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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: Cutting 4mm thick MS plate
16/10/2013 23:48:01

The modern ultra thin cutting disk is much easier to control and produces far less sparks than the older thick cutting disks used to. Set the guard right and you will have very little trouble. Unless I'm in a confined space where sparks bounce I find cotton overalls and glasses are sufficient PPE.

Was reminded of the difference between old an new style disks yesterday when my usual 4 1/2" angle grinder wasn't avaliable (the builder doing my extension had it up on the roof with a diamond blade cutting tiles) so I had to revert back to my old 4" Wolf Grindette to chop up some 7.5 m long steel box section into handleble size. Old style 1/8" (ish) thick cutting disk. Talk about pyrotechnics. Until the thin disks came along I'd always considered the angle grinder very much a last resort for stock cutting.

Clive

Thread: Warco VMC electrics
16/10/2013 23:31:51

Copy the circuit used on UK market Bridgeports. Not the simplest way but its professional, effective and just plain right. Bit of googling should find you a manual or PM me and I'll send a PDF version.

Basically the contactor controlling the motor is the master and feeds the contactors for the power feed, coolant pump et al. On the Bridgeport there are mechanically operated microswitches to select feed direction. Also a separate forward / off / reverse switch for the motor so the other drives can be run with motor stopped for test purposes or whatever.

Simplified control systems are a false economy. Takes nearly as long to install as teh full fat version and, in my experience, the simplified bit always ends up biting me on the tail. So I have to do it over, properly.

Clive

Thread: power threading
28/09/2013 14:04:22

With 'undreds of threads to do it probably makes sense to invest in the proper kit :- a coventry die head and an auto reverse tapping head. Far, far faster than the hand way and better results too unless you take great care which, for hundreds, is unlikely simply due to the yawn factor.

They come up on E-Bay fairly regular at acceptable, especially considering the time and labour saved, prices. My Coventry head cost around £35 delivered with several chaser sets which I'm slowly adding to. Order of £5 a set being acceptable to me although a couple of paid for jobs got new ones folded into the price. Pollard tapping heads numbers 1, 2 , 4 & 5 came along at £25 to £30 dleiverd so, like any self respecting toolaholic, I had to have them. By no meanseveryday tools but each time I use them I'm reminded why they are high on the list of things that will need prising out of my cold, dead, hands!

Clive

Thread: Warco GH1322 start up
04/08/2013 14:45:02

I'd guess I'm not the only person on here who would have trouble finding the start lever on that machine. Normally you'd interpret the one arrowed as being a conventional three rod control set-up where the lever on the side of the carriage controls the power feed stop / start & forward / reverse. Like my P&W Model B and countless other machines. Linking it to the spindle power is just plain perverse. Especially if it can also double as a normal third rod system although there doesn't look to be room for the mechanical interlings on that one.

There are darn good reasons why normal practice is to have motor power control (and spindle clutch if fitted) at the headstock end. Extra buttons for direct from saddle control are of course a decent idea on larger machines where the headstock can be a walk away, say 3 ft between centres up, but not for use as the normal thing. Also not totally convinced by clutchless direct drive to spindle arrangments even though my beloved Smart & Brown 1024 VSL has that form of drive. At least the Smart & Brown has things sensibly arranged so that all is obvious with the forward, reverse and (monster) stop buttons falling easily to hand on a big sloping panel at chip tray height. The buttons in a box at the back of the headstock a fair stretch of the way over arrangment on the Warco machine is indefensibly bad in concept. The really idiot thing is that a sensible arrangment as per the S&B, Harrison M250 et al is simpler, cheaper and lots less parts.

Given the price / specifications / dimensions equation such machines look to be attractive for a training environment. I shudder to think of the cock-up potential when someone trained on one of these has an emergency with a big machine having headstock controls and conventional third rod set-up. Yes I kinow you should stamp the tromp bar but when the brown and sticky hits the rotating blades big time its awfully hard to go against what you have always done. Certainly I've stretched for the usuall stop button instead of stamping the emergency in the past (big Pollard pillar drill).

Clive

Thread: Turning tool ?
14/07/2013 15:52:21

Maybe cut the back end off a suitable size holesaw to leave the correct diameter spigot, fix it into a guide sleeve able to run on the outside of the bar and mount sleeve'n saw assembly in the chuck. Peck your way through about 3 mm at a time with plenty of lubrication. I'd weld the saw back together afterwards!

Similar guided holesaw worked for me but my job was short enough that I didn't have to cut the back off. Finish was surpringly good too. Especially as I used an electric pistol drill to drive it.

Clive

Thread: Bridgport Wiring Diagram
03/07/2013 21:56:52

Nick

I have a PDF copy which I could E-Mail or print A3 size.

KWIL

Yes Its the 1979 vintage version of the UK Bridgeport Textron set-up.

