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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: Machinist level
17/03/2022 09:02:19

Don't be tempted to get a really sensitive vial for "extra precision".

The thing will drive you nuts as it will seem that the bubble moves every time you breathe. A level built like that can't sensibly work as a master precision level for detail structural reasons.

Typically sensitivity will originally have been be around 1 or 2 minute of arc per division. Say 5 or 10 thou per foot, 0.3 to 0.6 mm / metre. Which can be quite frustrating enough on a bad day thank you.

Handy calculator here **LINK**

https://www.calculand.com/unit-converter/?gruppe=Angle&einheit=Millimetre+per+metre+%5Bmm%2Fm%5D

so you can see what the numbers mean in terms of real distance errors.

I still say my old fashioned 6 base, WW2 vintage, screw adjuster gunners clinometer is the least frustrating way of getting an accurate level.

Clive

Thread: Inverter or converter
14/03/2022 17:52:37

The plug and play digital phase converters sold by Drives Direct are an effective substitute for proper three phase mains supply. Mine is well over a decade old and doing just fine.

In principle nothing particularly clever about them. Just a normal style of single phase inverter with voltage doubling rectifier on the input. In practical the clever bit is making it work properly and seamlessly. Back in the day lots of folk offered voltage doubled inverters that sort of worked up to a point on E-Bay et al.

Not cheap. Price is similar to with Transwave converters of similar rating.

You can also get rather less costly Chinese made 380 volt nominal output inverters which should be able to run the lathe and mill motors without major wiring changes. Basically just bypass the existing controls and use the inverter buttons instead. They are said to work OK but I'm a little unconvinced as the suppliers seem to be E-Bay type "list and send" folks without proper technical back up.

Clive

Thread: Welding on an old Startrite Motor
14/03/2022 17:36:28

Jon

Far safer to weld onto the bracket rather than motor case. If you must.

I'm no fan of welding in that sort of situation as it makes life harder if you have to change things. My late mate Andy the Randy reached for the welding gear first on pretty much any job 'cos it was quicker than making bolt on brackets like wot I did. I still say he spent more time cutting off, griding and re-welding than I did drilling and bending.

I'd just make a bracket to share the motor mounting holes.

However if you plan to use the VFD controls on the box rather than make up a remote button pendant putting it on the motor will be way too far back for easy driving.

Given the low motor power the VFD box will be compact so it could easily be mounted on the left side of the machine in front of the rotary switch so the speed display and buttons face you.

I was impressed by a picture of one mounted that way with a lever to operate the rotary switch alongside. Presumably the maker had arranged bearings behind the VFD to capy the lever witha fork, slot or similar to operate the switch. Red ball on the end of the lever so as to be obvious whethre switch was on or off. Presumably ball forward was on, ball up or down off.

Never really cared for the standard switch on the side location as it's slow tor each in an emergency if you don't fit an additional stop button.

Clive

Thread: Inverter or converter
14/03/2022 16:19:25

Robert

Given the current prices of name brand VFD boxes from the likes of Inverter Drive Supermarket (my go to) and other reputable suppliers the Transwave converter system is not really cost effective for your proposed use. In your situation as a non-electrical person the big win of a converter is that it is simply plug and play with no need for modifications to the machine electrics.

I'd set up permanent lines to the machines with an isolator in the way rather than swopping at the converter. Lets you put the converter out of earshot. The buzz of the internal motor and transformer can be obtrusive.

I suspect that if you have the set-up professionally installed and signed off you will need separate plugs and isolators anyway to meet current regulations. I like the yellow bodied with red lever control ISO isolators made by Lewden for this sort of thing. Not silly expensive and its obvious whether things are on or off, even from right across the workshop. Can be hard to find tho'

20 amp version here **LINK**

https://www.powerdiscount.co.uk/lewden-iso-20-isolator-20a-4-pole-ip56-59886-p.asp

Same thing under ERL brand **LINK**

https://www.electroreplacement.com/erl-4-pole-isolator-switch-20a-35a-45a-63a-max-415v-ip66

I absolutely don't approve of the round knob isolators because its hard to see if they are on or off from any distance.

