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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: Bandsaw Blade Flash welder help needed please...
24/04/2017 10:33:16

The welder fitted to my Startrite bandsaw is made by Ideal. A simpler unit than yours but pretty sure it works in the same manner.

When welding bandsaw blades on this sort of machine the blade has to be fitted into the jaws with the ends butted together and a suitable space between the jaws. During welding the jaws are pushed together by spring force ensuring that a solid weld is made. The jaws move closer together during this process. Both the projection of the blade during initial set-up and the spring force applied during welding vary depending on the size of the blade.

On mine the left side lever is labeled Upset Way and the right hand one Upset Pressure. Like yours the right side jaw is fixed and the left side one moving.

My Upset Way lever has detents defining the clockwise and anti clockwise movement end stops. The anti-clockwise detent is un-labeled, the clockwise one operates the weld power switch and is so labeled. The lever swings freely between the detents, shifting the left side jaw back and forth as it moves, with calibration markings for different blade sizes. This lever enables the correct initial projection of the blade to be set ready for welding.

My Upset Pressure lever has several blade sizes marked with detents for each size. It pushes the jaws together with increasing force as the blade size increases. I would expect yours to have detents for each size of blade too unless the faceplate is common to several machines and some variants are unable to do some sizes. Might be easier to omit detents than do a whole new faceplate.

Basic operation is simple enough. Cut the blade square. Mount in the jaws with appropriate projection as set by the Upset Way lever. Set Upset Pressure for the appropriate blade size. Set Weld Current switch, top left on mine, to the blade size. Turn Upset Way lever to the weld position for the specified time to make the weld. When the blade has cooled release the jaws and take the Upset Way lever back to the un-labeled anti-clockwise end detent. Adjust the balde position in teh jaws so the weld is central then do an anneal cycle with several short heats to cherry red followed by a short cool down. Anneal switch is top right on mine.

Finish by grinding off the weld flash so the blade is a constant thickness.

Clive.

Thread: Couple of things at Lidl
23/04/2017 11:46:19

Work and gardening gloves are always worth looking out for at Lidl as they are usually sold in proper number sizes so you can get a nice fit. The rough neoprene (?) palm ones are the bees thingies for liftin'n shifting as the palm is strong enough to give protection, thin enough that you can feel whats going on before the priceless (imitation) Ming vase or unobtainum cast iron part escapes and rough enough to give a better hold than bare hands even on oily or slippy stuff. Not exceptionally sturdy but at under £3.00 thats no great issue.

A real boon for folks like me with small hands, either size 6 or 7 being a good fit, where the normal Small, Medium, Large selection are actually one size. Too big and too floppy!

Clive.

.

Thread: Making a radius/blallturning tool using a boring head
22/04/2017 19:23:41

This link **LINK** shows an interesting variant with the ball turner integrated into a QC system toolholder. The boring head is also pulled back into the carrier rather as I suggested in my earlier post.

Were I to make another that is probably the design I'd use as a basis with appropriate modifications to fit my Dickson QC system. More work but having an integrated unit makes it easy to fix the tool height dead on centre. If you merely put it in a carrier when required it has to be adjusted dead on centre before you can use it. Not as easy as it seems due to the inherent flop around tendency.

Clive.

22/04/2017 19:06:13

I based mine on the design by Reed M Streifthau given in the second part of this link **LINK** .

I made the spindle with a female R8 taper so I could share the boring head with my Bridgeport. Didn't bother to invert the adjustment system so as to put it on top. Don't find it any great disadvantage with the adjuster on the bind side. No separate bearings. Just took care to get an accurate fit with really good finish on both bore and spindle.

A basic boring head is probably around 2" longer than the compact slide assembly used in most purpose built designs. So you need to pull the head as far back to the mount as possible. If the tool projects too far there won't be enough slide travel to bring the tip back onto centre line. Something to watch closely with smaller machines. I didn't pay special attention to this figuring there would be plenty of room a as my lathe is a 10" swing Smart & Brown 1024. although it fits fine there isn't a lot of excess slide travel, maybe 1/2". I figure a bit more attention to detail would have won another 1/4" to 3/8" and might well have been needful on a smaller machine. The pain shank carrier shown in the drawing on the first post can certainly be pulled back a bit further than my R8 spindle version. For smaller machines it may well be worth enlarging the body slightly so the flange on the shank assembly can be pulled back into a counterbore winning even more space.

Well worth the effort as it works just fine.

Clive.