Previous version is WD 145. Next version is WD 153 dated 1981.

No significant differences in any of the Textron 1970's to early 80's era drawings. Mostly component layout changes. The few wiring variations are functional equivalents so its not too hard to puzzle out but it does make life harder when sorting the efforts of an ace sparky from Bodgitt & Bend Ltd.

Clive

Thread: BA and MOD D.P. change wheels for modern boxford lathe
18/06/2013 21:22:54

Steve

Mystery solved. These are "Straight sided splines, bottom fitting. Shallow." to BS 2905:1953.

I have an electronic copy of that standard if you need it complete with all the fit data but for the dimensions you have measured the lower and upper limits in proper imperial units for a 7/8 inch (nominal) shaft are :-

D = 0.905 / 0.915, d = 0.7880 / 0.7890, W = 0.2180 / 0.2195,

Note that this is a hole refrenced system so the fit is defined by shaft clearance relative to a tightly specified minor diameter d.

The actual major and minor diameters are derived from an acane concept called effective diameter so its not possible to get the nominal size from shaft measurements. Fortunately this standard is said to be simplified compared to earlier versions as "due to the considerable developments in involute splines in recent years it is considered that 6 splines are sufficient for all classes of work requiring straight sided splines". The original standard covered 4, 6, 10 and 16 splines whilst its replacement provided tables covering from 8 to 80 splines on shafts from 1 to 10 inches diameter. Yikes!!

Side comment.

Your metric measurements are what is known as a "soft" conversion so great care is needed to accurately sort the clearances and fits. Funny numbers are likely. Hard conversions adjust the sizes slightly to get sensible numbers for nominal dimensions comprehensible variations for limits and fits. Hard conversions are great in the drawing office and factory but can be a right pain in the field where replacement parts made to hard conversion standards are just different enough to the original not to fit as intended. Something to be wary of where replica parts for old stuff is concerned.

Clive

Edited By Clive Foster on 18/06/2013 21:24:11

Thread: centering the chuck
08/06/2013 14:09:15

Hi Becky

Lots of decent advice above but, in my view, its "get you out of jail" stuff. Handy when you have no other options but far too much faff for general use.

Best, and correct, solution is to get a four jaw chuck and use the indicator to set things up as accurate as you need. Once in practice you get decently quick at the mount up and indicate business. The old boy who claims he can set stuff in a four jaw as fast as you can use a three is exaggerating but not vastly so.

Various tricks to speed things up. For example if doing several parts the same size only release two jaws at 90° to make the change. Once you have the knack in intial setting and changing things will go back to rather better than a thou (0.02 mm). Another time save is to have a quick mount set-up for the indicator. My old Heavy 10 had a flip down chuck guard pivoting off a rod above and behind the chuck running parallel to the bed. I made up some simple bracketry to mount a Verdict indicator and fine adjuster rod from a magnetic base kit on the spare part of the chuck guard rod. Four four jaw work I'd leave it all mounted and just pivot it out of the way when turning.

Realistically its unreasonable to re-chuck work in a 3 jaw and get it to run true whatever you do. My best 3 jaw is a Pratt Bernard precision one bought new (ahem) "several" years ago when I picked up a very nice Heavy 10 lathe. £ 500 for the lathe £ 550 for the chuck as I recall matters and significantly less than 0.5 thou error last time I measured. Even that isn't good enough to reliably re-chuck work without faffing.

For small jobs consider a master-slave system where you make a suitable carrier to go in the chuck and put the job in that. Theoretically you get perfect results if you make the carrier and do the job with it still in the chuck. In practice its pretty acceptable to mark the carrier so it can be aligned with the correct jaw to go back in the right place when re-mounting. Maybe a little twist ajustment using the indicator for reference if you want things to be just so.

Clive

Thread: BA and MOD D.P. change wheels for modern boxford lathe
08/06/2013 13:29:16

The easiest way is to get a change wheel listing from another lathe and convert as required to suit your leadscrew pitch and gearbox settings. For example my metric Smart & Brown 1024 lathe has a 4 mm pitch scew and the book gives details of the additional gears needed for BA, Mod and DP. If it will help PM me and I'll do you a copy of the relevant table, heck I may even ahve it in Excel format set up for a similar calculation.

Splines are pretty standard. can be done with a single tooth keyway shaping cutter if you are patient. I'd shift the bulk of the metal using suitable size small drills before boring out the centre. Given that use is likely to be very low a bit of low cunning should come up with a way to share one splined hub between all the extra gears. Being a crude sort I'd probably take a hole saw to one of the gears you have!

As JS says the splines are overkill for the power to be transmitted, the 1024 has only a single key smaller than one of your splines.

