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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: Back plunger indicators - does anyone use them?
20/01/2020 21:55:30

As Howard says the angle of view can be better than a conventional plunger type in many machine set up applications. Especially if you have the full set of Starrett (or other make) accessories. Ultimately the standard plunger style indicator is intended for quality control purposes when mounted in a stand rather than machine set up. Which doesn't stop it doing a perfectly good job when needed but I suspect folk who have properly learned to exploit the back plunger type may get along a little better.

Hafta say I grabbed my Starrett Last Word set with all the bits very cheaply (probably due to it being stuffd into a three layer pencil case rather than a proper box) maybe 30 years ago thinking "This will be very useful.". Yup so useful that I've literally never used it! That said my 5 standard stye ones average around 2 or 3 outings a year at most. The lever types and Blake Co-Ax knock off do all the heavy lifting.

One thing in the set that really out to be useful is the "extender seesaw" thingy which can be poked something approaching 2 1/2 inches down a bore.

Clive

Edited By Clive Foster on 20/01/2020 21:56:05

Edited By Clive Foster on 20/01/2020 21:56:22

Thread: Dunlop Taper Bushes
20/01/2020 18:07:12

Agree with Tim about going to "bearing suppliers". I got some bolt on ones from Engineers Mate some years ago which were fine. They still list such things, not cheap tho'. **LINK**

Clive

Thread: Buying metal - caveat emptor.
20/01/2020 09:46:03

Even buying whole lengths is no protection. I bought several full lengths of allegedly bright EN1A from a small local supplier approaching a decade ago and reckon there were at least three different types of steel in the bunch. Different heat treatments and conditions too. Judging by how they behaved when turning and cutting probably only 3 of 8 could be rightfully treated as close enough to EN1. First part I tried to thread was rather worse than Robins first example. Starting some way back down the bar too. The good bits threaded beautifully.

Fortunately most of that particular job was rough work. Bit about that long with a hole about that size sort of thing. But a couple of lengths were going into stock. Sorted good ones for that. Still not exactly the same tho'.

Dropping into stuck record mode we really need to stop buying steel by EN numbers and use more modern designations. 230M07 rather than EN1A for example. The EN specifications are just too sloppy to work with these days, especially as there is little control of material condition. EN3B is a good example. Nearest is probably 070M20 but if you get bright bar it could well be 080A15, which should be supplied with a test certificate to show the properties match adequately. That one doesn't matter much as folk like us will be hard pushed to notice any difference between 070M20 and 080A15 when machining.

There is a lot of overlap between steel grades. We are more concerned with condition, which generally defines how it works, than exact composition. If it waddles like a duck, quacks like a duck then it is a duck. But if, metaphorically speaking, you order duck and get bombay duck on the plate you are, I think, entitled to be a bit miffed. Which is about what happened to Robin.

It would be nice if we could find someone with plenty of experience in the modern supply chain able to give appropriate modern designations for materials that will work well for us and have consistent properties regardless of supplier.

Clive

Edited By Clive Foster on 20/01/2020 09:47:02

Edited By Clive Foster on 20/01/2020 09:47:35

Edited By Clive Foster on 20/01/2020 09:48:00

Thread: Drilling holes using pillar drill - work wobbling
17/01/2020 11:32:26
Posted by Hopper on 17/01/2020 00:05:53:

Even when drilling holes where you want to "float" the vice around so it can find the right position as you poke the drill tip into the centre punch mark etc, it's safest to have the vice bolted down but with the bolts/nuts left loose enough to allow some movement of the bolts in the slots etc.

Perhaps a point in favour of the notoriously sloppy, affordable, import cross vices! As I've said before mine is good enough to quickly bring the work under the drill in, hopefully, dead nuts alignment. However if it is a touch out there is sufficient slop for the drill to bring the workpiece exactly where it wants it with no risk of the whole kit and caboodle being slung across the workshop.

