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Member postings for Clive Foster

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: Lathe lighting
06/12/2019 10:04:43

If using a mag base for flexible mounting put a small, thinnish, plastic bag round the mag base and tie the neck to intercept any ferrous swarf. Periodically remove the whole thing and peel the bag off with the magnet off to remove the swarf encrustation without tears. With care you can even re-use the bag a few times. The thicker varieties of cling film also work but one time only and need care in removal because swarf can cut through and stay behind. Naturally its the really sharp bit!

Various breeds of inexpensive flexi stalk desk lamps that will work well when transplanted from the weighted foot to the mag base. The IKEA versions are said to be good although not the cheapest. They do one type with a big bulldog clip type attachment which might do well on the splashguard. I got a bunch from LiDL but have yet to use them. In retrospect a battery powered lamp would be better. No trailing wire to worry about.

My main lights are folding rigid arm types with Edison Screw LED bulbs fitted after changing the holders. The one on the Smart & Brown, a relatively short machine, is mounted on the wall above and behind the tailstock. The P&W is longer so its fixed to the middle of the spashguard. Both give decent coverage of the work area. Professional standard lights originally sourced from RS (but at surplus prices) so I'm unworried by 240 volt mains power. Bases are fixed anyway and I don't use the built in switches.

I also have area lights under the shelf above.

Much to be said for wiring the light direct to the main lathe power switch to act as a power on indicator. When the lights on the lathe can run. If nowt else it will remind you to switch the thing off when you go in for supper.

Clive

Thread: Breaking bandsaw blades
04/12/2019 10:59:17

ega

As Brian said anything you can do to give the blade an easier track will help. Adjusting the guides as close as possible to the work was always my normal practice. On my saw the guideways were a little out of parallel and out of plane adding yet more confusion to the mix.

Brians wire would probably have saved me a decade of on and off futzing around getting things a bit better every time I got fed up enough. At one point I seriously considered re-machining the wheels and the whole bow assembly.

The bigger version is much less trouble, although still not up to proper industrial saw reliability which Is probably indicative that our small ones push the design envelope a bit too far down.

I wonder if switching to 3/8" blades would help. My experience is that overstress breaks always begin with a notch from the back at close to 90°. The break then runs off at whatever angle was weakest. Which suggests serious stress concentrations at the back. A 3/8" blade will be outright more flexible and won't have the bit that really suffers.

Clive

03/12/2019 19:27:51

Oh dear, Neil is being pseudo provocative again.

Both under-tensioning and over-tensioning blades leads to premature breakage. Right tensioning is needed for longest life.

Depends on the design of the saw as to which is worst. Many saws won't drive well enough to break the blade if seriously under-tensioned.

The common small horizontal / vertical saw will quite happily break blades when under-tensioned because the blade has to have more than the, objectively, correct tension to work well. So under-tensioning enough to let it judder around, partially jam et al will still drive it well enough to break the blade. Especially if too fine a tooth count is used on larger jobs making the thing very prone to jam up due to filled blade gullets half way through the cut line.

The brutal blade twist between wheel and guide really doesn't help nor does the seriously sketchy blade downfeed pressure controls.

Superb value for money though they are these saws are a mass of contradictions and compromises that need carefully informed use and setting up to get the best out of. Which unfortunately they don' t get. Perfect performance out of the box is theoretically possible but who in the intended (guy or gal in a shed) market sector can afford it!

Clive

Edited By Clive Foster on 03/12/2019 19:28:11

03/12/2019 17:21:06

Brian

Thank you very much for explaining the wire method of verifying guide and wheel alignment.

From experience with my saw, admittedly an earlier one and less well made than most current suppliers offer, two further points are worth checking.

Firstly wheel flange thickness and truth relative to the surface the blade runs on. The flanges on mine are neither constant thickness nor properly true to the main wheel circumference. The combination wobble makes it remarkably difficult to see what is actually going on. Mine needs a small, but rotationally variable, gap between the back of the blade and the flange to ensure that a combined high spot doesn't launch the blade out of line once pre revolution.