Edited By Clive Foster on 22/04/2017 19:06:57

Thread: Couple of things at Lidl
21/04/2017 22:50:47
Posted by Bandersnatch on 21/04/2017 22:39:38:

Flash forward to Summer 2017 - what's that fuzz-ball of swarf on the front of your lathe, Gary? You been turning cast-iron again?

Wrap it in cling film before installing, one layer across the front won't be noticed by the magnetism. Remove and carefully unwrap when the fuzz ball, ferrous bits or whatever get too objectionable. They come off with the cling film and can be shaken into the bin.

Cling film or a thin plastic bag also works well when you need to use a mag base in swarf ally. Plastic bag usually easier with a mag base.

Clive.

Thread: Can you identify this engine?
18/04/2017 10:49:43

If it is completely home built and home designed you can't be sure that no showstopper errors have crept in somewhere in the process. Doesn't take much to stop a basically sound design from running. Hardest part is to make a well behaved carburettor. After you have done all the basic timing, cam lift and duration checks to ensure the basic design and assembly is reasonably sound easy start spray would be best way to confirm that its capable of running.

Looks to me as if the carburettor is Amal style. Probably along the lines of the old "standard" type. If so the float chamber and main jet both look to be too low relative to the venturi so the mixture will be all over the place and almost certainly too lean for it to start. if you can beg or borrow a modern appropriately sized carburettor that might give you abetter chance of getting it going.

Carburettors are hard.

Crude option would be to find a Wal Phillips fuel injector, basically a drip feed jet on a venturi with a throttle plate. Just adjust the gravity feed head until it runs! Brutally crude but they do work quite well and, so long as the jet size is within reason, pretty much anything that can run will run. Look fairly easy to make if you had basic dimensions.

Fair bit of work involved but rewarding once its going.

Clive.

Edited By Clive Foster on 18/04/2017 10:50:17

Thread: Tuscan motor .55kw induction motor
17/04/2017 22:32:28

Swarf, Mostly

Ooops. Should have checked a bit rather than relying on memory. T'net is interesting but not totally helpful. Looks like modern "dispensers", apparently thats the right name for what we see on forecourts, use most varieties of pump. Petrol has a low viscosity and lubricity so producing a long lasting positive displacement pump sounds fairly challenging. Surprised to see that gear pumps can be made to work well as sliding surface areas are, inevitably, large and can't be sealed off from the liquid being pumped. So relatively low lubricity probably doesn't help.

Interesting to be reminded of how difficult it is to accurately measure volume delivery. Especially with a liquid like petrol which has a relatively large coefficient of thermal expansion.

Clive

17/04/2017 15:45:55
Posted by Neil Wyatt on 17/04/2017 11:28:37:

Just a thought, repeated stop starts can heat a motor more than continuous running.

Neil

Probably not an issue with that motor as its intended for fuel pump use where it will have to cope with many starts per hour with only short run and cool down periods. As ever its down to design optimisation for particular duties.

Design load is a centrifugal pump which has a light load at starting load and low to mid rpm so you don't need so much ooph on start-up. Hence start winding can be smaller and currents lower. So heavier wire can be used than with a conventional motor which needs to be able to start under load. Lower current plus heavier wire means much less heat generated per start so can manage more per hour without problems.

As always its a case of selecting the most appropriate design compromises for the job. With a standard motor limiting to a few starts per hour is worth the gain from lighter wire in the start winding which saves space and leads to a more efficient motor.

That one hour run time specification is more a reminder that the heating and cooling thermal time constants of the motor have been considered when selecting it for the job rather than a hard limit. If you don't run at full power for long periods its quite likely you will never get it warm enough to need a cool down rest. But if you do overheat it remember that it will take along time to cool right down again. It takes a fair while for all the heat to wander out from deep inside the windings.

Check that it doesn't run hot on low or zero load. Its not uncommon to find that motors optimised for a very well defined type of load will run very hot off load drawing disproportionately large currents.

Clive.

Thread: 'Zero carbon steel'
15/04/2017 22:39:51

Just a "dodge the Enviro-Nazis" label.

Refers to how the steel is produced. For example an electric arc furnace fed with scrap steel is, according to industry definitions, zero carbon because no carbon dioxide is directly produced and released during the steel making process. Carbon dioxide released by the generating plant supplying the electric arc furnace doesn't count.

Clive.

