Member postings for Ignatz

Just my two-cents woth on thiz. But it seems to me that even if one had the benefit of some sort of 'follower cam' to move the cross slide in and out to match the curve of the knife handle (using a push style knurler) one would still obtain a rather 'iffy' knurl as the constant change in handle diameter would have the knurl pattern (regarding number of even points around the circumference of the handle) changing over the length of the handle, varying from even numbers of points through to bands where one would have 'extra bits' and back into areas of even numbers of points. I imagine a visual going in- and out of phase sort of thing. Same sort of chowdering as that series of banded knurls on the example knife handles.. but more smoothly obtained.

The gear file is now posted on Thingiverse.

Just follow this link: Myford 46-tooth gear at Thingiverse

Edited By Ignatz on 24/07/2022 21:59:36

I'm posting the gear file on Thingverse, but as a new user I'm informed by the system that my posting won't go live for 24 hours. When/if that happens successfully I'll post the link.

I would be glad to share the file with anyone who is interested.

I no longer have a personal web page. Is there a way to post that file on this forum?

Those of you who own Myford series 7 lathes will know that when confronted by odd screw threads a full range of change gears is the order of the day. However, some of the original series of change gears are no longer available, in particular, the 46-tooth change gear is no longer to be found. Without this particular gear one cannot cut either a 46 tpi or a 92 tpi screw thread.

Now let me be honest. I’m not really sure that I will ever need to cut either of these threads. But I somehow suspect that Murphy’s Law dictates that given enough time someone will ask me to cut one these threads for some odd bolt, shaft or stud that is needed for repair work.

Instead of burning up a lot of machining time to create this gear I chose for the cheap route and decided to try 3D-printing one of these gears in PLA plastic filament. I’m not the first to do this. There are various videos on Youtube of others who have done the same.

I opted to use the freeware program FreeCAD that has a built-in gear generator algorithm. The form I generated was passed into the Blender 3D software for inspection and cleanup and from there I wrote out a file in the .stl format which I sent to a friend of mine who has access to a 3D-printer. One day later he presented me with two copies of the gear.

The photos pretty much tell the rest of the story. The gear slid into place without any undo fettling. It meshed perfectly with the other metal gears in the train and (most important of all) didn’t fly to pieces when under power.

A test cut was made at 46 threads per inch. However, my thread gauge set can measure either 40 tpi or 48 tpi, but hasn’t provision for that elusive 46. So just to be sure, I held the points of a vernier caliper against the shaft and using a magnifier counted the threads for a measured distance along my work. Success!

So, now these plastic change gears will go into the drawer, there if I need them in the future.

Hope this inspires some of you.

Ran a quick test on the metal lathe with one of the cutters. Didn't bother doing any grinding, but simply took a few very light test cuts. Yeah, it worked and the carbide held up quite well, but they won't be useful as ordinary cutters without changing the geometry a bit.

However, I suddenly realized that what they ARE good for in this unaltered state is being used as gravers for things like the increments on machine dials, using the carriage, back and forth, as a poor man's shaper. I slapped one into the tool holder sideways and made some stopped graved lines in a bit of scrap steel. That worked a treat.

Interesting suggestions, guys. I guess I'll take one of these to the grinding wheel and then see if I can use it on the metal lathe. Should be an adventure.

A recent trip to the local flea market netted me a small grab bag of tool steel, lathe bits and... these carbide tipped cutters.

The question concerning the cutters pictured below: Can anyone think of what they might have originally been intended for?

These cutters look like they might be used on the metal lathe, but the shape seems slightly wrong for that in current condition. They have no manufacturing marks, but the brazing work looks quite good. They all have a cutting angle of between 84° and 90°. I'm thinking I could regrind them to a sharper angle on a green wheel and use them for thread cutting or such.

Any ideas?

Just another shoutout of thanks to all of you for the hints and suggestions. The spindle and cross slide adjustments have made a nice improvement in the lathe's performance.

Now that the spindle and cross slide have been seen to I also took the time to proceed with final leveling out of the lathe bed using the suggested method of cutting a test bar. A few tweaks to the bed screws brought that round right. I do note a bit of bed wear at the headstock end, but of course to be fair, this lathe is getting on 26 years of age and I'm by no means the first owner (second? third? fourth?). If I really want to drop some coin on this, that machine shop up in Holland does offer regrinding services, but I'm thinking that I'll first see how the lathe performs for me before taking any big (and doubtless expensive) decisions.

Martin,

I gave some attention to that feed screw collar, tightened it up as much as possible without totally locking up the works. The backlash in the cross slide feed screw advance is now reduced to something around 10° of rotation of the handle. Relative to the previous amount when I first started these adjustments this feels more or less like 'immediate' response and is something I can absolutely live with.

If I really wanted to go crazy, there is a conversion kit offered by Vintage Tools in the Netherlands that replaces the end plate with a new one that uses thrust bearings. But it might be a bit of overkill for me. Vintage Tools Conversion Kit

Thanks, Martin.

Yes, already figured out that part about winding the cross slide all the way in before tightening the end plate, but I will go back and double check the feedscrew collar. The backlash is already drastically reduced, but I don't mind trying to make it a bit better if at all possible.

Thanks guys!

I've just spent a quiet hour or so, following the advice (re)adjusting my Super 7.

It all seems to be 'sweetness and light'.

As an added bonus, this second time around while setting the gib on the cross slide I happened to notice that the screws retaining the cross slide feed nut were loose. Tightened those up and as you can guess this has definitely reduced the cross feed backlash. ( Me doin' a happy dance! )

Now that the warm weather has finally settled in I found time to give my new (old) Myford Super 7 a closer inspection. In doing so I realized that both the spindle as well as the cross slide needed some attention.

