[Woodworkers] Copper metal working

Richard Allen rla_buy at yahoo.com
Tue Apr 20 16:33:46 PDT 2021


Hi Chuck,

The design looks great and very involved.  Don’t you love the way Bolivian Rosewood works?  I find that dense wood are easy to get a great finish.  #8 is small for holding the copper rod so care, sharp tools and light cuts will help.  I would make a point of cutting towards the headstock.  That is to say that the force of the cuts should be toward the headstock.  Those sorts of cuts will tend to be more successful as the force of the cutting is pushed back by the headstock.  Cuts in the other direction are supported mostly by air...  The metal cutting bits I have seen tend to hold onto the edge longer.  But that edge tends to be more dull to start with.  Those bits also need a lot of support.  Keep the diamond hone handy and sharpen the top edge with the hone often.

> On Apr 20, 2021, at 6:14 PM, chuck.steger at gmail.com wrote:
> 
> 
> Richard,
>    Thanks for the tip!
>    The following will go under the heading of “more than you asked for” 😊
>    The plans are drawn to scale except for the crude isometric view. If you can see the yellow, that is to represent the bamboo and the red is the Bolivian rosewood. Copper rods and sphere are also shown. After receiving the material, I decided to reverse the wood (I’m calling the bamboo wood even though it is really a grass). The bamboo is much lighter and that helps me on the top. Besides, I got a really nice board of Bolivian rosewood that will look really good on the sides. The rosewood is real dense so it is much heavier than the bamboo. One of my concerns with the bamboo was sculpting the curves in the top. As you all probably know, bamboo has to be glued together to achieve the wide stocks. It can be glued horizontally and you get the traditional look of bamboo with the nodes and all. Another way is to glue it up sideways so as to appear as quartersawn. Since I anticipated using the bamboo for the top, it had to look good sculpted. Horizontal bamboo is like plywood and you would see the layers. I chose the straight grained look and routed a profile to see what it would look like and it really looks like quartersawn wood.
>    On the curved top, my first attempt was to cut successive kerfs in the top (at different thicknesses) and then hand plane it with a curved plane. Going with the grain worked well but against the grain looked bad. I decided a TS cove was my best bet but I had to figure out what my diameter was on the curved top. The jpeg is how I figured that out. It’s a 15 ½” diameter circle so I knew that didn’t bode well. The drawing also let me determine the dimensions I needed for the cove calculator. There are a number of ways to figure out the angle for a TS cove. There is a calculator online http://thewoodpecker.net/cove/cove.htm but every time I input my numbers, it threw up on them! I was researching how to do it when I read an article where the person said he just sights down the TS and board until it looks good, then match that angle. That works surprisingly well. I knew I couldn’t get my exact curve but it looked like I could get close. It put a bit of a lip on the edge which actually looked more Asian (bonus!). However, that look worked when you did the ends of the top but when you did the sides it knocked off some of that lip. I have to do some sanding to even that out.
>    At this juncture I decided to work on the sphere. So update to that is I bought some threaded steel rod for the sphere. But while I was out, I was looking for a #29 drill bit. That is the bit you need to thread #8-32. I used a 9/64” which is .140. A #29 is .136. Now, is .004 enough to make a difference? I don’t know but I want as much thread purchase as I can get (plus, I’m anal, so there’s that!). The big box stores do not carry those types of drill bits. I ended up going back to the house and rummaging through a box of my dad’s drill bits and found 2! While I was out, I found some metal working cutters for use on a metal working lathe. I asked the guy for handles but he said there aren’t any because they are supposed to be attached to the lathe in a cutting holder (makes sense). I bought them anyway and am figuring out if I can make a handle. But before I do all that, am I barking up the wrong tree? Will that not give me any advantage? Waste of time? I have to say, I’m closer than I thought on the sphere, I just need to make it a sphere and not a cylinder.