Thread: Tuscan motor .55kw induction motor
15/04/2017 13:56:40

Wonder what the effective duty cycle is for motors on Home Shop machines? I imagine long runs would be at least partially offset by tea / coffee / buttie breaks. Plus high load use will most likely be limited so normally running at reduced power ought to help keep temperatures down. Inclined to think that 1 hour maximum at full load and nominal 50 % duty cycle overall would be enough.

Clive.

15/04/2017 10:44:51

Unfortunately that motor is probably run time limited. Its pretty well sealed as its designed to live outside in a fairly leaky box and has no fan or external fins so it will tend to warm up as it runs. For filling station petrol / diesel pumps design maximum duty cycle would probably be in the 50% range on a run for a few minutes filling the vehicle, wait a bit until next customer pulls up sequence. Typically the wait would be rather longer than the work unless things are really busy. Motor probably has an over temperature protection device inside it. Either it triggers after an hour or it takes an hour to cool down and re-set.

I'd be unsurprised if it were the latter. Way, way back in teenage days I had a Saturday job on the pumps and recall one pump being unable to cope with the Saturday morning shopping time rush. After about two or three really busy hours it would go on strike for an hour or so then work as normal. Which sounds like motor temperature overload device. Normally 5 of us on duty for 8 pumps and we'd be on the run from 10 am to 1 pm so it had to work for its living. Don't recall it ever being fixed as the whole pace was refitted a couple or three months after it started messing about.

Clive

Thread: Wich way up and were to fit dehurst referse switch
13/04/2017 17:19:37

Best practice is to set it vertical with the operating lever at the top with screws or bolts though the holes in the back onto a suitable bracket or machine surface. The alternative is to lay it on its back with the lever at the front. Wiring should run through proper armoured protection sleeves anchored in the large holes in the base.

Should be connected after the contactor / DOL "switch" / NVR switch. A Dewhurst is by design very slow actuating and will suffer contact erosion if used as a power switch. Used as direction selector before turning the power on it will last pretty much forever.

Clive.

Thread: Yaskawa VFD
13/04/2017 13:58:00

With a VFD the worst case demand is the switch on surge to charge the capacitor bank providing the DC supply that the VFD chops up to generate 3 phase AC. If you happen to switch on at just the right point in the incoming AC cycle you get a very large inrush current for, relatively speaking, quite a long time. Enough to take out a quick blow fuse unless its very overrated relative to the nominal steady state draw.

Ages since I had owt to do with this sort of thing but I think worst case switch on point is around 150 volts.

Ideally the switch on should be remote via a relay and zero crossing detector so the actual switch is at zero volts letting the capacitor voltage rise alongside the AC input rather than trying to jump from 0 to a high voltage. Fuse suggestions imply that your inverter is direct switch on not zero voltage controlled.

Clive.

Thread: Alternative to PC based Cnc controllers
12/04/2017 11:28:41

Bambi, Jun-Air and the other lab / dental compressors are excellent and very long lived if you don't exceed the duty cycle (40%?). Bambi is quietest. Tanks are a more useful size too. But even on the little doughnut tank its a bigger lump than it looks in the picture. Market seems to have decided that £100 - £150 is the used price range so you'd be doing well to get one significantly cheaper than that Makita. Similar units to the Makita with other badges but Lawsons price seems to be biggest bang for buck at the moment. Obviously a "made for our badge" device but I'd trust Makita more than some of the other folk offering what is almost certainly essentially same design unit under the skin. Lawsons are decent to deal with too. My first stop for mail order power tools and similar.

Autojack are about the only breed that commonly comes up at a significantly lower price for similar oil-less low output compressors. But their idea of quiet is fantasy land "at only 96 dB this is easily one of the quietest compressors on the market". Ahem. You really need under 60 dB to be unobtrusive, mine claims 57 dB and is.

Clive

Thread: Dore Westbury 5" machine vice?
12/04/2017 11:05:59

If castings can't be found a version glued'n screwed together from stock sections looks pretty easy to sort out if chomping the base from solid is a bit too much for your mill. Obviously you still need to machine all mating surfaces for accuracy and good fit but it doesn't seem a major chore.

Do it the neat freak way with countersunk socket heads from underneath into blind holes doing the screw bit and who is gonna know without a close look. I'd not be doing with short blind holes. Just run right through and knock the protruding threaded ends off during clean up machining. Probably need to be a bit thicker than the original, maybe 1/4" to 3/8" to get decent thread lengths and screw seats. Which hardly seems a major issue.

