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using a lathe the put frog end octagon in Bow stick

 
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jokorum
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Joined: 27 Oct 2009
Posts: 8

PostPosted: Wed Oct 28, 2009 5:25 pm    Post subject: using a lathe the put frog end octagon in Bow stick Reply with quote

Hello all... I am new here and very new to Bow making.

Could anyone give me some hints about lathes and how you can cut the Octagon faces on a bow stick at the frog end... I have been given some blanks by a friend and they are cylindrical as apposed to square.

I have been teaching myself how to make the Octagon with just a plane and a bit of logic, but I would be interested in finding out how to do it with machine to ensure that at least the frog end is perfect.

Also... same general topic. At the moment I actually have no mechanical hardware and know nothing about it either (violinist all my life) and I was wondering if you people might share with me some names of Lathes and parts needed to do what I have asked and also for drilling the screw hole.

Between you and me, I actually didn't know you could use a lathe for this but there we go!

So... what types of lathes and parts (and same goes for screw hole drilling) should I be looking out for. and assuming it is possible, do all lathes have a clearance space at the machine end for a rod of Xmm diameter to be stuck through before they sit butt end in the lathe chuck or am I looking at very specific types of lathes

Thanks in advance to all and any!
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Andres Sender
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Joined: 23 Mar 2007
Posts: 275
Location: N. CA

PostPosted: Fri Oct 30, 2009 3:48 pm    Post subject: Reply with quote

Normal professional practice involves starting with flat stock, cutting out the blanks, planing the blanks to rough dimensions square, then cutting the facets to make it octagonal by hand, then possibly rounding the stick.

I am not aware of anyone doing the facets by machine but probably somewhere someone is doing this--maybe in factories.

Which lathe to get I can't help much on, it seems like every bowmaker has a different machine. They usually use metal working lathes of course. I've seen Sherlines, Unimats, Chinese brands in various sizes, old South Bends, etc.

Many makers drill the hole with a bow maker's drill, which you can find illustrated on Lynn Hannings' site. Probably not something you want to try on your own though.

It is possible to drill the hole for the screw on a drill press, but doing so involves risk and you have to work out a system for clamping accurately.
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jokorum
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Joined: 27 Oct 2009
Posts: 8

PostPosted: Fri Oct 30, 2009 4:28 pm    Post subject: Reply with quote

thanks for the reply...

I know what you mean about the stock normally being square, sadly mine aren't...DOH! good wood though! 5500 and 5600 lucchi.

I am actually a player, so I understand the basics and the importance but not really the practice.

As with the drilling, you have any ideas concerning this and positioning exactly? I am at a loss.... of course the same would apply with a bow drill ( yep, as seen on Lynn Hannings) how on gods earth do you center the drill bit????

Concerning the Lathe....do all lathes have the clearence of lets say an inch in the machine stock for rods or even square stock to be pushed through to work on the Butt end to drill the frog screw hole and cut the nipple?

anyboby else out there with any ideas concerning Octagonal face cutting with a lathe would be most welcome..... I have read it somewhere that it is possible, but I think you need to alter the lathe slightly or simply add a circular plate to the machine chuck and have every 45 degrees some type of sold stop point to be able to cut (or rather slice) with the cutting tool the faces... slowly taking off microns until the desired depth is achieved..... but again I don't really have anything more than this.

Thanks very much Andres... anymore halp would be greatly appreciated.

ps. how would you go about drilling with nothing special and cutting the nipple.? I can only think of making a miter box setup and placing the butt end (after the screwhole is cut) on a stopper and having the saw in the miter box set to a depth that cuts the desired nipple whilst you basically turn the wood 360 on the stopper. idea is sound, the practice too I believe...

Cheers
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Andres Sender
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Joined: 23 Mar 2007
Posts: 275
Location: N. CA

PostPosted: Fri Oct 30, 2009 8:34 pm    Post subject: Reply with quote

The only reasons to use a machine for the flats would be speed, accuracy, or fear of hand tools. Since you're not mass-producing you can't improve your speed by setting up a machine.

For accuracy or avoiding use of hand tools, I'm not sure there's any point in setting up a machine, because in my experience you simply can't make a decent bow without developing your eyes and skills so you can see how things are going and execute correct and clean work. You can't do it all by measurement and jigs.

If your goal is to get into this on anything like a professional level then I would encourage you to get some training, such as as Lynn Hannings' summer workshop in Southern California run by Jim Brown (alongside the Michael Darnton violin making workshop).