A very large drill running slowly can also wobble the table on my big Pollard 15AY floor standing drill. That machine has proper square section vertical ways for the table to run on and a double screw jack to lift it. My gibs are set so it lifts and falls without undue effort so clearances are very small. But a big drill on bottom speed can still wobble it. There is provision to use one adjuster as a table lock screw but I've never bothered to actually use it. Given that it appears to have been painted over in the factory around 1950 something when, I think, the drill was made Mr Pollard clearly didn't consider it very essential for normal folk either. But there for the just in case jobs.

I get the impression that most folk are far too tentative with drill feeds and speeds. OK the book values probably assume good lubrication but push it in firmly at something approaching the correct speed and it will settle in cleanly without wobble. If you pull back before the drill has reached full diameter and the cut surface has visible radial ridges running across it you are probably not feeding hard enough and quite likely running too slow. If the grind is a bit off centre or one cutting lip doing all the work this sort of thing is much more likely. Despite what the experts say hand sharpening drills properly is a considerable skill needing regular practice. A good jig system is far better for normal folk. Unfortunately all the affordable ones are, objectively, imperfect in greater or lesser degree. Often "crap". Some tools should just work. Properly. Its wrong that it takes Graham Meek or someone of equivalent skills to figure out how to rework a commercial product so it does what it said on the tin.

As Mike said a pilot hole the size of the chisel point is plenty. The more of the cutting edge actually engaged in the workpiece the more stable it will be. Nibbling a mm or a few tens of thou off the edge is a recipe for disaster, probably wrecking the drill in the process. I have a, fortunately, elderly and duplicated drill with approaching half an inch from the end down undersized by 80 thou due to being forced into a pretty hard workpiece to enlarge the hole. Needs must and sacrificed for the job but the final kick to getting my Clarkson drill grinder attachment sorted and fitted as being the only think I have capable of bringing it back to size with a truly central point.

Clive

Thread: magic 127 TOOTH ?
15/01/2020 12:08:21

Out in the real world where folk simply need to cut a metric pitch on an imperial lathe the great advantage of the 127 gear is that it allows things to be done in an orderly fashion that can be simply tabulated. Mostly requiring only one gear to be changed for a useful range of threads.

The other effective tabulations using standard gears tend to hop around with the changes needed. Generally something of a pain. Rodericks table is about the neatest I've seen in that respect. Some versions are horrible.

Its all pretty moot if you have a screw-cutting gearbox. 127 is usually the only practical way of going about things. Especially as the folk who made the lathe usually provide you with a spiffy table of what to use when.

Generally the conversion set-up is the only compound gear train needed for the normal range of threads with most screwcutting gearboxes so its frequently practical to leave the 127 gear permanently mounted. My metric Smart & Brown 1024 has a nice roller bearing stud for the intermediate, 120 tooth, gear in the gearbox driving gear train. The metric to imperial conversion uses the 120 driven - 127 driver pair so it was asimple matter to bore out the 127 gear and bolt it on the outside of the 120 gear to align with the gearbox input gear in its conversion position. Changing from metric to imperial threading is now a simple matter of pulling off the spacer and standard 120 tooth gearbox input gear behind it then refitting the spacer followed by the appropriate gearbox input gear. A considerable improvement on the standard process which requires the banjo to be removed and the roller bearing stud replaced with a plain one before fitting the standard conversion gears.

imperial conversion r.jpg

This set-up has cost me 4 module pitches and, I think, 3 small BA pitches which worries me not at all.

I imagine something similar could usefull be devised for other machines.

Clive

Thread: Hobbymat MD65 - help figuring out accessories (photos)
15/01/2020 10:51:57

Swarf ingress is a common problem with locking plungers on QD type toolposts. Given the generally close fit of the moving parts its amazing how much gets in over the years and, eventually, seriously interferes with the operation. Dismantling is usually simple once you have a clear mental picture of how things work.