The main spindle seemed to ‘bottom out’ when subjected to end force as when tightening up a live center in the tailstock against the workpiece. As for the cross slide, it seemed just a bit too easy to move, suggesting that that the gib needed to be snugged up.

Now, in both cases the Myford Super 7 manual has fairly clear instructions as how to adjust both the main spindle clearance as well as the cross slide. I dutifully followed those instructions and seem to have obtained good results. Unfortunately, what seems to be missing from the manual are clear and definite measurements such that I do not think that I can reliably judge the end results of these procedures.

In the case of the main spindle, to quote from the manual:

“… Move the ball bearings and spindle back until the spindle cone contacts the tapered bush and will not rotate, i.e. to a condition of no clearance. Clearance can now be set by moving the spindle forward from this “solid” position by a ¼” rotation of the rim of the locking rings (i.e. 15 degrees). This provides a preliminary setting which may be varied according to running conditions.”

What does this mean in reality? How far would the spindle move forward away from the headstock from the no clearance position in order to provide the ideal space between spindle cone and bush for an appropriate oil film? And how would I know if I accidentally moved the spindle too far? Would this result in greater amounts of workpiece deflection away from the centerline when cutting? How should I measure this?

[ Just to note that following the adjustment that I have already made, the measured runout of the spindle both on the exterior and within the ground Morse taper of the spindle (not running and with no load) is at or very slightly less than 0.01mm (= 0.00039 inch) which seems OK. ]

A similar question presents itself relative to the issue of tightening up the gib on the cross slide. Here again I quote from the Myford manual:

“ ... remove the two screws securing the cross slide end bracket so that the cross slide itself can be pushed back and backwards and forwards across the saddle manually. The four cheese head screws in the top of the cross slide should be slackened off and then just nipped, and they should be in this condition whilst the necessary adjustments are made to the grub screws. “

Again, there is no quantification of what those 'adjustments' to the gib should be.  So just how loose or tight is actually correct?   Should I be trying to measure side play or something?

Any information or tips anyone can offer to these questions is richly appreciated.

Edited By Ignatz on 08/05/2022 14:52:54

The only way that I know of to prevent this from happening is to eliminate all of the free oxygen in the pain container. This can be done by injecting a non-reactive gas that would displace the air in the container. Logical choices would be carbon dioxide, nitrogen or argon. Having said that, I freely admit that doing this requires some sort of ready-to-go apparatus (at least a small gas flask, valve and tubing), taking up a bit of space and very likely costing more than the paint it saves... not worth the time or trouble unless dealing with lots of cans of paint all the time.

Another trick I have tried (but with limited success) is to fashion a sort of floating 'lid' of aluminum foil to sit on the surface of the leftover paint in the tin. One still gets a bit of a skinning, but only at the exposed edges of the aluminum foil. To reuse the paint, slice through the foil and dip the brush. Nevertheless, given enoigh time the paint still wants to go off, albeit more slowly.

Just a thought....

Considering how fine the thread count is, I'm wondering if this wasn't a special tap for something in the camera/optical field.

I've had more than one occasion where I needed to use some sort of wrench size that I did not possess.

in these cases I would trot off to the flea market and buy the nearest size I could find, either smaller or larger than required.

The usual routine is then to pop a carbide cutter in the mill and open up a smaller wrench...

...or with a larger wrench first lay a line TIG welding along one of the jaws to close it up a bit before milling to size.

All sorts of ways suggest themselves to make those special wrenches you just won't find.

Be creative.

I would suggest the video link below as a good introduction to possible uses of the pulse feature.

Testing TIG Welding Techniques

My TIG welder also has the pulse capability. As Andrew pointed out this is NOT a cold process, rather it is a way to control heat input.

Especially on thinner materials, with a continuous arc not only melts the metal to form the weld bead, but also can add so much heat into the surrounding metal that the entire piece burns through before one has successfully welded it.

The pulse process allows the operator to define the on-off welding current time such that only the required amount of heat is used. Usually, this just means a more controlled welded seam, without dumping unneeded additional heat into the surrounding area. And, yes, the process can be so slowed down to the point that it is, in effect, a sequence of 'tacks'.

Another benefit of the pulse process that I might mention is that used at higher frequencies the pulsating arc agitates the weld pool and encourages a better blending together of two edges of butted metal.

Of course the pulse process is only another 'tool' and one usually has to practice a bit to find the correct pulse settings (frequency, on-time, base current). Best to do this on some scrap before you tackle the actual work piece.

One other use that I have found for the pulse process is smoothing out the edges of extremely thin cut metal (such as stainless steel). For this I set the pulses at a somewhat slow rate (something like 2 to 5 pulses per second) and the welding amperage only sufficient to 'bead' the edge but not cause it to melt back. In this way, I can run the pulsed arc along the edge of the metal, the series of little beads forming a smooth, rounded off edge.

@ john fletcher, ... I used that PTFE tape on the oil gun connection. First cleaned all the oil off of the threads (both inner and outer) and then gave three tight wraps of the teflon tape after which I tightened up the connection with two pairs of pliers - using suitable amounts of cotton cloth between pliers and fittings to avoid damage to the parts in question.

The oil gun now works a treat. No more leaks from that joint between the brass pump and the steel extension.

Of course, I still get a splash of oil should I not make a perfect connection between nozzle and oil fitting on the lathe, but that's all part of the fun, right!?

Jason, ... I totally agree... and my rough backplates are probably much too long as pictured.