Here is a list of all the postings Clive Foster has made in our forums. Click on a thread name to jump to the thread.
|Thread: Denford starturn 4 lathe|
The Starturn was a small, and now seriously obsolete, CNC lathe made for educational use. Nominally 140 mm / 7 inch swing by 200 mm / 8" between centres. By the time you have a chuck on the realistic work envelope is pretty small. Especially if you want to drill holes.
Constructional standards are good, the hardware solid and its accurate. Biggest issue is software and drives. Standard software is limited and obsolete. BBC B and MSDos versions only I believe. Folk do convert them to Mach 3 and Linux and claim good results but its not a simple bolt on job unless you buy a complete turnkey kit. As ever technically savvy folk can do clever things cheaply but normal mortals find it takes longer and costs more.
Biggest issue with these small, obsolete, CNC machines is that the cost of modernising and upgrading is pretty much the same for all of them. So you get much more bang for your buck if you go for a larger machine like the like its big brother Orac.
Although the Starturn was an excellent teaching machine in its day odds are you will find it far too limiting for anything beyond the smallest work. That said I did briefly cross paths with a guy who got "several" for "£ almost nothing" and put them to work making stainless steel bits for the piercing community (yuk!). Allegedly he did quite well for a while then sailed too close to the wind tax wise with the usual results. So it may well be suitable for your small brass fittings.
|Thread: Lead Screws|
Whatever you do you will need to support the screw where it passes over the bed. You need a clean accurate straight cut on the thread so its important to ensure that there is no way the job can climb over the cutter or waggle out of the way.
Were I to do the job I'd make up a support along the lines of the device shown by ega to hold the far, tailstock, end and make up an extra deep L block for my travelling steady to ensure that the cut is properly controlled. My Smart & Brown 1024 uses an L shape bronze block rather than the usual fingers for its travelling steady so its easy to make an extra deep one that won't run into trouble as the coarse leadscrew thread runs over (inevitably narrow) fingers.
I'd use a collet rather than a chuck to hold it and fit a bush in the back end of the collet tube to ensure no wiggles. I modified my collet tube to take interchangeable bushes of that ilk to do the job normally entrusted to a spider. Worked out well for me in damping out wiggles when working on relatively slender rods. Means I have to make a bush for each size rather than simply adjust a spider. But I reckon a simple running fit on a inch or so of nylon bush gives pretty equivalent support to a nipped up spider and I don't have to loosen the spider to push the bar in further for the next piece.
If you make up something like the excellent device shown by ega and arrange it to be dead on centre at the headstock end it will still be on centre wherever it is placed on the bed. (Assuming the lathe is in good order and properly aligned of course.) So you can work on whatever length be convenient.
There are a multitude of ways to make such a device. I'd probably arrange for the support bush carrier to have a modicum of adjustment accepting the slight reduction in rigidity as compared to a monolithic approach. The important thing is that the screw be well supported on centre-line and exactly parallel to the bed. Standard steady fingers are generally too narrow for this sort of job and the faces are rarely exactly parallel to the bed. Close but not dead nuts.
If you do make such a steady device put some thought into designing for versatility so it can be used for other jobs where the standard steady isn't ideal.
Edited By Clive Foster on 20/02/2019 17:18:23
Further to what Bazyle says its important that you do all the thinning on the same side flanks of the threads. Not too tricky if you can do the whole thing in one set up but if working in sections you do need to keep your brain engaged.
A classic "No way will I cock up something that simple!" trap.
Worst thing when re-furbishing a worn screw is that the master, thinnest, thread which all the rest have to be matched to is in the middle. If doing in sections you need a relatively long, nicely fitting bush, to support the hanging end. An ordinary fixed steady isn't enough. I'd be thinking in terms of a solid bush a couple of inches or so long made a close running fit on the screw and held in a solid support bolted to the lathe bed. Although a special support sounds more work than simply setting up in a steady it isn't silly hard to make dead right if you have a between centres boring bar. Done well it gives you the option of working on a short length at a time to minimise deflection.
On a job like this where you want right, really right, a bit more trouble at set-up time is worthwhile effort. Hafta say I've often spent time setting up with general purpose kit to "good enough to do the job if I'm careful" standard when saying "stuff it, I'll make something proper" right at the outset wouldn't have taken much longer and allowed me to "just do it" without crossed fingers and toes.