>    I should have pictures of the prototype soon. I need to finish the sphere so I know the dimensions of the sphere holder. Plus I’m making a drilling jig for my legs and box since the rods have to match perfectly at all the same heights (and there are 3 different diameters of rods).
>  
> Chuck
>  
> From: Richard Allen <rla_buy at yahoo.com> 
> Sent: Monday, April 19, 2021 3:22 AM
> To: woodworkers at sawdusters.org
> Cc: chuck.steger at gmail.com
> Subject: Re: [Woodworkers] Copper metal working
>  
> Hi Chuck,
>  
> Good to hear you are having FUN.  Fun is the goal.  The object is result of fun and something you can point at (even if only in your mind) to help remember the fun.
>  
> If you aren’t working with a burr then a diamond hone on the flat top of the scraper can bring back the edge quickly with a few strokes.  Just lay the hone flat on the top of the scraper and slide it back and forth a few times.
>  
> I would love to see pictures of the design and progress.
> 
> 
> On Apr 18, 2021, at 10:56 PM, chuck.steger--- via Woodworkers <woodworkers at lists.sawdusters.org> wrote:
> 
> 
> Not a lot of woodworking traffic so I thought I’d bore you with an update. But first, it really does take a village – this woodworking village has some great knowledge and is always there to help! Thank you all!!
>  
> I have 2 HSS round nosed scrapers with 2 distinct angles. They say 65 degrees is optimal but there are other angles for other applications. Mine are about 80 degrees and about 60 degrees. The 80 would have more steel behind it but the 60 should cut better. Interestingly enough, the 80 cuts the best so that’s what I’m using. I sharpen often and was taking time to create a burr (since it is a scraper) but I’ve ended up just sharpening and going back to turning and that seems to be working. I got it down to a cylinder (less than 7/8” but not at the desired ¾” yet). I wanted to see if I could turn it back to a sphere so I backed off the tail stock to round over the end and had a catch and the sphere went wobbly. I immediately turned off the lathe thinking the sphere was about to come off but after inspection, I found the rod had bent. Being a typical woodworker, I used what rod stock I had and in this case was rods from yard signs. I knew it wasn’t quality steel but had hoped it would work. It didn’t. So, tomorrow I’m off to the big box store to buy threaded #8 x 32 steel rods. For grins, I weighed the sphere which started at 3 oz. and is now 2.1 oz so just in what I’ve done I’ve shaved about an oz off the weight. I figure when I’m done should have it down to 1 ½ oz or less. This is great news for me as I thought the original was a little too heavy. I am making a prototype and have the box part done and most of the lid. My design has large curves in the lid which concerned me on how to make the curves. My first thought was coves on a TS but the curves were too big for even that. However, I sighted down the prospective cove path and knew I could get close. Sure enough, it came out pretty good (with some hand sanding involved)! It didn’t exactly match my drawn design but it is so close that I’m calling it good! The beauty of an original design is no one knows what it was supposed to be and it’s okay to call an auditable! Heck, I may end up doing that with the sphere. Of  course, now you all know so mums the word 😊.
>  
> Anyway, there’s a lot of learning going on and that’s a good thing. My last few projects had me doing new techniques which I love doing as I expand my skill set.
>  
> Thanks again!
>  
> Chuck
>  
> From: Steve Bigelow <sbig333 at gmail.com> 
> Sent: Saturday, April 17, 2021 6:37 PM
> To: Chuck Steger <chuck.steger at gmail.com>
> Cc: Sawdusters <woodworkers at sawdusters.org>; Richard Allen <rla_buy at yahoo.com>
> Subject: Re: [Woodworkers] Copper metal working
>  
> Yes, that should be a positive rake, unless you're sharpening top and bottom. 
>  
> On Sat, Apr 17, 2021, 4:19 PM <chuck.steger at gmail.com> wrote:
> Steve,
>    Thanks. I have a round nosed HSS scraper. I sharpen it on a Wolverine system matching what I had when I bought it. That’s a positive edge, right?