If your motors are dual voltage and you can find affordable help with the wiring changes you will only need two inverters. The extra load of the suds pump and mill feed motor swill not worry a decent brand inverter. Especially if you don't exploit the speed changing capability of the VFD and simply use it as a 50 hz source.

That said most dual voltage suds pump motors work fine using the "capacitor trick" to run off single phase supply and its arguable that having a three phase feed motor tracking spindle speed makes life a little easier when milling. Most relatively modern feed motor systems use DC motors run off a transformer connected to one phase of the 3 phase supply which can easily be transferred to the normal single phase mains supply so no need to connect to the VFD anyway.

But you will need to find help if you are not confident with electrics.

Clive

Thread: Cross-slide fixture plate considerations
06/03/2022 15:36:49

Harrison offered a vertical slide as an official accessory for the L5 machines which are of similar size to Calums Cub.

The was one with the L5 we had in the section workshop at RARDE but it was never, to my knowledge at least, used. Pretty hefty piece of kit. Bolted on in place of the topslide.

Calum

I've only used the Thor Labs breadboards as fixture plates. Certainly fine for anything I wanted to do but all small stuff where standard vices and Bridgeport slot fitting clamp sets were too cumbersome. 6 mm in alloy is pretty darn strong if you get a solid face to face joint and reasonably filled hole or slot.

Clive

Edited By Clive Foster on 06/03/2022 15:43:37

06/03/2022 14:21:19

Calum

Maybe consider one of the solid aluminium breadboards from Thor labs as an alternative to making your own.

**LINK**

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=159

Only 1/2" thick and holes are M6 on 25 mm centres rather than your preferred 10 mm but its a lot easier to buy pre-holed rather than DIY and the extra cost / less work ratio doesn't seen stupidly unfavourable. Thor were quite happy to take my crdit card for a one off some time back.

Newport supply similar things at similar prices but I've not bouhgt from them direct via credit card.

**LINK**

https://www.newport.com/f/sa2-solid-aluminum-optical-breadboard-plates

Regards

Clive

Thread: Chipbreaker lathe Parting Blade
04/03/2022 09:31:22

Malcom

Assuming I haven't got the numbers uddled up this is the J&S42-S tool holder you are talking about :-

**LINK**

https://picclick.co.uk/Jones-Shipman-JS-No42-S-Parting-Off-Tool-114744285597.html!

It is made to hold bevel edged Eclipse (or eclipse pattern) blades. They need to have the correct angles on top and bottom to sit securely in the tool and be held properly by the eccentric gripper. Very little tolerance on depth as the eccentric gripper doesn't have much eccentricity. The factory blade is a slide fit in the slot.

Not my favourite parting tool because that bulge on the bottom enforces a fairly large minimum stick out when used with a block, four way or QC holder. Probably designed to be used with a US style lantern post.

Over the years I've hoovered up a couple or four with box of tooling purchases. At one time I considered grinding the bottoms off flat. Either enough to sit the base of the tool on the topslide so its securely braced or flat right along so I can be pulled back into a four way or QC holder.

If used as standard with a QC the stick out can help with clearance problems between the toolpost block and tailstock if you have a crazy cramped set-up. Similarly the bent variety could be useful in cramped situations. Not that I've ever seen such needs in 45 or so years of mucking around with lathes but .....

Clive

Thread: Threads that are steel and epoxy
01/03/2022 09:36:23

Don't know about JB Weld but I have done similar mixed material threads with Devcon metal loaded filler whch worked out OK. But this was basically filling in a Dutch keyway so the original thread was mostly complete and could be used as a guide. Devcon is significantly harder than JB weld and takes threads pretty well itself. My impression is that a thread in the steel filled version is about as strong as one in aluminium.