Screw in tension of course, pulling from the back, with decent cleanly surfaced and well lubricated thrust washers. Not jut run on the body. Needle roller thrust washers without the needles work well being noticeably smoother than a simple machined step running on the body.

If you do make one from scratch seriously consider making it replaceable jaw style with a stash of soft ones and a couple with Vees in horizontal or vertical planes. But do them when you make it! Soft jaws for my machine vices would be easy to do but I never get round to making a stash and no time mid job so always work-around and second best solution time.

The major issue with the Dore Westbury design compared to many conventional vice designs is that there is no central aperture so drilling through holes is pretty much out. But it's lower profile, very resistant to jaw lift and much wider opening. Yer pays yer money and makes yer choice.

Clive.

Thread: Alternative to PC based Cnc controllers
11/04/2017 22:26:52

That Makita compressor looks good value. About half the output volume of the Compact 106 suitcase compressor I have with similar pressure capability and reservoir size for something around 1/4 the price. Checking the manual its another intermittent use DIY device. Maximum of 20 minutes use per hour advised. However, according to the wiring diagram, at least its got a proper motor start - stop regulator so it should be possible to keep within the 33% duty cycle.

I'd set it up with a bigger external tank so it has a decent run. 5 minutes or so sounds good. Then a decently long wait before it comes on again. You will need to be anal about leaks tho'. Takes very little to stop these low output compressors from getting up to their rated pressure.

Clive

Thread: DIY Powder Coating
08/04/2017 13:02:27

Seen plenty of rubbish powder coat jobs pushing, peeling and cracking away to hold water and promote rust just as vintage engineer says. Not anything like as much of a problem as it used to be tho'. Back in the 1970s and 1980s it wasn't uncommon to see jobs with adhesion between coat and substrate being little better than heat shrink tubing. Properly done modern efforts are getting up to the standards of old style formaldehyde based stove enamelling which I've known sandblasters to just give up on as it proved virtually un-shiftable in reasonable time.

Spraying powder onto a cold substrate always seemed wrong to me. Would have thought a warm to hot substrate would promote better adhesion. Not hot enough to cure but hot enough to ensure that it rapidly comes up to melting / curing temperature at the interface during the process. Seems to me that if the substrate is cold the coating is likely to cure round it rather than sticking to it as, with external heat, the curing process surely proceeds from outside to inside.

Clive.

Thread: Rivet and Bolt cropping
06/04/2017 21:59:26

Search for "rivet cutters UK" on google turns up a few likely candidates working on similar principles to the multi-function crimp-shear-stripper pliers in your picture. Expensive to very expensive tho'. Intended for aluminium rivets but some offerings look very hefty for that job.

Flat face wire cutters, as used by piano tuners, work pretty well on small ones. Best to get the double lever semi-parallel action type as these leave a near flat end. Less of a squeeze too. Sorry I'm not sure what the real name is, they look very similar to common nail extraction pinchers.

Be careful not to overload yours. I've had to weld 3 sets back together so far! Also the coloured sleeve bullet et al connection crimper doesn't make a "to specification" crimp and won't cover the full range of wire sizes each sleeve is supposed to take. I'm glad I splashed out on the proper thing. Paid for itself in about 6 months on do-overs for folk who used the basic one and were getting too many failures. Probably around 10 to 20 % were turning up bad so for much of the time the simple tool was doing a decent enough job.

Clive.

Thread: Martin Cleeve's Dog Clutch
06/04/2017 21:41:46

I think Hendey originated and patented the single tooth dog clutch concept around 1900 -1910 era. Surprised how few machines used it even after the patent expired. My Pratt & Whitney has one, as do most of the big Holbrooks. Its a really nice system on a three shaft control machine.

Only unique thing about the Hardinge implementation is its ability to run at high speed. My P&W says de-clutch before engaging above 250 rpm or thereabouts. Holbrooks have similar speed limitations. Headstock off job on both if you shear the clutch dog. Fortunately usually fixable but a lot of heavy work to get in. Hafta do mine someday as its cleary suffered although still working fine in sensitive hands.

Clive.

Thread: A Tirril Regulator question?
05/04/2017 19:06:45

Technically no.

The Lucas and similar dynamo controllers control the field current directly so they are simple vibrating contact regulators.

In contrast the Tirril regulator controls the field current in the exciter which in turn drives the alternator field coil(s) so it manipulates the relatively small current in the exciter field coils to control the much larger current in the alternator field coils rather than attempting to control the alternator field directly.

Clive.

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