Spirals

[JimGo]

How do you turn a spiral? I saw a pic in WoodScavenger's pics that included a spiral shape in the outside of the pen, and can't imagine how to do this other than by hand (for example, as Tom McMillan described here http://www.penturners.org/forum/topic.asp?TOPIC_ID=3564). Does anyone have any suggestions? Obviously, this is a bit beyond my current capabilities, but I hope to get there some day!

Any ideas are appreciated!

 

[btboone]

CNC is a good option. [] Actually doing it by hand would not be so bad if you had a super slow speed on the lathe, something like 30 rpms. Short of that, filing by hand as the pen is turned by hand like Tom does it is the best way to go. Another technique that's possible but may be tricky to get nice results with is the beadblaster option. Also, metal lathes have threading capabilities, but I don't think most of those would go to such a long pitch.

There may be a way to wrap a flexible turning guide, like a thin sheet of stainless steel around a pen in a helix. About the size of a hacksaw blade but thinner. The tool would follow the edge like a pencil follows a ruler when drawing straight lines. That's a long shot though.

 

[DCBluesman]

Milling machines offer a mid-price alternative to CNC and metal lathes. The Beall Tool Co.'s Lathe Wizard and the Legacy Ornamental Mill are a couple of alternatives to look into.

 

[JimGo]

Wow, those are cool! WAY outside of my price range, but cool!

 

[btboone]

Very neat products, that's for sure. It looks like the ornamental tool only does long pitches like 1.5" for the less costly models. Does that sound right Lou? I saw where you could get some different gears, so maybe pitches like 3/8" are possible. I didn't see examples like pens for the lathe wizard. I assume it can do the same kinds of things?

 

[DCBluesman]

I'm going to see it this weekend, Bruce. I'll report back.

 

[btboone]

exotic tools. gotta love em.[]

 

[woodscavenger]

From the horses mouth. Others have done much a much better job than I but since you asked here's what I did.

1. Start with a beautiful burl.
2. Create you basic shape, finalize the end sizes and decide to take one more little shave off
3. HAve a nasty skew catch.....this created a spiral about 2 turns with the spacing you saw on my top tube.
4. Mope for a couple of days about how beautiful it could have been
5. Dream about having a CNC machine or metal working lathe with slow speed threading capabilities
6. Remount the blank.
7. Use a small triangle shape file and follow the basic spiral slowly up the length of the blank with an initial scratching then slowly hand file it to whatever depth floats your boat.
8. For the bottom I got a little more scientific. I used a razor knife and held it on the blank and braced it on the turning rest. I eyeballed an angle....about 20degrees and held the knife in place while turning the blank by hand (reverse direction...wood turning away from me) and as the blank turns, the angle of the razor will scribe a beautiful spiral pattern.
9 Repeat step 7

I am sure there are better ways and I will try them sometime. For now I call it a good save. Thanks for the interest.

 

[btboone]

Woodscavenger, how slow can your lathe go? I assume on step 7 that you did that under power? Did you really have to chase after the line or was it going a comfortable speed?

 

[Tom McMillan]

My understanding after emailing Legacy was that the small Legacy would only do the 1.5 inch pitch, and to my understanding no others were yet available for it---although there are other models, and I'm not sure of their capability and are a bit spendy. Another tool I was going to set up to turn spirals was the old Sears Router Crafter,---Sears no longer makes them----but, they are still made in England called the Trend Router Lathe. I ordered a part for it from Woodchuckers from Canada and they got me one from Craft Supplies of Enbland. I've since sold it because it would have had to be adapted for pens---I don't know how tight a spiral it woud turn either. Another tool I had (didn't use it and sold it too)---was the Sorby spiralling tool. I was told by a couple of dealers that it wouldn't work for pens---but, I emailed Sorby and they told me they thought it would work for some pens. Not sure if anyone here's used one?? Also, Alice used the Legacy---did she buy one??? Alice, any info??? If all else fails---I've really found it fun to make the spirals by hand and I'm kind of glad I had the opportunity to learn it---even though I do yearn for one of the Legacy or Beall tools. Another tool Woodcraft used to have was the Mill Lathe made for pens for spiraling and other capabilities for pens---unfortunately it's not available anymore unless you could happen upon a used one.

 

[woodscavenger]

I just got my new jet mini VS but I forgot about that option when I did this spiral. My old lathe low end was 600rpm. I didn't even think to power chase it.....hmmmmm. It was all under old fashioned elbow grease. It was actually pretty easy. 3-5 strokes, turn about 1/8th turn and repeat all the way up then back down.

 

[JimGo]

Thanks guys! WoodScavenger, FWIW, it came out GREAT!

 

[btboone]

Hand filing is probably the safest way anyway.

