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Member postings for Mike Donnerstag

Here is a list of all the postings Mike Donnerstag has made in our forums. Click on a thread name to jump to the thread.

Thread: Myford ML7 tailstock bore, and threading the barrel to fit a chuck
15/07/2019 13:27:56

Thinking about it, I probably should have renamed this post 'Myford Hollow Tailstock Drilling Fixture'.

15/07/2019 13:27:29

It's a good idea, in fact I have an ER40 collet chuck with a full set of collets, however I would prefer the self-centring four jaw chuck that I also have because it grips on the flats rather than the corners of the octagon. A split nylon sleeve with an octagon (not hex) centre seems like a solution, though there are so many variations on bow stick size that I would have to make several.

15/07/2019 10:48:06

Bandersnatch: I can't say I'm seriously rich, though the £100-odd ML7 headstocks seem to be going for on eBay looks reasonable if it's a solution to the stick-drilling problem.

peak4: This was my original idea, though I expect lining everything up would take some time, whereas a tailstock setup would simply slide on and off and I expect its alignment with the spindle axis would be more reliable.

A commercial tool, which is basically only a self-centring vice and drill guides, costs £600-ish and has to be imported from America. It's called the Bow Badger:

And below, in use:

I'm sure there is a better and much cheaper way to do this!

Edited By Mike Donnerstag on 15/07/2019 10:50:04

Thread: Any other bowmakers on here?
15/07/2019 10:35:35

I have to admit that I have little idea of how carbon fibre bows are manufactured - it doesn't seem like healthy or enjoyable work, nor does it produce a traditional bow that professionals are willing to pay good money for. I believe solid carbon fibre and fibreglass bows are best suited to mass production, rather than the small batches and one-offs that I will be making.

14/07/2019 15:25:44

Mark Smith 20: It's good to find someone who knows a bit about bows. What is your interest? Do you have any tips on the engineering side of bowmaking?

14/07/2019 14:36:14

Cornish Jack (Bill): Many thanks, but I have a stock of pre-formed panels that are shaped with the camber of a bow. I just need to get them cut by water-jet.

Thanks anyway,


Thread: Myford ML7 tailstock bore, and threading the barrel to fit a chuck
14/07/2019 12:20:38

Interesting, though I like the idea of using a self-centring four-jaw chuck to grip the octagon concentrically (at least within a few thou). Bruising the wood shouldn't be too much of a problem as it shouldn't need to be held tight enough to bruise, and Pernambuco wood is very hard and dense.

The reason I like the idea of the tailstock is that the alignment with the headstock can be easily set and relied upon.

14/07/2019 11:55:19

Also, do you know the length of the standard ML7 tailstock barrel?

14/07/2019 11:54:55

Brian: I like that idea. I assume that, to keep the whole drilling setup easy to attach and remove from the lathe, that it would be best to get a second tailstock casting, i.e. the hollow ML7 one? Or, would the Super 7 tailstock casting work?

Also, do you know the thread of the barrel? Is it multi-start?

Thread: Any other bowmakers on here?
14/07/2019 11:13:00

mark smith 20: Very true, though it could really be made from something more hardwearing for practical purposes. I see a lot of old bows with lovely figured pearl slides that have been almost eaten through from the acidic sweat of the player's fingers.

Thread: Myford ML7 tailstock bore, and threading the barrel to fit a chuck
14/07/2019 11:10:42

Great - that bore will definitely work for bows up to cello size, and probably most bass bows.

Looking at the Super 7 headstock barrel, it seems to be big enough to accept the headstock thread, but I'd need to fit a separate 'register' so that a chuck can be threaded on.

Once again, has anyone done this? I know it is possible to buy MT2 spindles with the headstock thread, but I would need to use the bore of the tailstock, so using the taper doesn't get me anywhere.

Thread: Myford Vice for Vertical Slide
14/07/2019 11:00:52

Michael Gilligan: Mine has the engraving of the Myford name and part number too.

Jeff Dayman: The fixed jaw has no holes drilled at all, though there's nothing to stop me from drilling it for fitting false jaws, though I'm worried a little about the resulting accuracy.