>  
> Chuck
>  
> From: Steve Bigelow <sbig333 at gmail.com> 
> Sent: Saturday, April 17, 2021 3:35 PM
> To: Sawdusters <woodworkers at sawdusters.org>
> Cc: Chuck Steger <chuck.steger at gmail.com>; Richard Allen <rla_buy at yahoo.com>
> Subject: Re: [Woodworkers] Copper metal working
>  
> The Easy Wood scraper is a negative edge scraper. I'm not an expert, but I've had better luck with a positive edge scraper and copper.
>  
>  
>  
> On Sat, Apr 17, 2021, 12:06 AM Richard Allen via Woodworkers <woodworkers at lists.sawdusters.org> wrote:
> Hi Chuck,
>  
> Because drilling is done without being hand held (drill bit fixed in the tailstock) you can work at much slower speeds.  300 rpm would be my choice for drilling.  For turning with a hand held cutting tool I would turn as fast as the lathe felt stable.  An out of balance hunk of copper might not work at 3000 rpm.  But as the copper became more balance I would increase the speed.  Please keep in mind that with an increase in speed there is also and increase in danger.  If the “Danger Zone” is 4” wide at 300 rpm I would establish a danger zone of 12” wide at 3000 rpm.  This is to say that none of my body would enter that danger zone and my head would double that distance.  Tool forward with arms outstretched and my head either past the headstock or past the tailstock.  If I needed a better view it would be done with the lathe off.  BTW I use this “Danger Zone” approach to all my turning except for spindle work.
>  
> 
> On Apr 16, 2021, at 8:17 PM, chuck.steger at gmail.com wrote:
> 
> 
> Richard,
>    Thank you! What do you think of the drill speed? 3000? Also, if I turn faster 2000? 3000?
>    Thank you for your help!!! Learning new things is exciting!
>  
> Chuck
>  
> From: Richard Allen <rla_buy at yahoo.com> 
> Sent: Friday, April 16, 2021 6:42 PM
> To: chuck.steger at gmail.com
> Cc: woodworkers at sawdusters.org
> Subject: Re: [Woodworkers] Copper metal working
>  
> Hi Chuck,
>  
> I would turn much faster.  Though I would be concerned about high speed and the brittleness of a carbide cutting edge.  Metal work tends to be done at a slow speed.  Slow speed is also counter indicated with a hand held tool as a hand held tool tends to move in response to cutting.  Expect a lot of noise but the higher speed should help make the cuts very light and soon the thing will be running true.  Once the thing is running true you should be getting ribbons.  You want those ribbons to be small.  The goal is light cuts.  Sharp tools help a lot and dull fast.  I use HSS so I am not sure how a carbide tool would work or how long the cutting edge would remain sharp.
>  
> Safety!!!  Always stand to the side while turning.  If the “bullet” should “dismount” you want to see it fly by not fly into you.
>  
> 
> On Apr 16, 2021, at 7:03 PM, chuck.steger at gmail.com wrote:
> 
> 
> Richard and all,
>    Follow-up on the copper sphere:
>    I drilled the sphere and did fine. But my first question is what is the proper drilling rpm for copper? Everything I’ve seen on the internet (9/64” drill bit) says 3000 rpm. That just seems fast to me. I ended up drilling at 1200 rpm and did fine (using 3-in-1 lubricant). But should I have used 3000? I will be doing more.
>    I threaded the sphere and a steel rod and screwed the rod into the sphere. I mounted the sphere on the lathe and used the tail stock to start but will eventually have to back off the tail stock. I used an Easy Tool scraper and started to turn the sphere. It was a little wobbly as I’m sure I didn’t hit the exact center of the sphere. When I gently entered the cutter to the sphere I got small chips and a lot of noise (I’m sure because metal on metal and a little wobble). I stopped turning because a 3 oz ball of metal coming off the lathe makes me nervous and decided caution was the better part of valor so I could seek more advice. The lathe was turning around 1200 rpm. Faster, slower? What type of chips should be coming off? The DP created longer wisps of copper and I was hoping for the same at the lathe but probably not realistic. What did cut was very rough. Sound normal so far?
