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: Any other bowmakers on here?|
As I've been on the forum since the start of the year, I thought it was about time I introduced myself. After having been working in IT for 23 years, I'd had quite enough and decided to indulge in my love of woodwork and making things by enrolling on what I considered the pinnacle of woodworking courses, making and repairing violins at the Newark School of Violin Making. I was part-time at first, but soon gave up the IT work and went full-time, completing the course in 2016.
Since then, I have been in touch with a retiring maker of violin bows based in Bristol. As I had done some work making and re-hairing bows since the course, I decided to purchase tools and materials from him prior to his retirement.
Bow-making is a very different discipline to making instruments, being a combination of engineering, jewellery and of course some woodwork. I could also throw in 'hairdressing', as the bow is really just a way of tensioning a thin flat ribbon of hair from the tail of a white horse.
Having been woodturning since I was a lad, and being very interested in the engineering aspects of making bows I purchased a Myford Super 7 lathe at the beginning of 2019. Since then I've spent most of my time learning metal turning, milling and toolmaking. So far, I've made Howard Hall's mini surface gauge and I'm currently in the middle of making the Hemingway sensitive knurling tool (based on the Marlco). For a newbie with only a lathe and a pillar drill, I'm not finding it easy, but I'm really enjoying the challenge.
Once I've finished the knurling tool (and probably several other projects including tailstock die-holders, etc.), I'll be moving back onto making bows. I intend to use the lathe to drill sticks, mill bow frogs (the part that slides on the stick to tension the hair), turn down pearl eyes and make adjusters (the ornamental ends of the screws used to apply the tension), as well as making many of the specialised tools.
For interest, I've included a picture of the 'engineered' parts of a bow below:
My avatar is the head of a violin bow. It was made by one of the finest French makers, Pierre Simon, during the early 19th century.
|Thread: Myford Vice for Vertical Slide|
I like the idea of the round nosed cutter, which I assume would 'spread out' any stresses in the corner. I also like the idea of the replaceable jaws, though it would reduce the capacity of the vice. Does anyone have any photos of their own modified Myford vice? Or perhaps a better alternative vice that fits the standard-sized milling stand.
I also have a Groz 3-way swivelling vice, something like this:
However, the centres for the bolt holes won't fit the standard milling stand. Does anyone have any thoughts on this? Is it simply too big to be used for milling on the Myford?
Apologies to all, I had obviously misunderstood the word 'arris'. Next time I'll stop trying to be clever and use common English!
The photo below shows the radius at the base of the fixed jaw. I have been using packing, though I have no accurate parallels, so I expect the accuracy of the setup will be compromised. Would it be a good idea to run a narrow slitting saw at 45deg into the corner to remove the radiused section? Using a radius gauge, I found that the radius at base of the jaw is about 1/16". I'm surprised that Myford did not machine this truly square, or is this a common occurrence on machine vices?
I have an original Myford small vice for the vertical milling slide. I wondered whether anyone else has had a problem with the fact that the base of the fixed jaw has not been machined square but instead has an arris that pushes any square-edged material out of the vice slightly when the jaws are tightened. I was hoping to use the base of the vice as a reference surface. Am I wrong to expect to be able to do this?
Does anyone have an easy solution to this? Am I missing something?
|Thread: Myford Super 7 and ER40 collet chuck|
Thanks for the advice. ER40 chuck ordered today.
I am looking to purchase an ER chuck, set of collets and backplate from ArcEuro for use on my Myford Super 7. However, as neither Myford nor RDG offer anything above ER32 specifically for the Super 7 I wondered whether the ER40 is deemed too unwieldy. Does anyone have any views on this?
Specifically, I am wondering whether the benefit of being able to hold, say, 1" material accurately in the ER40 chuck, as opposed to the more limited (3/4" capacity of the ER32 chuck, would outweigh the drawback of the additional chuck size (and of course the higher cost) of an ER40 system. I realise that stock at these diameters would not be able to pass into the lathe spindle's bore.