Secondly all the clearances on mine are very slack allowing things to move around as tension is applied to the blade so best alignment can be lost during the tensioning process. Worse it doesn't always settle back properly after changing the blade so alignment can be lost during initial running. Fortunately such loss of alignment is fairly easy to hear and see if you make a point of looking out for it. Frustrating but fixable.

I really should bite the bullet and re-machine the thing but I use it so rarely these days as I have a Rapidor power hacksaw for stock cutting whilst the Startrite vertical handles most other things, that it hardly seems worth the effort.

Clive

03/12/2019 13:25:58

Ians comment about over tensioning reminds me that my old style, UK built, 14" throat Startrite vertical bandsaw requires a noticeably lower tension on 1/2" blades than the Alpine 6" capacity horizontal / vertical saw. The Startrite uses a spring to apply tension via a big knob on a screw with a nifty viewing window showing the size of blade that tension is appropriate for. Much nicer than the "heave it up and hope" system used on the Alpine.

Was told that the small horizontal vertical saws had to have the blade over-tensioned to work correctly due to the combination of small, relatively closely spaced wheels and savage twist between wheel and guide. Allegedly you want wheel diameters approaching 30 times blade size on centre spacing approaching 45 to 50 times blade size if a smallish two wheel saw its to work really well. I imagine it all gets easier once you have enough wheel size and spacing so larger saws have different rules.

Wish I'd known about Brians wire trick 30 odd years back. Would have made setting mine up so much easier. As I recall matters the killer wit mine was one wheel twisting a bit when fully tensioned so the flange kicked the blade out of line as it came off the wheel. Which took a deal of sorting to generate appropriate clearances and blade support once I'd figured the problem.

Clive

Edited By Clive Foster on 03/12/2019 13:26:34

02/12/2019 18:13:57

Something very wrong going on there. A professionally made blade shouldn't break at the join like that until its very old and well past its use by date.

I've had them go in a similar manner, including the jump, when I've cocked up the joining using the welder on my Startrite saw but that was pure operator error. Either poor welding technique or not getting the blade straight so there is a step on the back at the join. I rarely have problems when making the 112" blades for my Startrite vertical saw but my old Alpine horizonta/ / vertical is much more demanding.

Best guess is that the blade tracking is well out with the balde not sitting properly back against the rear bearing and / or not properly held parallel between the the side bearings.

The common small horizontal / vertical bandsaws are notoriously hard on the blades due to the small wheels, short wheel centres and rapid twist betwixt wheel and guide. Being made to sell at an economic price the various alignments and adjustment arrangements are not as well controlled as one would ideally like.

Best to make sure that the blade is sitting true on the rear roller and properly held between the side rollers with minimal tension applied. Then make sure that the blade is tracking ture on the main wheels without touching any flanges. (The drive on my big Startrite can be disconnected allowing the wheels to be spun by hand which makes life much easier. No flanges on the wheels either but setting up from scratch isn't trivial.) Once the balde is running true in its natural position you can then carefully crank the tension up re-adjusting as needed to keep the blade running free.

Being one of the early imports my Alpine moved all over the place as tension was applied. I had to run it with the cover open to see what was going on.

Clive

Thread: Kerry 1124 lathe - some healing required
02/12/2019 16:45:51

Agree with Pete about boring the adjuster hole a touch deeper to give a clean seat for the screw. However I'd clean up the end of the gib and carefully weld an extension on to take the adjuster screw engagement slot.

Done right by welding both sides with suitably low currents and a bit of peening whilst it cools to counteract the bending stresses the extension ends up essentially straight. Dont try to straighten it if it is a bit wonky. Excellent chance of distorting the gib.

Just carefully file the extension until the shape is close enough that it fits in without binding. The area covered by the extension contributes vey little to overall stiifness so a thou or three clearance just there matters little.

I'd probably attack the main casting with the welder too and work it back to the right shape. But I have form for doing such. Realistically a bit of metal loaded filler to hide the distress is a more sane way of dealing with things.

Clive

Thread: 1P 240V Lafert Motor In Colchester Student Lathe - Wiring Help
27/11/2019 19:47:35

Martin

Two capacitors suggest that this is a capacitor start - capacitor run motor. The skinny wires will be to the start coil.