Clive

Thread: Cutting the centre out of a solid workpiece
22/05/2013 17:08:23

Check how well the material machines first. If its a decently behaved alloy then trepanning or hole saw will work fine. If its pure aluminium or one of the ill mannered alloys that share the sticky, gummy, "build up on the tip as soon as look at you" characteristics of the pure stuff accepting the waste and mess of turning to swarf may be the sensible option. Even if you have a suitable rotary table and set-up stuff drilling a ring of holes is hardly worth the effort.

First steps in trepanning go a lot easier with something well behaved, OK true of everything but more so in this case. I frequently use the hole saw method but last week lost a tooth from a brand new Starrett holesaw, which promply wrecked the rest, due to assuming the scrapped component source meant well behaved material.

Whether hole saw or trepan Jasons advice to go from both sides is good. If hole sawing remember you can only go about half a tooth deep before having to withdraw and scrub out the chips. Need a top brand holesaw. El cheapos will melt thier teeth on this sort of deep job and, probably, be so far out of round that they jam.

I'd probably just drill 6 or 8 half inch holes in a suitable circle and whack a chisel through the left behind webs. Sometimes crude really is all you need.

Clive

Thread: power hacksaw
21/05/2013 23:21:49

For what its worth my Vee belt drive Manchester Rapidor has a two stage reduction coming out around 13 or 14 to 1 reduction. Approximate pulley diameters are 80 mm on motor and intermediate shaft, driving 260 on the intermediate and 300 on the saw crank. Wave a tape at it guesstimate as the saw sits at the end of my big lathe and I'd need to pull it out and unhitch a cover to measure properly.

When you get it going do remeber to bolt it down as they tend to wander around a bit if unrestained. The Rapidor moved a couple of inches per hour of operation on a smooth "underfloor boarding" floor before being restrained.

Clive

Thread: Moore and Wright 2000 micrometer?
18/05/2013 23:13:04

If its in good order there is absolutely no doubt the M&W is a far better device. Designed from first principles as a digital micrometer using a linear glass scale with moire fringe sensing its basically a hand held version of the high quality Hiedenhain probes used for precision scientific work, CMM and similar accurate measurment devices. Non rotating, spring driven, measuring rod with speed damping for constant contact pressure it really does tick all the boxes.

Specification is ± 0.002 mm, better ± 0.1 thou, accuracy and they mean it. It really does deliver that accuracy on the bench given the basic care in handling essential when working to such fine limits. Generally instruments with such capabilities are either lab only or have a heavily hedged specification applying in certain circumstances if you do it right and probably mutter the corect incatation. Demoable in the lab but a different matter out in the real world where parts made in my shop need to match parts made in yours. For example the common mechanical micrometer with tenths reading vernier makes a pretty fair fist of indicating a few tenths variation as the acceptable error over any given thou is sufficiently small that the vernier is adequately accurate. But which tenths you are talking about is acompletely different matter because you have no idea where in the overall permitted error band the particular thou you are trying to split into tenths lies so any idea of true measurement is a fantasy. Unless you calibrate the specific thou(s) of interest with gauge blocks first.

All completely academic to the average model engineer but it would still be alovely thing to own. This thread on another forum may be of interest:-

http://www.vintage-radio.net/forum/showthread.php?t=91570

Clive

Edited By Clive Foster on 18/05/2013 23:15:59

Thread: Motors to drive tools
12/05/2013 21:35:37

The Kennedy we had in the departmental workshop also had, like the one bricky refers to, a flat belt drive. From memory the pulley on its 1/4 HP "square" Hoover motor was around 1" diameter and crowned but the saw pulley was a simple flat section approaching 8" diameter.

Given the faff factor in making a countershaft and the effectiveness of multi Vee belts on large diameter flat pulleys it may well be easier / cheaper to find a small multi groove pulley for the motor and cut a suitable size flat disk to go on the saw. Older washing machines, spin driers and small electric mowers are potential donors of useable size motor pulleys. If you have a micrometer setting bed-stop its very easy to make a multi-groove pulley. A simple Google search will soon turn up a site or catalogue listing with the groove size details. Small pulleys aren't exactly expensive if you insist on cheating!

Clive

Thread: DSG Motor, again.
11/05/2013 18:19:59

Don't underestimate the frustration factor involved when setting up a "distressed" pulley to run true for re-machining. If you haven't got a good bore to pick-up on a good deal of creativity may be needed.

What size belts? I have a couple or three 8 inch pulleys about the place which I shall never use, including a nice double B sheaves taper lock fitting one, which could be re-homed for a modest number of drinking vouchers.

Clive

11/05/2013 13:09:51

 

Taper lock bush system is the quick "professional" answer to this sort of problem. The system uses a split bush with parallel bore and taper outside. The pulley has a matching taper bore into which the bush is driven by cunningly arranged screws thereby causing it to contract and grab the motor shaft. Hard! There is an equally cunning extractor arrangement.

