dimensions right.

Offline S. Heslop

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Re: Banjo Build
« Reply #87 on: May 25, 2015, 04:36:22 PM »

Cut the rods to length. I need to clean my lathe at some point. The chuck isn't holding the rods, it's just at the end of its travel so I can pull the full rod out to touch it, and its then backed off a bit before cutting so it doesn't get in the way.



Next I need to thread them. My 4mm die came with a very cheap set from Lidl's, and the 4mm die unfortunately cuts noticeably undersize. I'm considering ordering a better quality one so my threads look a little less dorky. An M4 die costs 25 from Cromwell tools though so sod that. I might try getting one from arc euro trade, although it won't let me see estimated delivery times until I put my credit card details.

I think i'll check a couple of local hardware stores before ordering one for delivery. I'm impatient!

Offline DavidA

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Re: Banjo Build
« Reply #88 on: May 26, 2015, 06:05:48 AM »
Just wondering,  Would it be easier to thread all those rods using a tailstock die holder before bending them ?

Dave.

Offline Fergus OMore

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Re: Banjo Build
« Reply #89 on: May 26, 2015, 07:57:27 AM »
If your cheap Lidl die is cutting too much( and Lidl dies are only for restoration work) you can refresh the die.

Frankly, you have already entered into a discussion here about making a set of dies etc. in - in this case- gauge plate. If it were me, I'd check how corresponding tap behaved and if it needed reducing in size, it would be a dead easy task.

Yes? It is what we Geordies called in the Pitmatic- ettling

Regards

Norman

Offline S. Heslop

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Re: Banjo Build
« Reply #90 on: May 27, 2015, 04:55:33 PM »
I could've sworn I made a post last night about this. I must've forgotten to actually post it after previewing.

Decided to just use the die I have after remembering the prime directive; keep it simple. Doesn't cut as undersized as I remembered.


The die is pushed forwards with the face of the chuck. There's a steel slug held in it that stops the tailstock when it hits the bar, and the die starts moving away from the chuck. The lathe is reversed when this happens. My reactions aren't great but it kept the threads within about a millimeter's difference.


All marked for the bend.


And bent.


I thought i'd get away with bending them all at once with the shallower bend than last time, but this one broke. It was a rod that span in the lathe chuck when the die got clogged with chips (forgot to blow them out) so perhaps that work hardened it.


Annealing them part way through solves the problem.


Today I started cutting the front of them.



Started keeping them in these drawers too since they were starting to get lost.

Tomorrow i'm going to buy some brass for the L shoe brackets, and also a new length of stainless for the tension hoop since the steel I bought previously was 3mm thick when I really want 5mm.

Offline S. Heslop

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Re: Banjo Build
« Reply #91 on: May 28, 2015, 07:28:04 AM »
Finished up the hooks for now. Gotta polish them but I think I might go all out with a buffing wheel. I'm wondering what are the chances of the sharp edges of the hooks getting snagged on a mop? I was thinking I could make a handle to screw the hooks into to get more of a hold on them, but then I also think that it's just more mass to get thrown if or when they do snag.


You can see how inconsistent they are. I thought of a way to make the hooks more consistent but I think the way I did them is pretty fast. It took me a while because i've spent the last few days helping look after a baby. Babies are hard work!

The inconsistency might bother me enough to make me trim the obviously long ones but I'll wait till it's assembled before worrying about that.


Also made a carriage stop to help with making the nuts. I've wanted to make one for years but was saving it for when I eventually get a milling machine. I think in the past for the same job I just set the compound to 90 degrees and moved that back and forth, but it's fairly slow and I don't fancy taking chances with my ability to count the turns.


It's ugly as hell but it should work.

Offline vtsteam

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Re: Banjo Build
« Reply #92 on: May 28, 2015, 08:55:18 AM »
You're coming along quickly Simon, particularly with a baby to look after! I didn't entirely understand how the threading die operation in the lathe is set up and works, but it clearly did work well.  :thumbup: :thumbup: :clap: :beer:
I love it when a Plan B comes together!
Steve
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Offline S. Heslop

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Re: Banjo Build
« Reply #93 on: May 28, 2015, 02:21:04 PM »
The tailstock isn't... whats the word... clamped to the ways. Locked to the ways?

Anyways i'm just pushing it along with my hand to put pressure on the die, which starts threading the bar under power, and I keep some pressure on to keep the die fairly flat as it continues threading.

The tailstock chuck is holding a bit of steel bar, which I set to a specific depth within the chuck so that when the threads are completed the end of the brass rod contacts that bit of steel bar inside the chuck and prevents the tailstock, that im pushing, from continuing to move forwards. Meanwhile the die can continue moving forwards, and as soon as I notice this I set the lathe into reverse so it backs the die off.

The die holder contacts and slides along the lathe ways to 'drive' it. I remember when I first did this I thought i'd try and be all safe and proper, and turn the lathe chuck by hand using the chuck key, but quickly found out that it was incredibly slow and hard work.


The threading was fairly accurate. Not exact but more than close enough. The inaccurate step was putting the bend in. I did think for a while about putting some sort of stop to butt the bars against for putting the bend in, but then realised that I didn't know where to position the chisel. I think it would work alot better with a press. Perhaps I could've made some sort of arrangement to use the vise for pressing.

Offline S. Heslop

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Re: Banjo Build
« Reply #94 on: May 28, 2015, 04:42:11 PM »
Oh also it's my brother's baby so it's not a full time job, and i'm mostly just helping our mom out. She's just learned how to crawl very fast and it's quite frightening! Still alot of work only as part time.

Got set up to cut the nuts.