I've always felt that it should be possible to make a thingy with an internal thread and adjustable cutter that could simply be spun along the thread trimming the unworn parts back to match the worn ones as it goes. Never got my head round how to ensure that all the trimming goes equally on the same side when running both ways from the middle though.
|Thread: Crabtree B15 3 phase Stop / Start switch|
Fundamentally a VFD is a stop / start box. It just uses magic smoke hidden inside electronic package thingies instead of nice obvious contacts driven by a solenoid and has all sorts of other clever stuff inside too. (We'll not mention a manual that is not only large enough to be a serious drop hazard if picked up when not wearing hard toes boots but also a major threat to the sanity of any normal person trying to read it. Such are not normally considered advantages.)
Indeed the Eaton DE1 series VFD boxes are actually sold as a substitute for ordinary start stop boxes as being a simple way to get the usual VFD advantages of soft start and, if needed, speed setting. They require only the addition of simple switch controls to do basic motor stop / start, forward / reverse and, if needed, two speed duties. The internal parameters are preset to work fine on ordinary motor duties. Its claimed that any ordinary electrician can fit them with no special training. No display or buttons so they get hidden inside a cabinet. However if you look at the manual you find they are actually a full on VFD having all the bells and whistles inside which can be set-up in the usual way if you buy the programming widget.
Best thing to do with your Crabtree box now its fixed is to wrap it up and store safely ready to be re-fitted if the machine ever has to go back onto full fat three phase.
|Thread: Modern equivellent idea's please|
As Bazyle says time was most folks didn't use a DoL starter box on hobby machines. Mostly due to the cost as they used to be expensive in real terms. As I remember things thirty or so years ago they were around £30 - £40 upwards.
However these days single phase DoL boxes can still be found for similar money, whilst boxed NVR switches seem to start at around £25. Naked NVR units can be found under £10 but by the time you've bought a box, cut a hole, drilled for cables, found some grommets and mounted it up .....
If you time it right on a certain auction site New Old Stock DoL boxes can be under £20. I'd not worry about having an overload unit if the price were right.
At that sort of price differential might as well go for the proper thing. Especially as some of the inexpensive NVR switch sets appear to be only single line switching. Found that out when I unbuttoned one that had become unreliable. Off a friends table saw so was just expecting it to be bunged up with dust.
Edited By Clive Foster on 14/02/2019 19:40:54
Bill has it.
DoL starter after the drum reverser switch so there is no possibility of things being inadvertently left live.
Motor looks small enough to run off a normal 13 amp socket. If you want a more permanent connection one of the heftier variety of switches used for cookers might be better.
Personally I like the more modern lever style disconnector / switch units for permanently wired things. Plastic body perhaps 1/3 rd size of your old metal box with a big red lever on the front so you can see if it's on or off from the other side of the shop. Padlock holes too so it can be locked off. The ones I buy are grey lid for single phase and yellow lid for three phase. Maybe £16 a pop.
Edited By Clive Foster on 14/02/2019 15:51:43
|Thread: Denford Viceroy 280 motor and inverter|
Newton Tesla have a good reputation for supplying plug and play equipment that just works.
DIY is rather less costly but for real savings you need to shop at the lower end of the market where its easy to slip up if you don't know exactly what you are doing. Mix and match from branded UK supplied goods might save 1/3 rd. John can clearly do much better.
The balance of saving money against the hassle of being your own technical integrator and support person can be hard to find. Even at 65 I'm still far too often penny wise £ foolish!
Do consider a 6 pole 950 rpm motor rather than the standard 4 pole 1440 rpm one if the cost difference is small. The extra low speed oomph means you will be able to do almost everything with the belts on a single mid range speed setting and probably never need (noisy) back gear. Easy to be far too impressed with top speed rather than what you actually use.
Especially if you have a vari-speed system and decide to revert to standard belts as Pete suggests above.
Edited By Clive Foster on 14/02/2019 10:43:50
|Thread: New coffee maker - disgusting taste!|
Time to get a Teasmade. Bound to be one in an attic near you.
|Thread: Filling defects in slideways|
As I recall it the one I used was a basic metal loaded filler. Either cast iron or steel in it.
Most likely the cheapest one that looked up for the job! Product range was a lot slimmer then too. Especially the ones Joe G. Public could actually get in small quantities.