If so the relay will be a voltage / potential operated type. The blue box may well be something to do with trimming the relay coil response curve for more positive behaviour.

Clearly a good and rather sophisticated motor. We need to find someone who knows exactly what it is and how to wire it up so the control gear works correctly. Perhaps one of the guys on the American "Practical Machinist" site would know. If you want I could ask.

That said the last time I had a motor designed to work with an external start control relay through my hands I simply wired an extra button and contactor into the control box to handle the start capacitor and simply held the button down until it came up to speed. Crude but effective. When you have just intercepted a high quality Brook 2 HP single phase motor that "won't start" on its way to the bin a certain amount of improvisation is in order.

As your s is on a lathe with a clutch and will always start up off load a simple time delay really would work well enough. A couple of seconds with the start capacitor in circuit should get it going just fine.

Clive

Thread: Parallel Pliers
27/11/2019 12:54:02

I have a set of Maun Industries ones. They do a whole range of different types at not cheap but affordable if I really need them prices. **LINK**

Mine are Type 4951-160. Well made and very useful. Fine, cross grooved jaws with a slim tee groove running longitudinally down the middle of one jaw face. Strong wire cutters the outside too. **LINK**

These were UK services issue so sometimes turn up at military surplus places.

Clive

Thread: Back saw for cutting steel and brass?
27/11/2019 12:42:02

Probably a real unicorn hunt these days but maybe look out for a set of Starrett 249 Screw Slotting Blades. Like these **LINK**

As I recall it 4 different widths in the set. They are 8" long and fit a standard adjustable hacksaw frame. Fine tooth blades with no set on the teeth.

Basically a really skinny file with deep safe edges.

Discontinued in the 190's I think. Probably a very slow seller as few folk had need of such and even fewer would know about them.

Clive

Thread: Inside chuck jaws
26/11/2019 17:28:39

Interesting job Martin.

Reminds me of the eye-wateringly expensive 8" and 4" scroll type lens mounts originally made for the incredibly expensive Ealing Research Optical benches (**LINK**) which used a similar pin system to move the jaws. Given that the ones I had in the lab had something like 0.1 micron centring repeatability if used with care the price was probably justified. Certainly I never needed to worry about things going back in accurately.

Small picture is the only one I can find on t'net of the Research bench. Cat iron, monster heavy and three sets of slides co-linearly accurate to better than tenth of a thou over the whole 6 ft + length. Only part of the kit shown. I had pretty much everything in the heirloom quality, glass doored, mahogany cabinets with a fair few multiple duplicates. Lord knows what it cost Her Maj back in the day, certainly beyond insanely expensive. In the catalogues but never priced. Probably buy an entire street for a similar amount. Not a short one either.

All skipped by an ass with a PhD after I left.

Clive

Thread: VFD off the bay
26/11/2019 12:29:35

Peter

"Reliable" is a very broad church. Industrial running every day at close to rated capacity is hugely different to occasional home shop use on a lightly loaded machine. Home shop types pretty much never approach the real metal shifting capacity of a machine, especially not industrial capable varieties, simply because dealing with large quantities of chips at high velocity is such a major league pain.

Issue with E-Bay import, whether "no brand" or "who they" brand, is that you don't know the standards of manufacture. Worse the E-Bay supplier generally doesn't either. Technical back up being essentially non-existent too. At best the inexpensive ones are devices from third or fourth tier makers. At worst a bunch of "surplus" standard line parts, which may well work but be below specified performance, assembled by outworkers in their back rooms. Things from the bottom end of the supply line probably haven't been turned on, let alone tested, before boxing up for dispatch. Which is worrying.

These days it can probably be assumed that the semi-conductor side of things is at least adequate, however marginally. So magic smoke release soon after purchase is rare. Although I'd be chary at running "no name" at its full rated capacity. The PCB boards on cheap import won't be up to industrial standards but should be good enough for the job. Probably unwise to let the shop get damp tho'.