The only ER system I currently own is an ER20 MT chuck that I originally purchased for my woodworking lathe.
|Thread: Myford Dividing Head and Raising Block|
I have a Super 7 and have recently purchased a dividing head. I plan to use it for milling octagons using the non-swivelling vertical milling slide (probably overkill to use a dividing head, but hey!). I therefore have the milling head axis at right angles to the lathe axis. However, I'm finding that the cross slide needs to be wound out a long way to bring the milling cutter anywhere near the workpiece, held in an ER20 collet in the dividing head, as the vertical milling slide does not fit the T-slot in front of the top-slide hold.
So... my question is, do I need to purchase the (expensive) milling slide raising block, or is there another way?
|Thread: Hexagonal Socket Drive|
Great - thanks chaps.
I have a ratchet wrench and brace with a 7/16" hexagonal drive, instead of the (more modern I assume) square drive. Does anyone still use these? Anyone know what they were for and what vintage they are and, more to the point, whether they're worth anything to anyone?
The ratchet wrench is a Britool 2073.
Edited By Mike Donnerstag on 06/06/2019 12:42:45
|Thread: Myford Super 7 Bed for Power Cross Feed|
Quick question: I have an early 80s Super 7 with gearbox and power cross-feed. I am looking to replace my worn bed and wondered what differentiates the various beds. Specifically, what makes a bed a power cross-feed bed?
|Thread: Myford Clutch Lever fouls the Belt Cover|
I probably should have mentioned my reason for asking. The paint on the belt cover has worn off due to the clutch lever fouling it. Obviously this is only cosmetic, but as my lathe has had a hard life I was wondering if this was just another part of the lathe that is in need of adjustment.
Just as an aside, I still have a single phase (no-variable speed) motor, and use the clutch all the time instead of stopping and starting the motor all the time. I assume that those that have 3-phase and a VFD would leave the drive from the motor engaged all the time, hence the lever being to the left, potentially fouling the belt cover. Am I right?
Hmmm... that sounds as if it is working as designed then. Mine is a green Super 7 from the early eighties.
Many thanks to you all,
Should the clutch lever on a Myford Super 7 foul the main belt cover, or is it that mine requires adjustment? When the clutch is disengaged (lever to the left), the belt cover hits the lever ball end if the cover is lifted or lowered.
|Thread: Myford Super 7 Bed Wear|
Chris: No, the damage is only to the front edge of the bed.
Yep, first thing I did before using the lathe was give it a thorough clean and oil, especially under the saddle. The lathe had no felt wiper or plate when I bought it, so this was also fitted after cleaning and oiling.
That was my guess too, Russ. Perhaps even a grinding fixture for grinding tool bits? It looks almost as if sparks have eaten away the metal over time. Is that possible?
Many thanks to you all for your help. The lathe was bought at a relatively low price for a powered cross slide model with a gearbox and being my first metal lathe (I've done plenty of woodturning) it was a risk I took to get me started in metal turning and lathe milling. I'll adjust the shimming of the saddle over the next few days as I assume this may help with milling..
I have uploaded two photos of my Super 7 bed, which show some rather nasty wear near to the headstock. My question is, does anyone know what this might have been caused by?
I had seen several Super 7's before buying this lathe, and they had significant wear. I have nipped up the saddle gibs with the saddle near the headstock and the carriage only starts to tighten when moved to within 4" of the end of the bed, and even then it is still movable. Would you consider this average wear?
The saddle has no movement when I try to lift it at the rear, so the shims seem to be doing their job. However, there is movement when I lift the saddle at the front, even at the very end of the bed. Is this normal? Do you think I should fit additional shims to remove this movement?
Once again, many thanks in advance,
|Thread: Myford S7 Power Cross Feed Apron Adjustments|
I have a Super 7 with power cross feed saddle. When I received the lathe, the half nut lever was stiff. I slackened the gib screws to ensure the gib moves freely, though the half nut lever only eases off when I loosen the two large screws at the front (LA8 in the manual). Can anyone tell me whether these should be tight and whether I am perhaps tightening things in the wrong order? I have had the saddle off in the past and everything is clean and oiled.
I also wondered what the socket grub screw in the side does (LA58) and whether this should be tight.
The only adjustment given in the manual is for the 2BA cap screw (LA6). I have to admit that I am similarly confused about how this is adjusted. The manual states, "...adjust the setting … until it is in contact with the under side of the upper half of the leadscrew nut". How do I determine this when it can't be seen?
Any information gratefully received.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.