The system is, apparently, by no means as spendy as it used to be. For example the Bearing Company offer bushes and pulleys at relatively reasonable prices. See http://www.thebearingcompany.co.uk/product.php?id_product=5293and http://www.thebearingcompany.co.uk/category.php?id_category=29. There are plenty of other suppliers, not to mention a certain auction site. (Heck I may have one on the white elephant shelf as I bought wrong size in error some time back and had to get a different size but whether 28 mm was the right or wrong one I dunno!)

Obviously a suitable pulley needs to be available. The range is wide, but not exhaustive, so some compromise on speed may be needed.

Clive

PS sorry can't get the link to truncate.

Edited By Clive Foster on 11/05/2013 13:15:08

Edited By John Stevenson on 11/05/2013 13:54:00

Thread: Snap.
05/05/2013 18:54:39

Just because something is patented doesn't mean it will work as promised. And that won't. The screw arrangement is fundamentally pro tilt and the thin sheet guides under the square guide ways are grossly inadequate to hold the jaw down.

I have a pair of Vertex 4" jaw width vices with similar, albeit much more robust, guide arrangements with the moving jaw something over 6" long. Mine have a pin and through hole arrangement to locate the feed nut enabling 3 opening ranges to be selected with a maximum of 8". The wide range is handy but its essential to keep an eye on the relative positions of moving jaw and base being prepared to deal with lift and/or tilt issues in the out third or so of the opening range as the moving jaw extends beyond the base by some 3" at maximum opening. Its never been a big problem for me and certainly up to around 6 inches or so of opening jaw lift / tilt is no more an issue than with any well made vice. On the rare occasions when I need the maximum opening I'm prepared to work a bit harder simply for the convenience of a wide opening vice that I can actually lift!

If there is sufficient metal in the body to put a second set of grooves inside it could be made to work reliably by adopting a system similar to that used by Orange Vice Company. They arrange the feed screw to operate in tension and drive the moving jaw from a sliding block running in a slot beneath the top surface of the vice. The drive block and jaw connect via a pair of interlocking wedged teeth acting to pull them together as the vice is tightened up thus actively preventing jaw lift and tilt. When tight the top jaw and block sandwich part of the vice body between them so things shouldn't move. The Orange Vice website is here, look at the specification section and parts diagram A will show you how they do it. Some pretty subtle engineering involved.

Clive

05/05/2013 13:56:41

Very unsound looking geometry there. Can't see it ever working reliably with a conventional screw as the short moving jaw has very poor anti tip geometry. There are good reasons why the standard vice configuration has a long moving jaw despite the inherent space inefficiency. Best option if you don't scrap it would be a rebuild to incorporate pull down / anti tip geometry into the nut. Kurt are the well known exponents but most of the quality CNC vices have their own versions.

Somewhere on the net there is a good description of how the Kurt style system works with how to do a DIY equivalent details. Pretty sure I down loaded it but darned if I can recall where, or even if, I filed it. I rather fancy a smaller version of the Orange vice which uses a very similar base section and has an on-line parts list that appears to be well enough illustrated to permit successful "inspired-by" re-engineering and replication into a variant more suited to that size.

Clive

Thread: Broken Spoke Removal
27/04/2013 23:12:53

If you can get it up onto a vertical mill a centre cutting carbide end mill should do the deed by cleanly removing the core leaving the thread behind as a sort of spring shape for you to pick out. 3 or 5 flute ones can be found. I used a 5 flute one to shift 4 (I think) broken 2.5 mm taps. Lost a flute on the last one but still finished the job. £5 or so to save many hours of work seemed a bargain. Stainless should be easy in comparison.

Down at those small sizes HSS needs a bit too much babying to keep the cutter in one piece especially with dissimilar materials getting in on the act should a bit of run out occur.

Clive

Thread: Engler Viscosity.
27/04/2013 15:28:30

Best to check with Castrol Technical, I've always found them very helpful. Should be OK from the lubrication angle but if there is a pump fed distribution system with orifices to control how much oil goes where the thinner oil will upset the mutual calibrations and may also lead to too much oil being distributed. Can't see the difference being so great as to starve anything but orifice or other restriction controlled oil feeds are something of a black art.

Clive

Thread: Top slide problem
27/04/2013 13:48:57

Hi Graham

Interesting to know that a ball bearing will do instead of a proper pressure pad for a lock screw. As the contact between ball and gib is essentially point I'd have expected the action to be more bending the gib rather than pushing it so the effective "brake" area would be very small. I guess that it works because the actual gib movement involved is, probably, around a tenth of a thou or less so there is pretty much no room for the gib to bend or distort. Not sure if I've got the bottle to try it tho'!

Clive

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