For me the big issues would be the quality of the capacitors feeding the DC bus, how effective the safety components are, how good the control software is and whether or not the control software has actually loaded properly. Inverters are notoriously hard on their capacitors which are a consumable item needing periodic replacement after sufficient operating hours. For good quality ones probably more hours than home shop use will rack up. But first quality ones are expensive. Almost certainly the place where a lower end maker will shave quality. In practice probably fine unless they shave too far.

Fundamentally you just don't know for sure what you are getting. Something from a decent third or fourth tier maker ought to be more than good enough for home shop guy but at the back end of an E-Bay supply chain finding out what you actually have is hard. Heck some of the third and fourth tier brands have been knocked off by the build in a back room crowd. Just because the one Jack got at super bargain prices last year is still running fine it doesn't follow that the one you get will still be good. Jack might have been lucky, or hardly uses it, or its only on light duties or ....

Personally I can't be bothered with the risk. For me the objective real £sd difference in price between "has a good chance of being just fine" purchase off E-Bay and the real thing from Inverter Drive Supermarket or a similar supplier isn't worth the potential issues.

Your mileage, and depth of pocket may differ. Mine certainly would have done 40 odd years back when every £ really ought to have done the work of 5, or even 10 if I could manage it. These days I'm a bit more affluent and, at 65, have to seriously factor in how many good years I have left and what I want to spend them doing! Paying a bit more for "just works like it says on the tin" is attractive.

Clive

Thread: Inside chuck jaws
26/11/2019 08:21:17

Jaw tooth to scroll engagement is essentially single point contact in the middle for all sroll chucks so the teeth probably aren't significantly weaker. Especially not in smaller sizes.

In practice the major disadvantage from the user perspective is needing to change the jaw positions when going from inside to outside mode and viky versa. Far too much confusion potential, especially on the shop floor.

Making the things has to be considered too. Obviously harder to do a dual purpose set of jaws and maintain reasonable concentricity both ways. Remember both sides of the steps have to be good both ways round.

Nothing impossible but it all adds up. When two sets of jaws is the standard that everyone is used to and the manufacturing is sorted there is little incentive to change unless the bidirectional jaws have significant cost or performance advantages. Generally seems to have been seen as a cheaper expedient for small chucks so quality suffered a bit making the idea even more niche.

If bidirectional jaws had been the original standard odds are two sets would have been the niche.

Clive

Thread: Colchester Student Mk1 Won't Start
25/11/2019 21:00:42

Just looked up the PC40 manual. Its a static converter so it needs the lathe motor running to produce a reasoanble approximation to three phase.

The control gear coils must be connected across the 220 V mains input lines to work. The third leg is generated by the motor itself so no power there until its running.

Probably not man enough to run the motor properly under load but it ougth to start it off load. In my view frustration in a box. Static converters can be seriously weird devices, especially when you get much over 1 hp rating and often don't behave how the books claim.

Although, as Andrew says, rotary converters can be made as a single phase motor driving a three phase generator the term is generally understood to refer to a basic static converter driving a matched, permanently connected, three phase motor. That motor is frequently termed a pilot motor. It acts as a generator to produce the third (wild) phase leg and somewhat stabilise the voltages, currents and phase shifts of the three legs os that you can simply connect and run a machine without too much fiddling. Most boxes use an ordinary motor but, ideally a specially wound device should be used that isn't quite the same as a motor.

Most static converters can be made into an adequate approximation of a rotary converter by adding a pilot motor. Best to use a big old fashioned one rather than a modern high efficiency one. So called "Energy star" motors can be pants at this. I always used to use a motor somewhat bigger than the converter, eg add 5 Hp motor to a 3.5 static converter to make a 3 hp rated rotary.

Despite what the commercial producers like Transwave may have you believe getting things working really well is more black art than plug'n play. Seem to be lots of pertinent research papers from the wind power community about making Stienmetz (the fancy name for the circuits and wiring involved, connected devices work better. Pity none of it has made it down to affordable workshop level kit.

Clive

25/11/2019 19:43:54

Long time since I had anything to do with rotary converters but I'm not sure that a 3.5 hp (nominal) converter is going to be enough to reliably start a 3HP motor. Especially an economy one like the Clarke.