Thread: Myford ML7 tailstock bore, and threading the barrel to fit a chuck
14/07/2019 10:55:31

I have a Myford Super 7 with the Super 7 tailstock and understand that the ML7 tailstock fits on the Super 7 bed.

I wondered whether anyone can tell me the bore size for an ML7 tailstock as I'm looking into the possibility of gripping long 'bar stock' (actually violin bows) for drilling the ends. As the bow has a gentle bend, it must be held still while drilled to avoid damage.

Also, to allow this to happen, there would need to be a thread and register on the tailstock barrel to fit a chuck, similar to the headstock spindle . Has anyone ever done this? Is it even possible, as in, is there enough metal in the tailstock barrel?

Thread: Any other bowmakers on here?
14/07/2019 10:39:52

AdrianR and Michael Gilligan: You may well be right about stallion hair being longer, and perhaps slightly stronger. I'm hoping to visit Michael Sowden (the horse hair supplier) in Beverley sometime soon, so I should find out more.

Mick B1: There are very good carbon fibre bows, and probably some reasonable fibreglass bows too, that would play basic bow strokes perfectly well. However, for a professional who is looking for the right weight, balance, tension and resonance for advanced strokes such as staccato, spiccato, sautillé, etc., I understand that nothing is as good as Pernambuco wood. I have the equipment to inlay pre-formed strips of carbon fibre into a finished bow made from lower grade Pernambuco, resulting in a bow that should be getting close to a good Pernambuco bow, possibly better. I have prototypes, but I've yet to receive feedback from a professional player.

Thread: Myford Vice for Vertical Slide
13/07/2019 20:29:19

That looks far more like what I would expect of a milling vice! Comparing the photos also serves to illustrate that I need better lighting in my workshop!!

Thread: Any other bowmakers on here?
13/07/2019 19:28:21

Barnaby: I reckon I'm too much of a pacifist for longbows, though musical instrument bows did evolve from hunting bows.

13/07/2019 18:59:21

Michael Gilligan: It is thought that stallion hair is the 'best' hair for violin bows, though I've only used Sowden's mare's hair, and I've had no complaints. It's understood that mare's tail hair is stained towards the lower end because they pee on their tail! I believe that is why stallion hair is preferred. However, once rosin is applied, the powdery residue of the rosin makes the hair white again.

Horses for courses!

13/07/2019 18:45:18

Martin: I had to look up IRRC, but couldn't find what that means. In my opinion and the opinions of the professional musicians I've dealt with, Pernambuco wood is not only the best but really the only material that a bow should be made from. Actually, £150 for a silver-mounted bow is very cheap. A hand-made bow would normally start at ten times that, and much more by a maker with a reputation.

Do you still have the violin?

13/07/2019 18:38:04

Many thanks chaps!

Neil: The pearl inlays are only cosmetic, they serve no practical purpose, though it could be argued that the pearl eye at the end of the button hides the end of the screw, as the hole for the screw is normally drilled through the ebony.

Just for interest, often the shell of the abalone (a type of mussel) from different regions is used instead of mother of pearl as it has more colours and figure. The above part would be made from ebony (the body), stirling silver or rose gold (rings), shell (eye), brass or bronze (the 'brass-eye' ), and steel, stainless steel or titanium for the screw, with pins securing the silver rings made from 1mm silver wire.

As for the bow stick that has lost its shape, or what is known as camber, it can be re-cambered with dry heat but it is a skilled process and one that always carries a degree of risk. A pin-knot or shake in the wrong place can be enough to weaken that part of the stick to cause it to split or break. A broken stick can sometimes be repaired, but it affects the value of the bow considerably. While I would be happy to re-camber a bow of little value, I wouldn't want to re-camber a valuable bow.

Edited By Mike Donnerstag on 13/07/2019 18:51:27

Edited By Mike Donnerstag on 13/07/2019 18:51:49

Thread: Myford Vice for Vertical Slide
13/07/2019 15:25:44

Alan Vos: You're right - I hadn't noticed that! I will find or make more appropriate washers for the vice. Many thanks.

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