Using the turret tool post with the indexing feature, 2 profile tools, and the parting tool. The procedure this time is to screw the tailstock to the end of its travel and pull the bar out till it touches, then screw the tailstock back so it doesn't get in the way. Move the lathe to the right carriage stop then start with the profile tool to cut the 'chamfer' part in the middle, then turn to the profile tool to cut the round part. The round profile tool is kind of pushing it with what this lathe is capable of. Then a tickle with emery before moving the carriage to the left stop and parting it off.

There's some of those drawers under the lathe to catch the parts so it doesn't get lost into that mess I really aught to clean up. Not a fan of cleaning this tiny lathe since it more or less requires scooping the greasy crap with my hand out of the small space, then it gets all over the bench in front which has to be cleared off of the clutter so it doesn't get buried under the swarf.


Right hand carriage stop is just the carriage lock. I figure it won't have any problems with swarf getting in the way of it and the carriage like it would on the left.


Cutting the rest tomorrow. They're about 16.4mm long within about .1mm. I made an error on the lower left one, forgetting to index the turret and trying to part with the form tool since I was distracted with filming. And I kinda like the way it looks. I'm considering making the rest in a similar way.

When I made them the first time I drilled the holes in them during this step too, also did part of the profiling with a file and they all came out wildly different. I guess it has that 'hand made' quality but I think they look a mess. Anyways the drilled hole tended to drift after a few were made and needed to be started again, so i'm planning to just drill the holes and tap them as a separate process.

Also the rounded bottom isn't entirely decorative, and is more to stop them from digging into my thighs as much when playing the banjo.

Offline S. Heslop

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Re: Banjo Build
« Reply #95 on: May 29, 2015, 04:32:13 PM »
There was nothing thrilling about this drilling~♫


It was a long process, and so were some of the previous ones, but what made this one especially tedious is that it would've gone so much faster with a camlock tailstock and a keyless chuck. Almost all of the time spent was undoing the tailstock screw.


Got 28 done. Unlike previous steps i'm not compelled to finish off the spare ones since it didn't use a fancy setup. I can just make another one from the few unfinished spares if something goes wrong.


At first I was drilling a 4mm deep clearance hole above the threads, since it looked neat. But I realised after doing a few of them that way that it was hard to tell the difference once screwed on.


Next I've got to polish them. Still waiting for the brass to make the shoes. I've got no real polishing equipment and i'm considering trying to make my own mops by stitching together a bunch of old clothes. The other alternative would be to try tumbling them with some builder's sand. Not fussed about getting a high shine or anything since brass eventually tarnishes and looks like crap anyways.

Offline vtsteam

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Re: Banjo Build
« Reply #96 on: May 29, 2015, 04:39:05 PM »
I was sorta thinking of a banjo as a woodworking project, but I'm starting to think it's metalworking project with some wood bits attached! Keep up the good work!  :thumbup: :beer:
I love it when a Plan B comes together!
Steve
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Offline S. Heslop

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Re: Banjo Build
« Reply #97 on: May 29, 2015, 05:00:42 PM »
You could always just buy the hardware ready made.  The hooks and nuts are about 1 Canadian dollar each. Although the shoes are $4.

Boy that's almost $160 for a 28 hook rim, but it probably isn't too far off the materials cost. 28 hooks is also way more than you need, I just think they look nicer with more.

That 12" rim banjo with 50 hooks is very silly though. The big problem with that many hooks is that there's hardly any tension on each individual hook. So the nuts tend to work their way loose. I read that there was a period of history where banjos underwent a hook war because, like with everything else, the bigger number means a better product. Supposedly they got up to 60 hooks on an 11" rim before people realised how ridiculous it was.

Offline S. Heslop

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Re: Banjo Build
« Reply #98 on: May 31, 2015, 03:42:54 PM »
Knocked the edges off and shaped them a bit with some emery cloth stuck to a bit of wood.



I was planning on making some wheels as an excuse to use the sewing machine, but I was looking for the compounds and the only local place I could find that sold them was Halfrauds, who sold them in a kit with some tiny wheels and an arbour. I thought they worked pretty well though, the arbour had a left hand screw so it didn't loosen itself when rotating in a drill chuck.

Maybe Cromwell stocked them but it's a bit awkward to get to.


The sides of my fingers are also nice and shiny.


Made the handle to hold the hooks but I just found it awkward. With a bit of threaded rod in the end it could hold the nuts, but a problem is that the threaded rod tends to come loose. I'm waiting for the loctite to dry before finishing the nuts. If that comes loose i'll just turn the other end and make the threads one piece.

The sad thing about getting brass this shiny is that it's not going to stay so for very long. It's tempting to lacquer them but then that'll probably wear off and look tacky.

Offline Fergus OMore

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Re: Banjo Build
« Reply #99 on: May 31, 2015, 04:09:45 PM »
From where I sit might I answer a couple of issues.

The first is that mop cloths are usually stapled together because unless you have a boot patching machine or better, you'll bust a normal domestic machine.  I did tent making  or more correctly, repairs in canvas tents for the Scouts in Workington. You need saddle making needles and protection for your hands. See a sailmaker - like Tommy Owen. I think that the old firm is still around somewhere.


As far as brass lacquer is concerned, my daughter has just phoned us to say that she has bought a piano. Her Mum is going to die just yet and she will not the 7/8th Bluthner Grand yet. Tough but it poses the point that the Bluthner has its second coat of lacquer - since 1911.

Good lacquers are still available  for Saxophones and so on and Ferries of the USA are still the best although people like Windcraft in Cambridge are pretty good.
My mates DO wind instruments and I have lacquer but that is not for general exposure.

Ferries cat. is compulsive reading, by the way.


Norman