One common issue with a marginal system is insufficient voltage to operate the control gear. The control gear should always be connected across the mains input leg nor one side from mains and one side to the generated (wild) leg. Theoretically it should matter with a rotary converter, although vital wit a static converter. In practice that and similar issues have caused me serious frustration in the past.

Clive

Edited By Clive Foster on 25/11/2019 19:44:17

Thread: 1P 240V Lafert Motor In Colchester Student Lathe - Wiring Help
25/11/2019 18:33:03

I agree with John that the motor may be a capacitor start & run type and that the blue box is a start capacitor with there is a relay in the box controlling the start capacitor. However there are two types of relays that can be used for this duty.

Current operated relays are generally used for capacitor start motors with the relay coils in series with the run windings. When the motor is up to speed the current drops opening the relay and taking the capacitor out of circuit. They can also be used with capacitor start and run motors connected as described by John but there is an alternative set up using potential relays.

Potential, voltage, operated relays are used with capacitor start & run motors. The relay coil connects across the start winding and disconnects the start capacitor once the voltage is high enough to indicte that the motor is up to speed. The main capacitor remains in circuit connecting the "live" ends of the run and start coils. Start and run windings are joined at the "neutral" connection and "live" power connection is made to the run winding.

I've never encountered such a motor in real life but understand that the start capacitor can be physically surprisingly small due to better control of the voltage across it. General purpose start capacitors need to safely withstand full mains voltage plus a decent safety margin. Capacitors linked via a potential relay only have to be rated up to the relay opening voltage. Current through the coil of a potential relay is less too.

Clive

Thread: Knurling tool operation
23/11/2019 11:06:40

I have ordinary bump knurls, a Brauer hand squeezed 3 wheel "nutcracker", and a Marclo professional clamp type knurling tools. Sometimes tempted to make a DIY cut knurl tool too just to see how well they work.

Rule 1 seems too be use good quality sharp knurls. The knurls do wear, especially if you show them obdurate material. Best to assume the ones on a used "bargain" are shot and that the ones included with an economy device aren't up to scratch. Dunno what were in the Marclo when I got it but a bit of stainless steel put a nice flat on one. Knurling stainless can be iffy due to work hardening but I'm pretty sure the wheels weren't OEM quality. Got replacements from Zoro which seem good, acceptable price and quick delivery.

The Marlco has a hand lever to apply knurling pressure after the basic knurls just kissing the work setting has been made using the screw. Makes the whole process much more controllable as compared to relying on screw feed. Whether via cross slide for bump tool or via the adjuster of the basic clamp type. The nutcracker looks rather lightly built and a bit cheap but works unreasonably well on the more ordinary range of materials. It will do silver steel if you insist but thats being unkind. I'm convinced that the control and feel from hand squeezing or a hand lever makes the difference.

Much internet talk about getting the work size right so the knurls fit round equispaced, gear tooth style. Waste of effort in my view. Unless the job is small and the knurls coarse the difference between dead right diameter and worst possible case is small, a few thou usually. In practice knurling is a combination of cutting and displacement so things soon shave to fit if displacement alone isn't enough. Hence the desirability of coolant to wash away the thin shavings.

If you need the OD dead to size perhaps calculating the start diameter is desirable but I just have at it. Even coarse knurls on a nominal 3/8" diameter shaft went just fine with the nutcracker.

The Marclo is very heftily built. Much stouter than the common DIY clamp designs but can still deflect a little if you get careless. I'm inclined to believe that stoutness is important for easy, reliable results and that the usual DIY proportions are inadequate for anything much over an inch diameter. Being a bit on the light side doesn't stop the DIY breed from working but it just makes it harder as more care its needed.

Clive

Thread: Warco GH1230 and Toolposts
20/11/2019 19:43:35

Phil

Looks to be a stout and reasonably speedy machine.

These days anyone starting out needs to consider whether they are primarily going to use old style HSS or new style inserts before deciding on a toolpost set-up. I'd be unsurprised to discover that, if you have the basic experience needed not to keep breaking inserts whist learning, lifetime costs of HSS in a decent QC toolpost system with a sensible number of holders come out comparable to or even greater than insert carriers in simple block type toolposts. If you have to factor in a good grinder and other kit solely for sharpening HSS, inserts are almost certainly going to be cheaper for hobby / home shop use.