It doesn't look like engineering a machine like Lou referred to would be that tough. It could be a hand cranked thing that drives a nut along an all-thread rod while pulleys attach the all-thread to the slower rotating main mandrel that the pen rides on. Depending on the pitch of the all-thread, a pulley reduction of something like 1:8 might be used. This means 8 cranks of the handle would drive the nut 1/3" while the pen rotates once if 24tpi all-thread is used. The nut that rides on the all-thread could pull a sled with a Dremel tool back and forth.

 

[jwoodwright]

I know I haven't lost my mind, there was supposed to be a Oramental Mill that mounted on the Jet Mini and did spirals and such with a laminate trimmer.

The info on the Legacy sounds like a stand alone machine, even the smaller one with laminate trimmer...

Dreaming [?]

 

[JimGo]

Bruce, I get the feeling you've done this before... Need help with the design?

 

[DCBluesman]

I'm thinking more along the line of the (greatly over-priced) Foredom tool, primarily due to the fact that it has a 1/4" chuck. The 3/16" max of the Dremel is VERY limiting.

 

[JimGo]

How about something like this? http://www.theokspindoctor.com/framewelcome1.html

 

[btboone]

I'm just doing some napkin sketches. This thing is easily doable for a Dremel tool. The Dremel can handle ball type cutters that are larger than the shaft. You could use a 3/16" ball and only plunge to half depth. I have it so you can adjust the depth of cut. The whole thing is made with allthread and maybe a block of plastic or aluminum (maybe even wood) for the nut part. This deserves a CAD drawing.

 

[jwoodwright]

Nice... Now a Mini Lathe version... Thanks for the link...

 

[DCBluesman]

I'm fairly certain you're referring to the Lathe Wizard and gear drive assembly. Check it out at http://www.bealltool.com/lathewiz.htm

Originally posted by jwoodwright
<br />I know I haven't lost my mind, there was supposed to be a Oramental Mill that mounted on the Jet Mini and did spirals and such with a laminate trimmer. Dreaming [?]

 

[elody21]

Tom, I did end up buying one! I am still waiting for it to come. They do not have them to take home at the wood show. I'll let you know when it comes!
The legacy 200 only does one pitch there are no opions for this model, You can different bits to change the look. You can do reeds and beading.I have a lot of ideas of things to try. I also plan on making pillars in white Corian for wedding cake stands. "I design and make wedding and party cakes" It also come with templates for duck calls, candle holders etc.. It will be interesting to see what it can do.
I will be sure and inform everyone how it does when it comes in.
I had the Beall lathe wizard. I did not like it and sent it back. It ran on a Dremmel instead of a laminate trimmer and to get everything to do sprials it is at least $100.00 more that the Legacy 200!

To Be Continued..........

Sorry guys, My order for the Legacy 200 was delayed by a month. In that time I reliezed that I did no need another toy! So I cancelled the order before it was even shipped!

 

[jkirkb94]

There is an example of turning spirals on pens using a Legacy machine in Turning Pens and Pencils by Kip Christensen and Rex Burningham. This book helped me in my earlier turning days. Kirk[8D]

 

[Fred in NC]

Just my take, ok ?

In this day and age of CNC such mechanical devices are outdated.

I think Bruce would agree with me!

 

[JimGo]

but cnc takes away the "hand made" quality of the pens!

 

[Fred in NC]

Right, Jim, it does ...

Let me ask this, what did Bruce use to make his titanium pen?

 

[DCBluesman]

Each generation talks of taking the "hand made" quotient away from the art. I've talked to one gentleman from Richmond who told me the exact same thing about motor driven lathes as he continued working on his treadle model. (He's over 80 at this point and still turning.)

Originally posted by JimGo
<br />but cnc takes away the "hand made" quality of the pens!

 

[Fred in NC]

I was just talking about the Legacy, Lathe Wizard, Router Lathe, and other similar <b>rotary milling</b> machines. The capabilities of these machines are usually limited by a design based on gears and pulleys. The ratio of the spirals is based on gear changes. To me the technology used in these machines is obsolete. Still they are usable machines that serve a purpose.

Electronics and servo <b>or</b> stepper motors (they are not the same thing) could greatly improve the range of spirals and designs that can be made with a rotary mill. At the very least, the ratio of the spirals could be made variable.

I can understand the limitations when a manufacturer is trying to sell a piece of equipment for about $400. There is no way they can sell controllable motors and electronics in that price range.

However, when you talk about a $5000 machine the situation changes a great deal. That kind of money can buy a mechanical machine <b>or</b> a woodworking CNC router. A <b>woodworking CNC rotary mill</b> is feasible for such a price. I will not be surprised if Legacy, for example, introduces such machines in the near future.

<b>Most</b> of the work we do is better done by hand in a wood lathe, especially talking about one of a kind pieces. What I can do with a chisel in my Jet Mini in 5 minutes would take a lot longer to program in CNC. Once programmed, that is exactly what a CNC machine will cut. There is no allowance for last minute changes (unless you change the program).