>    I had safety glasses and a face shield on and I know wood coming off a lathe can do damage but when I think of this sphere all I can see is a big bullet ☹.
>    What do you think? Soldier on?
>  
> Chuck
>  
> From: Richard Allen <rla_buy at yahoo.com> 
> Sent: Tuesday, March 30, 2021 4:19 PM
> To: woodworkers at sawdusters.org
> Cc: chuck.steger at gmail.com
> Subject: Re: [Woodworkers] Copper metal working
>  
> I have turned copper on a wood lathe before.  I would take a 7/8” rod about 2” long an turn a sphere at one end.  The end being held by the lathe could be turned down to a suitable diameter so the sphere would be attached to the rod as a single piece of copper.  Another option would be to drill and tap the 1” sphere and thread some of your 3/8” rod to screw into the taped sphere.  Copper drills fine.  Plan on discarding the drill bit as sometimes the copper will “weld” to the drill bit.  I would do the drilling with the 1” sphere in a chuck on the lathe.  I would turn down the 1” sphere by mounting the 3/8” rod in a chuck on the lathe.  Copper turns with a scraper.  It is a fairly slow process but 10 minutes of scraper work and 15 minutes of sanding and polishing should give you a sphere shape to your likening
>  
>  
> 
> On Mar 30, 2021, at 5:02 PM, chuck.steger--- via Woodworkers <woodworkers at lists.sawdusters.org> wrote:
> 
> 
> Hope everyone is safe and healthy!
>    I need some advice on working solid copper. I’ll give you some context on what I’m doing.
>    I designing and building a Heritage Box for someone. Everything that goes into the design and construction will have some elements from their cultural background. Their mother and grandparents lived and worked in a copper mining town in Chile and copper was a big part of their lives. To bring copper into the design, I will attach the legs to the box using copper rods. Since the legs taper, I will use 1/8”, 3/16”, and ¼” rods and leave a ¼” gap between the legs and box. But this is subtle and I wanted to add something else. So I want to add a copper sphere at the top of the box. I drew up the design full scale and the sphere looks good at ¾”. So, I started researching copper spheres and what I found are jewelry spheres ½” and less or solid spheres 1” and greater. I ordered the 1” spheres which are actually used for plating copper.
>    So here are some of my issues/questions/concerns:
> Is there any way possible to reduce the diameter? I thought about some kind of holding contraption on a lathe and then using files but that just sounds like a bad idea.
> The sphere weights in at 3 oz. Now that may seem light but it’s a little heftier that I wanted because I don’t want it to tip the box over when hinged open. The box footprint will be 8”x12” so it may be OK. I will build a prototype as I always do so I’ll find out. Also with a prototype it will be easy to see if 1” is too big. A ¾” hollow sphere would be perfect but I can’t find that.
> Will solid copper drill OK? I would like to drill a hole for a rod to anchor the sphere to the box. I will epoxy the sphere to a cradle but a rod would be so much more secure IMO. And, given the weight, I would feel better.
> Here’s another take …. Is there a way to cut the sphere in ½” I only have WW bandsaws so even with a metal blade, WW bandsaws run too fast, don’t they? The thought process here is maybe I take the two half spheres and attach them to the side of the box as an adornment. The design will be mostly Asian so spheres might look good.
>    So you can see the design is in total flux. I’ve started building the prototype out of pine.
>  
> Chuck
>  
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> <Front-Back View.pdf>
> <Isometric View.pdf>
> <Side View.pdf>
> <Top View.pdf>
> <Diameter of curved top.jpeg>
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