As insert carriers don't need height adjustment simple two slot blocks can easily and cheaply be made from stock metal sections. You just need to devise some way of rapidly and repeatably changing out the blocks without loosing the alignment. If you need to use HSS on odd occasions shimming the tool to height is easy if the block is off the machine.

Good QC toolpost systems tend to get spendy as proper exploitation requires your general purpose tools to be permanently mounted in the carriers with a couple or three spare for special to job tooling. I have 16 or so to share between two lathes with toolpost shimmed so the holder height settings are the same. More normal folk debate between 6 and 10 as being acceptable.

Historically piston type QC systems have been considered less sturdy than wedge or, considering the more professional end, Dickson, Tripan, Multifix et al types. How much is inherent to the geometry and how much due to a combination of relaxed standards allowing a simpler toolpost to sold relatively inexpensively I know not.

The GH1230 looks to be of similar capabiilty and strength to my Smart & Brown 1024 which is quite capable of driving a Dickson hard. If funds permitted I'd be looking at Dickson or a Multifix clone from the like's of Create tooling. If not I'd be making a very close inspection of the particular wedge types on offer. Being limited by QC tooling system stiffness is monumentally frustrating. Especially as even an inexpensive system isn't, objectively, that cheap in real £sd terms.

If I were starting over I'd go inserts with interchangeable, built up from stock sections, two way block posts custom made for the carriers concerned.

Impressed that you get a full DRO set up as standard with the GH1230. But the way its set up would not suit the way I work. Tools from pram to orbit in under 10 minutes I reckon!

Over 40 years at this metal mangling game has convinced me that you can't afford everything so you need to carefully consider where best to direct your money and where corners can safely be cut. I've more money than I care to admit tied up in "seemed a good idea at the time" white elephants.

Clive

Thread: Using the Maplin (Dremel clone) for cutting tool steel
20/11/2019 10:08:13

+1 on the angle grinder with 1 mm disks rather than a Dremel or clone.

I find the extra weight of the angle grinder makes it far easier to do a smooth straight cut. Goes through quicker too which helps. Dremel style machines put the cutting disk rather far out front and its a one handed hold with the wrist in a rather weak plane. Dremel is great when holding an abrasive drum, disk or whatever against the job for fine shaping where you want light touch and sensitive control. Not so good at cutting straight.

As ever horses for courses.

Not greatly enamoured of cutting disks indie grinders either for much the same reason.

Clive

Thread: Quick Machinists Jacks
17/11/2019 21:33:58

By the very nature of things machinists jacks made from joining nuts have a rather small footprint. Makes them less stable than the conventional kind but also means you can squeeze them in where a bigger one won't go.

Several years ago I ended up with a handful of joining nuts left over from a job and considered making some jacks like that. I planned to make larger feet to screw in the bottom if needed to make them more stable and / or bridge the mill table slots. Was going to make my feet round but, on reflection, suspect rectangular ones might be more successful. In reality I'd probably have made feet on demand by poking a countersunk head screw through lump of "whatever" roughly shaped to fit the space and eventually ended up with a collection of shapes and thicknesses that worked for me.

In the event I lucked into several properly made jacks and spacers for "£ very little" before I got round to making mine.

You will almost certainly need some "pointy cap" ended screws to help support less than flat or less than smooth items. Best to make some whilst you are at it. Odds are when you need some you won't have any suitable studding or set-screws to hand. I often cheat when that sort of "Will need it. But when?" thing arises and sequester some material stock. Been 20 years before it got used on occasion!

If using them on a lathe faceplate obviously bolt them through from the back so they stay put. I'm not brave enough to use a conventional machinists jack on a faceplate!

If you have 1-2-3 blocks consider making adapter studs so the jacks screw into the blocks. Sometimes you need a tall support.

Clive

Edited By Clive Foster on 17/11/2019 21:34:24

Edited By Clive Foster on 17/11/2019 21:35:45

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