On the other hand, I could drill the holes with an egg beater (hand drill), and use a rasp to shape the barrel. Handmade? NO! look at the metal parts !!!!

 

[btboone]

&gt;In this day and age of CNC such mechanical devices are outdated.

True enough Fred, but the cost is a huge issue. As I said, I have a design for a spiral cutting machine like those that could be made for something like $25 to $50 from easy to find parts. It would be a lot less flexible, but should be able to do some basic spirals. I still need to draw it up. I've been a little busy lately. [] Obviously, I don't need one since I have a couple 4th axis machines, but if anyone might be interested, I'd be happy to draw up what I have in mind. I need to catch back up on rings in the short term though.

 

[woodscavenger]

Bruce, any sketches would be wonderful. Thanks for even thinking of us lowly people without a 4 axis machine. Now exactly what is a 4 axis machine. I think back to my basic geometry and can think the X,Y,Z coordinates. The 4th one? Is it that you can finally travel through time and do these things faster? []

 

[Fred in NC]

Basic MILLS have 3 axes. Standing in front of a mill and looking at it, these are the primary linear axes:

x moves right and left
y moves to and from you
z goes up and down

The Electronics Industry Association (EIA) has defined the following ROTARY axes. They are just ways to describe motion around the respective axes:

A rotates parallel to the x axis
B " " y
C " " z

A vertical rotary table at the left of the mill's table, for example, would rotate on the x axis, and would be considered a fourth axis. This is a very common arrangement for cutting gears. This is also very commonly referred to as a FOURTH AXIS.

Sorry no pics at this time.

 

[btboone]

Yup. Fred nailed it. A controlled rotary axis. Kinda like a lathe axis under a milling machine, but controlled rotation just like the other axes.

 

[Tom McMillan]

Bruce---I would be very interested in the design you're thinking of for a spiral machine---if, and when you have time to do it. I don't agree that machines like Legacy and others are outdated at all (especially for penmaking)---when they get a CNC down to $400 or $500 maybe then. Heck, it would seem like the old Sears router crafter would be outdated (although still made in England by Trend)---but they still sell for much more than they cost new on EBAY. I'm sure most of us couldn't consider a CNC machine because of the huge cost. But, remember Bruce, I'm still open to that "apprenticeship"!!

 

[JimGo]

Yes Bruce, PLEASE post anything you have. I'd be happy to work with you on the design, too.

- Jim

 

[btboone]

I'll do that Jim. I've got about 20 rings to get through tomorrow, but I'll try to get on top of them soon.

 

[JimGo]

No rush Bruce. I'd just love to see what you have in mind. BTW, your rings are AWESOME!

 

[Paul in OKC]

Originally posted by JimGo
<br />How about something like this? http://www.theokspindoctor.com/framewelcome1.html

Hey, I've been to this guys house[]. Don't remember if he had one of these done or not though.
I'd be willing to help on this project if any extra is needed. I agree that one could be made very reasonable.

 

[btboone]

Paul and Jim,
I should be able to draw up something workable. I'll need someone with some manufacturing savvy to help sweat details to help make it workable and more manufacturable. Instead of toothed belts or gears, which are both fairly expensive, it might be possible to use a couple O rings in homemade pulleys to drive the pen shaft. Stuff like that needs to be proven out before it's ready for the masses.

 

[Paul in OKC]

Originally posted by btboone
<br />Paul and Jim,
I should be able to draw up something workable. I'll need someone with some manufacturing savvy to help sweat details to help make it workable and more manufacturable. Instead of toothed belts or gears, which are both fairly expensive, it might be possible to use a couple O rings in homemade pulleys to drive the pen shaft. Stuff like that needs to be proven out before it's ready for the masses.

Making the proto-type is no problem. I had thought about plastic gears, but may be too costly as well. As long as the depth of cut wouldn't pull and cause the belt to slip. Making pulleys is no problem, could make a couple of steps for different pitches if we want. I have access to some larger o-rings at the shop. If they are not long enough, we buy them locally so it would be easy to check size.

 

[btboone]

Paul, the issue is the 8:1 ratio. Gears would be great, but they are expensive to get from most places. A source for cheap ones might be in toys or other molded plastic parts. For O rings, there would have to be several of them in tandem. The good news is that the hard to turn shaft that drives the nut is directly rotated with a handle. The geared down one (thus mechanically advantaged one) will be the pen rotating. The distance of the nut traversing shaft needs to be somewhat close to the pen spindle so the Dremel could be as close as possible to the pen. If the larger gear or pulley is 2" diameter, this only leaves 1/4" diameter for the smaller one, so it will have to be a good grip and multiple O rings to be sure. A higher helix will need an ever higher drive ratio.

 

[Fred in NC]

What pitch leadscrew are we talking about?

Acme rod comes in pitches that are more suitable for this purpose, like 3/8-8. Then the pulley ratio can be smaller.
Cost is under $3 per foot at McMaster. A nut costs a couple dollars.