The hole through the spindle is something most metal lathes have but you have to look at the specifications for any lathe you intend to buy. Look at the 'spindle bore' size. A few smaller ones do not have a through hole there.

As far as putting flats on an already-rounded stick, are you sure this is even still possible? Who rounded the stick? Is it already at final dimensions? If so, cutting flats will ruin it by reducing the dimensions significantly.

If there is still enough wood then this can easily be done with a file. If you are unsure about getting the angles right, set up some sort of visual aid or jig. This is the sort of thinking you must be able to do if you are going to have at this on your own.
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Janito
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Joined: 08 Oct 2007
Posts: 114
Location: USA

PostPosted: Sat Oct 31, 2009 8:45 am    Post subject: Reply with quote

Centering the screw and having it parallel to the shaft is critical for the frog to work well later. That is why many makers establish perfect square facets at that end (relative to the head). It is then easy to make the exact centre.

A woodworking lathe is too crude for this work, and a metal lathe is used. This does not have to be large because the bow stick does not need to go through a hollow chuck - it can be mounted in a vice on the cross-slide horizontally (relative to drill bit). Then the drill bit can be driven by the chuck at the motor end. Exact alignment is essential.

Once the hole is drilled, an old screw and button can be inserted to provide the reference angles for planing with a very sharp small plane.

If it is great wood, I would show it to a good bowmaker and get advice on the process. You may be able to do this by email with photos and exact dimensions.
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Ed Shillitoe
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Joined: 23 Mar 2007
Posts: 110
Location: Syracuse NY

PostPosted: Sat Oct 31, 2009 8:18 pm    Post subject: Reply with quote

Hi Jokorum:

I agree with Andres that you really should contact Lynn Hannings and sign up for her classes in the summer. As well as the one in California she - and George Rubino - have classes in New Hampshire for a week at a time. Not only do you learn a lot from the teachers at these classes but you get to know a lot of other bowmakers as well.

Try to get a copy of the book Violin Bow Making by John Bolander, which illustrates every step of the French method of making bows. Its long out of print but maybe you could locate one. If you prefer to use lathes then get a copy of the Journal of the Violin Society of America, Nov 2002, vol 18 number 3. It has an article by Tim Baker showing all the steps of the Hill method.

Where are you located? Try visiting some bowmakers to show them your progress - personal help is better than a book.

Good luck!

Ed
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jokorum
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Joined: 27 Oct 2009
Posts: 8

PostPosted: Thu Nov 05, 2009 7:05 am    Post subject: Reply with quote

Thanks guys.... some helpful replies!

sadly I am in Europe and there are not so many bow makers readily open enough to pass on their secrets here or even help. Lived in Spain for 10 years working and the Czech Republic for 5 and family lives in France, but no open minded bow makers, unless you can already make and then you might be of some use to them..different continent sadly!

some basic info to put the old school makers at a possible relax (ey Andres!) ... just joking!

the circular sticks where rounded buy the bow maker I was given the blanks from... that was as helpful as he got. the sticks are 11mm on the diameter and are easily squared down to 8.5mm...just like you boys and girls do with your square stock...see how we aren't that much different!

then, I can put in the other 4 faces of the octagonal facets and we are all happy.

My actual question was simply designed for someone out there with all the skills to just throw in some useful info about lathe working.... I know that pro makers do use lathes on button and screw forming, nipple cutting and screw hole cutting.

Some of you very famous (modern) bow makers use the lathe to quickly cut in the octagonal on your square sticks at the frog end (which is the only bit I was curious about) and simply bring the stick into approximate dimensions and this way gives a certainty of exact octogonal cutting for the 10cm (and only 10cm) of the butt end of the stick for where the frog will sit. This meaning that with the planes (small or big and obviously sharp) you can then bring down the facets fractionally to fit the 3 faces of the frog.

So...do I enlighten you as to why I asked such a straight forward question? hope so... I am all for the old ways of making and luckily we also have a bit of good technology to help us with bettering a few things, so I thought I would ask especially being a child of the 20th Century... never mind!

Thanks again to all of you for your replies...

I have found out myself how to do what I initially asked....so if anybody is at all interested in learning how to quickly cut the basic octagonal in only 10mm of the bow at the frog end to start the process with good clean faces and exact positioning, just let me know and I will detail it as I was given it....

Take care
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jokorum
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Joined: 27 Oct 2009
Posts: 8

PostPosted: Thu Nov 05, 2009 7:11 am    Post subject: Reply with quote

should have read ..in only 10cm of the bow ..sorry . typing error!
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