Keeping the tap straight will not be easy. If there is any significant offset the tap will want to run into the softer JB weld. Serial taps driven under power in the mill is probably the best that can be done i a home workshop. But care an patience with hand taps should get the job done. Preferably with a guide.

As Hopper says the amount of JB weld left should be pretty minimal. Most likely just short bits of male thread and similar part filled female bits. Its likely that these will come unstuck and be dragged out with regular use of the drawbar leaving a very ratty all metal thread behind. Unless you are very lucky your re-tapped thread will not align with the original so the actual tread will be somewhat reminiscent of the spiky efforts on the metal inserts used on cheap furniture where a thread needs to be put into wood to hold a bolt.

Albeit female and rather little more complete. How complete being in the lap of the gods. Could be nearly complete and just a bit slack, could be horrible. Basically are you feeling lucky.

A little inadequate for drawbar threads on an arbor methinks. If the opening threads are poor the drawbar will not insert cleanly and its threads are likely to be damaged.

Sensible thing is to cut your losses, bore it out and loctite a decent threaded bush in.

Clive

Edited By Clive Foster on 01/03/2022 09:40:36

Thread: Sieg / Syil spindle on y axis
27/02/2022 14:46:50

Jason

Apologies for not keeping up with things. Hadn't realised that the SX2.7 had enough travel to reach the edge of the table. The little Taig CNC on my other bench that I've never got round to using pretty much can too.

I appreciate that the castings and other details are modified to be more CNC orientated rather than simply doing a factory version of a DIY bolt on bits conversion to a manual machine but the overall concept is still very similar. Presumably for manufacturing cost / performance / capability ratio reasons. Generally when you look into the "Why did they do it That way when This way is (theoretically at least) so much better?" the answer tends to be "Wanna pay two (or three or X ) times as much!".

Industrial, enclosed, CNC VMC machines are generally inverted compared to manual machines with smaller tables running on longer ways so you don't have the limited dovetail engagement at extreme travels issue. Expensive to make but great for rigidity. In exchange you have work-holding issues, if you want to exploit the full machining area there is nowhere for hold-downs to go.

Its arguable that a table narrow enough for the spindle to cover the whole Y axis travel is too narrow. A bit of extra width on the outside for hold-downs, clamps, positioning fence for repeat jobs et al is very useful at times. I drive a Bridgeport these days and clamping, work holding et al can be a right pain when the area to be machined approaches the table width.

After a bench top mill I thought a 9" x 42" table would be more than enough! Third job said "Nope!". But I'm home shop guy working in 12" to the ft scale, not model maker. My biggest job, so far, was 14 ft long.

Clive

27/02/2022 12:15:33

Fundamentally these are manual machines with CNC bolted on afterwards.

With the exception of Deckel and Bridgeport style mills it seems to have "always" been normal practice for manual mills to have restricted Y axis travel towards the column so the outer side of the table cannot be covered by the spindle centre line. I've no idea whether there are fundamental engineering reasons. Its just the way things have "always" been done.

Similar to the unreachable ends of the table at the left and right ends.

I guess it provides safe space for work-holding devices like the common step bolt and strap sets.

Whether this was intentional right from the start of vertical mill evolution or whether some mills happened to be made that way and the spare space was found useful so it became the norm I know not.

It seems clear that vertical mill design evolved from the simple drill press, which inherently has unreachable table space, rather than the planer which is able to machine over its whole table. Presumably a matter of price / performance ratio back in the early days as a simple "drill press with x-y table" layout would have been less costly to make.

Modern full on industrial Vertical Machining Centres are made so the spindle can cover pretty much the whole table. To eyes used to manual vertical mills the tables look very small. Especially in relation to the big box enclosure.

Although possibly more objectively accurate, specifying machines by the actual area covered by the spindle rather than by table size would not be a successful sales tactic!

Clive

Thread: Hand Hacksaw
27/02/2022 09:39:50

I bought three cheap Hilka branded high tension style hacksaw fames maybe 45 years ago when such frames first became common outside of the specialist market. Having three frames means I always have 18, 24 and 32 tpi blades ready to go so not tempted to use the wrong tpi to save changing hassle. Not perfect but quite satisfactory in use although the adjuster threads on two stripped out of the alloy nuts fairly recently. Easy fix.