The one thing I really remember was how incredibly stiff it was when trying to mix the hardener in before it started going off. I'm certain i wasted half of the first mix, two or three teaspoons worth sounds about right for the first batch. Down to about one afterwards. JB Weld is much much thinner in comparison.
Used one of the Devcon metal loaded fillers several times on cast iron some 25 years ago with eminently satisfactory results. Not a slideway unfortunately but a couple of the jobs were baseplates on which things were regularly slid around. As I recall matters there was no picking up or scuffing / scoring due to material being excessively soft.
I was advised that the trick was to avoid feathered edges and thin layers. Couple of jobs were drilling machine tables with the usual collection of "just started" holes. Following advice I drilled them deeper to leave a sharp cylindrical ring in the 1/16" to 2 mm deep range. Worked well once I'd got the knack of kneading the air out when filling. I know of folks who used JB Weld for similar jobs with less than permanent results. Couple or three years before first issue methinks. How much due to JB Weld being less suitable and how much due to simple clean and wipe in methods I know not.
I have seen suggestions that thin dowels, pins or similar in drilled holes be used as up-stands whnere the material is built up above the surface or run to an open edge. Presumably the idea is to reduce any leverage effects on the adhesive join. Peel being the achilles heel of all simple adhesive joins.
|Thread: Habegger DLZF tailstock|
Looks like Schaublin, from which the Habegger was derived, also have a similar fitment on the tailstock.
Back in the day such blind holes were used to hold small quantities of lubricant for centres. Often white lead. The white residue that came out when anointed with brake cleaner seems suggestive.
A loose dibber, basically a steel pin with a small round knob of suitably artistic (or not) shape on top, normally resided in the hole resady to transfer lubricant to the tailstock centre when needed.
Looking at the final picture in your post it appears there is indeed a typical form of knob showing above the top rim of the hole. The tailstocks on some of the machines on the Schaublin pages here :- **LINK** also have similar knobs showing.
|Thread: releasing tapers|
I suspect that vibrational effects are much more important in taper release (and initial gripping) than is generally recognised.
I recall the flywheel extractor for the engine on an Acto rotary mower we had maybe 40 years ago. A simple round steel bar, maybe 6 or 8 inches long and 3/4 - 1" ish diameter, screwed on the end of the crankshaft after the flywheel nut was removed. With an assistant applying upwards force by holding the flywheel on opposite sides a sharp rap with an ordinary hammer on the top end made the bar go "Riiing" and the flywheel jump off its taper just like that. No levers involved. Simply held up by hand. As the holder when we first tried youthful Clive was very surprised. So was Dad. So much that we put the thing back on. Verified that it was still totally immobile by conventional means including big pullers, large levers et al and tried again with identical ease. At the time I wondered if there was some magic length and frequency involved but these days I think pretty much any adequately high frequency of vibration would have done. Being a nut welded on a piece of bar the thing was hardly sophisticated!
Getting back to machine tapers I'm probably not the only guy to notice that a dead-blow hammer needs a lot more walloping to shift a taper than an ordinary steel one. Hardly surprising if vibration is involved as dead-blow hammers are all about creating a solid push to shift things with minimal vibration. These days I strangle a club hammer and hit the drawbar on my Bridgeport with a sharp twist of the wrist to release things. Surprised the heck out of a sometime toolmaker friend who was borrowing the machine when my way shifted a stuck R8 with a single rap when a couple of minutes of his efforts with my big dead blow had failed.
My take on the tang issue is that with decent tapers in the spindle and on the drill only a modest push is needed to hold things well enough to start drilling. With the tang stopping rotation any vibration during drilling will act to push the drill harder into the taper. Sufficiently so that it will stay put if cutting conditions cause it to try to pull out. Without the tang the drill will be free to rotate if vibration or pull-out loosens the taper. Once rotation starts its pretty much impossible to stop. I have actually seen this happen with a moderate size drill whose tang had been removed. Said drill had been seriously walloped into place with a hammer and copper block but to no avail.
It usually seems to me when removing a taper drill that its in a lot tighter than initial insertion force plus drilling force. Vibration working things tighter could be why.
|Thread: WHERE ARE THE SHAPER USERS ?|
Just looked at my manual. As the pawl lifting knob, used to disengage the auto-feed system, also works against the same spring and through the same bore maybe a flush through in situ with Plus Gas followed by re-oiling might free things up enough to get it working. Once its going decent oiling and regular exercise should keep it happy.
I avoid WD40 for this sort of thing as any success seems to be rather temporary due to its tendency to leave deposits behind which go gummy after a while.
A known issue with the Elliott.
System does depend on friction holding the ratchet wheel in place whilst the pawl retreats. Assuming mine is typical the factory spring is very weak, probably provides a force equivalent to the weight of the pawl at most. As ever crud builds up making the action stiffer so the system doesn't work as it should.
Cure is to clean things out so the pawl moves freely. Big difference with mine between as obtained in apparently well looked after condition and post cleaning. However mine was more likely to stick up so there was no attempt to feed rather than do the forward - backwards dance.
Edited By Clive Foster on 10/02/2019 15:18:56
|Thread: Every Tea Room needs a toaster topic...|
Like Hopper I have fond memories of scraped, de-charcoaled, toast when I were a lad. Sunday treat only in our household tho'.
Similar style of toaster to that in the picture, albeit a gold-bronze colour, and also allegedly capable of flipping the toast over automatically. Which I never knew it to do successfully. Getting the manual change-over moment and time per side just right for proper, evenly through crisped toast was an art form.
Figuring out the best setting on a modern pop up doesn't seem much easier.
|Thread: Very soft stretchy rubber grommets, where from?|
Tried the cut a normal grommet and superglue suggestion from Speedy Builder5. Worked for a while but after a year or three the glue came unglued. Not sure how long it actually lasted. Know it was fine after one year but noticed it was unstuck after three.
Probably do better with the special glue supplied with split CV joint gaiters and similar flexi-rubber under car duties.
When dealing with small bonding areas and less than rigid substances correct glue choice seems to be the secret of success. Trouble is the right glues seem to be expensive and / or hard to get. Even when they claim to be suitable for difficult materials the consumer, blister packed, versions don't seem to be anything like as effective as the real thing.
My success rate is something like 1 in 3 with ordinary consumer glues on difficult materials. 100% when I've been able to lay my hands on the right stuff.
|Thread: Ettco number 1 friction reversing tapping head|
Further to my previous post this thread **LINK** on another forum indicates that for all practical purposes the Pollard ones are the same as the Ettco ones.
I think the Ettco tapping heads were also sold under the Fred'k Pollard label. They certainly look the same in all the pictures I've seen.
I have the Pollard operation and service manual covering all models 200, 1, 2, 3, 4 & 5. Service information seems pretty comprehensive as to dismantling but doesn't tell you how to remove the chuck. However the cut-away parts list diagrams clearly show a taper mount. I have a Pollard No 2 retro-fitted with 3/8" capacity Jacobs chuck marked 31-02 2S taper.
Seems likely that the Pollard ones are Jacobs taper.
If appearances aren't deceiving the Ettco ones will be too.
PM me if you'd like a PDF copy of the Pollard manual.
Edited By Clive Foster on 04/02/2019 20:27:59
|Thread: Alternative to a QCTP?|
Looking at the Viceroy pages here :- **LINK** I see they used a Tee slotted top slide like SouthBend. So you could take the same approach as I did with my SouthBend by making complete tool post, Tee-nut, stud and handle sets. Simply releasing the handle by a half turn was allowed my assemblies to be easily slid in and out. Memory says I used M12 threads on the stud.
The bottom picture on the page linked to above shows a compact and rather nice two way post. The Viceroy top slide is nicely flat, unlike the smaller, mostly curvy, SouthBend one, and that tool post has a bit of space round it. You may well find there is sufficient room to arrange an effective, easy to use, location angle template / stop system so that tool posts of similar size can be swopped around and always slid back to the same position. Possibly a round skirt at the base of the tool post with a set of cut outs or drillings at suitable angles sliding up against a part circle stop with s pin or projection arranged to mate with the cut-outs or holes would work. Pin probably better as it could be removed when needing an unplanned angle.
My experience with the SouthBend was that the template / stop system was sound in principle but impossible to execute in a properly satisfactory manner on the Heavy 10. Hence the rotating stud concept.
A system like this is an ideal home for a Geo. H. Thomas boring bar system with eccentric height setting sleeve. With a bit of low cunning you can also squeeze in a rather larger, stiffer, boring bar than conventional tool posts can carry.
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