Wing nut adjuster below the frame isn't terribly obtrusive in use. The projecting stud and nut on the front of a conventional folded steel Eclipse et al frame gets in the way much more. My old Eclipse has an abrafile in it. Down to my last 6 abra baldes!

Being three piece construction, square steel tube to bar with two die-cast ends, it was easy to modify them to take 10" blades as well ast the design 12".

I'm unconvinced by the line-up issues. Straight cutting is more technique than observation. Need to look from the side anyway to start but once cutting the blade is always hidden by the frame if you stand straight. Sideways observation needed to actually see the blade seems to me a good way to promote off axis cuts.

Clive

Thread: Sieg / Syil spindle on y axis
25/02/2022 18:18:33

Matt

Fundamentally the issue is the weight of the head and cantilever stiiffness of the spindle assembly relative to the column dovetails.

Putting the spindle further away from the column to increase coverage of the table needs a deeper and, obviously heavier, head. The heavier the head is the harder it is to lift it by manual means.

Being further away from the column the spindle has more leverage relative to the dovetails which reduces stiffness unless the column is correspondingly beefed up.

The standard sizes and travels seem to provide acceptable price / performance / weight / cost ratios for the person who buys one new. To get more table coverage from that design appears to need a bigger, heftier, more expensive machine. Given the relatively shallow pockets (by machine tool buyer standards) of the target market more sophisticated design and components that could allow greater table coverage are simply unaffordable.

That said I'd like to try turning the column sideways and mounting the head on a short stiff tube. There are certain strength and stiffness advantages to that layout. Whether such an asymmetric machine would sell is another matter.

Clive

Thread: I want chips
25/02/2022 08:53:16

As Hopper says chip breakers are primarily for breaking up thicker swarf. On industrial size lathes taking industrial size cuts the thick birds-nest effect can be very dangerous. Thick, stiff razor sharp random coils take a deal of unwinding.

If you do put a simple chip breaker on a tangential tool it just goes straight down as you re-grind so its not wateful. Needs a steady hand to keep it in the same place tho'. I imagine one of the thin angle grinder cut off wheels would do the deed nicely but I'd want a jig.

Adding a step needs a proper jig to put the narrow faces in front of it on.

I suspect that you still won't get nice chips. Snail shell roll seems more likely. Something I often get with a parting tool. Such rolls periodically break off when they become too large. I suspect that on most of our size jobs the roll will break at the end of the chip rather than becoming large enough to break mid cut.

Clive

24/02/2022 21:40:40

Tangential tools are inherently prone to continuous ribbon swarf because the cut material flows away relatively freely. The flip side of lower turning forces and good finish from the clean cut.

Chip breakers work by imposing a sharp bend on the ribbon swarf as it flows across the tool causing it to fracture. Cooling of the hot chip adds to the stress making fracture more likely.

The geometry of a tangentila tool makes it harder to generate a really sharp bend to promote fracture. On conventional flat tools a semi-circular (ish) groove immediately behind the cutting edge is a common way to a mke a chip breaker. Wasteful of tool steel as the whole groove has to be periodically ground away after a few sharpenings otherwise the tool has to be thinned down to the base of the groove.

An alternative, but not quite as effective is to put a sharp step close behind the cutting edge. Less wasteful of tool steel as the top remains at the full tool steel depth and the step can simply be moved back on resharpening. Especially if you don't use back rake along the length of the tool. For the depths of cut normal with smaller hobby lathes I'm skeptical of the value of such rake anyway.

A step is pretty easy to add to a tangential tool and is not wasteful of material.

Clamping an extra piece of thinnish steel above a conventional flat tool gives much the same chip breaker effect as a ground in step. Most economical on tool steel but you cannot use back rake and there is a risk the the chips could get under the separate piece, particularly so if the tool projection is significant. Although simple and pretty effective it's not a very common method, mostly due to the perceived risk of things going awry. Generally not suitable for common tangential type holders. Often old style top clamp carbide holders were arranged so the clamp acted like a chip breaker of this form. Easily done with the simple flat, usually triangular inserts that were common many years ago.

Clive

Thread: Parting tools and inserts
24/02/2022 13:33:44

When it comes to parting off inserts and holders its best to use the same make of inserts and blade. Tolerances and shape of the gripping region are very tight so generic inserts may not fit quite well enough for long life or reliable holding.

Insert should be stronger than the blade. I've snapped the hold down tongue off a Kennametal blade. Insert was still serviceable. 15 years and counting has gotten halfway through my first 10 pack of inserts and onto my second blade,

As ever with parting off its rigidity, rigidity, rigidity that matters along with feeding dead square. My Dickson QC toolposts live dead square to the lathe centre line so no set-up issues. I have a cunning plan for rapidly resetting square should I ever move the toolpost or adjust topslide angle. Would be unsurprised to discover that a major reason for folk getting better results with a rear toolpost is simply that its worth spending the time to get it dead right and, once its right it stays right. Swopping tools around its tempting to accept close, very close which may not be close enough this time rather than take the extra time to get it just so. Getting just so really needs test cuts too. Impractical mid job. QC toolposts should make swopping relaible but they have been known to move a touch during a job.

I tend to run insert tooling at normal HSS turning tooling speeds and HSS blades at half to 2/3 rds HSS turning speeds. Almost invariably with spray lube to help the chips get out. Even the folded chips from an insert, which are narrower than the slot can get stuck up. Running at higher speeds makes it easier to keep the chips thin and flexible for easy escape. Hand feeding whilst grinding along in back gear is a serious exercise in patience and thick, inflexible chips are almost certain. Not good.

If you have a Dickson style holder, like DMB, make sure your blades have the correct bevels to match the holder on them. Allegedly some of the inexpensive sources of both blade and holder are bit sloppy in both the angle of the bottom lip and that of the body the tool sits against. Tolerances are deceptively strict to ensure that the blade doesn't pop out and sits with clearance both sides. Thats why they are expensive and rarer than the other styles.

Relatively easy to make a new top (gripping) wedge for Dickson holders to take blades of next size down if you luck into a wrong size stash. I have T2 size holders and did so after a 5 blades for £5 bargain turned out not to be deep enough! 15 years and counting on the first blade.

Clive

Thread: Early Deckel horizontal mill FP0
23/02/2022 18:22:38

Assuming you mean the mandrel that carries horizontal milling cutters normal practice is to have a taper on the end matching that in the spindle with a threaded drawbar running through a hollow spindle to hold it tightly in place. Its quite likely that the drawbar would have also been used to close the collets that were used to hold cutters directly in the spindle nose.

The outside end of the mandrel is usually arranged as a simple plain bearing to support the mandrel with sufficient endwise clearance for all end thrusts to be dealt with by the spindle.

Hopefully you have at least one collet so the type can be identified and the spindle taper derived from it.

However looking at the early brochure pictures on the lathes.www.co site its not clear whether on not the spindle is actually bored through. Some picture might have a drawbar sticking out of the end but its a matter of interpretation. iIf the spindle is solid the collets would have been closed by a nut running down on the external thread on the end of the spindle. Rather after the manner of a modern ER collet. Som eo the lathes.www.co pictures appear to show such a closer nut. If the spindle is solid the mandrel will still have a taper matching the spindle nose but a captive nut fitting the exteranl thread will be required to to hold it in place.

Clive

Thread: I need help to identify shaper
22/02/2022 09:19:47

The screw adjuster at the back of the ram to help accurately set the stroke endpoint is unusual and may well be a unique refinement on such a small shaper.

Klopp and Heinmann had similar adjusters on some of their large machines but they always cast the name onto the machine. As far as i'm aware they didn't make shapers that small either.

Clive

Thread: Always confused over threads and tapping
20/02/2022 09:16:47

1/4" x 20 is UNC or maybe ANC, its American ancestor.

Although 1/4" Whitworth is also 20 tpi the designation is 1/4" BSW.

British practice has always been to name the common range of standard "tap'n die for fixing things together" threads so you get a diameter and a letter code that is a contraction of the name. In the UK if it a UK native specification thread has a x TPI suffix applied it is in greater or lesser degree specialist. Cycle is probably the only one that has an x TPI and can legitimately be considered common enough to be non-specialist.

Correct common UK practice would be 1/4" UNC for 1/4" x 20. This should also apply to the smaller number series, preferably with a No prefix. No 6 UNC for example. The potential for confusion with BA is obvious. American # prefix is probably clearer.

However most references tend to follow the Zeus book practice by tabulating the numbers as either ANC for coarse and ANF for fine. Which is what they are. The UN series imported the American specifications, as tided up for wartime use, wholesale for the smaller sizes.

American style number - TPI designation is common in the UK too and probably as correct as anything. As far as I know BSI is silent on this but there is probably a military standard that ought to be definitive.

American practice tends towards diameter x TPI or number - TPI, often with # in front, although applying ANC, UNC or one of the other less common specification identifiers isn't uncommon. Usually only done when it matters as the differences are of littile import for standard fastenings. Tables of sizes are generally headed NC, NF, ANC, ANF, etc as appropriate.

Tolerance classes are rare in normal bolt things together work whatever the thread. In practice equivalent to modern h6 / H6 class is assumed. Probably class 2 as Michael says.

Particularly when it comes to wartime production some of the tap and die designations can be - ahem - odd. If I've not broken it I have a BA tap lurking somewhere with the diameter in decimal inches and a pitch in mm! Also had / have some Whitworth and BSF sizes with the exact diameter in decimal inches. A few thou off nominal size. All American made from quality firms. I suspect that in the days before tolerance classes exact size designations were the American way to get tight or loose fits as needed. presumably for plated items.

Clive

Edited By Clive Foster on 20/02/2022 09:22:35

Thread: Milling machine ems-i dro pickup damage
19/02/2022 20:52:19

The EMS-i manual for your console should have the pin out / socket in connection details for the scale.

Looking briefly at one of the manuals I hoovered up when considering buying an EMS-i system the scales appear to be standard TTL level quadrature output types. Unfortunately the D type connector pin assignments aren't completely standard between makes so you will need to verify that any scale of a different make has either the same pin-outs as the original or, if its different, that you can get an adapter cable.

M-DRO list the connector pin assignments for the scales they sell and have a range of adapter cables so it should be possible to sort out a suitable replacement. As far as I'm aware the scales M-DRO supply have the most common connector pin layout.

Clive

Thread: Crank handle method and sequence
18/02/2022 21:54:55

Last time I looked you could find acceptably close copies of the genuine fixed handle for around £10 to £15 out of China from the usual suspects. Might well have to modify the bore and keyway but that's far easier than making a copy from scratch.

Even with Andrews hydraulic copier to help.

I'd probably just go Beaver style. Chomp a bit of plate down and affix a shoulder bolt with a bit of tube running on it for a handle. Very much a place where pug ugly but "Well it works." is plenty good enuf. But if you haven't suitable stuff to hand that won't be much cheaper than a copy.

Power feed Bridgeports should have freewheeling handles so getting clonked isn't really an issue. But best to make sure they really are free running as there are places where the impact from a stiff one will still make your eyes water. If you don't know the tricks unsticking a stuck up freewheeler can be frustratingly hard. Once you have got it free there is a fairly tricky knack to twisting the grip so the drive pin remains engaged when turning. Even after 15 or so years I still sometimes drop the drive mid adjustment.

Clive

Edited By Clive Foster on 18/02/2022 21:55:40

Edited By Clive Foster on 18/02/2022 22:11:38

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