The operating cam is made by cutting away part of a round spindle so the cut out allows the plunger to move under the influence of an internal spring unlocking the toolholder. In the locked position the plunger is forced against the toolholder by the part of the operating spindle opposite the cut away portion.

Theoretically you just move the plunger back against the spring and wiggle the operating stud around until you find the magic combination of positions that aligns the bores in the toolpost and plunger with the full spindle diameter. Then it simply pulls out. Unsurprisingly swarf or other gunge inside renders things somewhat unco-operative so it can be difficult to feel exactly when proper alignment is achieved. Yours, I think, pushes the plunger forwards to lock the toolholder making them intrinsically more tricky to dismantle than the type that pull the locking device back eg Dickson. Much cheaper to make though. The eternal conundrum is a not so good design you cna actually afford preferable to a better one that needs serious saving up for.

As ever once you have the knack its usually pretty easy. I advocate stripping, cleaning and lubrication on a yearly basis. Mostly to ensure that the thing will come apart to service when needed without undue verbal encouragement.

Before applying too much force its worth verifying that there are no pins, setscrews or similar helping locate the cam spindle. I've never seen such but thats no proof that it isn't sometimes done.

Clive

Thread: Bridgeport & Transwave - Help Please
14/01/2020 21:06:01

Vince

Yes the transformer that runs the control gear is normally connected to L1 but on an older machine its best to check by tracing the wires through. Same with the Transwave converter. Just because there is no reason for someone to mess with things doesn't mean they haven't been played with.

These days I always check that sort of thing first. On balance it probably saves time as maybe 30 to 50 % of the well used equipment I get to see after the "Help" call has simply been messed around with. Simply putting things back to book works often enough to impress folk and, if it doesn't, at least you know where you are starting from.

Chris

As the Bridgeport pancake motors are shorter and larger diameter than the usual run of motors I imagine the design parameters are a bit different. There are a lot of different ways of making motors with similar nominal power but different operation characteristics, let alone any price / performance ratio considerations. Back in the days when VFD boxes were expensive "professionals only" devices with a 9 ft long list of parameters to set I imagine it was possible to set them up to get the best out of pretty much any type of motor with no risk of seriously reducing the lifetime. These days inexpensive inverters will be basically set up for the common varieties of motor which may mean they are hard on other types. Its a pity there is no easy way for the non expert to know if a particular inverter type or combination of set-up parameters is unduly stressful for any particular motor. Although Bridgeport pancake motors are known to sometimes react badly to inverters leading to shorter life the very non specific nature of when problems occur suggests that its basically something in the combination going out of the safe area.

I imagine a modern, decent brand name, self tuning vector drive VFD can set itself up to be much kinder to a motor than an ordinary lower end, non vector device.

Clive

14/01/2020 10:09:01

As Chris says there is some evidence that Bridgeport motors and Transwave converters don't play well together unless everything is just so. Presumably some interaction between the motor design parameters and Transwave design parameters pushes everything to the edge.

Basic rule is make sure that all the control gear runs off the incoming mains driven phase. Both the others are generated and will have no power from a static converter until the motor is running. Transwave a s breed are sensitive to cable losses. You need a good incomer supply from the utility to the house and a hefty cable to the workshop. At least double book size is desirable in my experience.

If you have the switched auto-manual reset overload devices on those old contactors its worth checking for proper operation and giving a good dose of switch cleaner. They are known to get a bit iffy after many years. Probably 'cos they pretty much never operate and get bored after sitting in one place fot 50 or more years.

Old Bridgeport motors have a certain reputation for not lasting well when hooked up to a VFD. Hard to be sure how much is inherent and how much is just plain age. I know of Bridgeport motors that have failed after some time on a VFD (5 to 10 years). I'd prefer to use a decent branded VFD and, probably, fit inline filters to reduce switching stress. Bridgeport motors being seriously non standard its worth spending a bit more to be safe.

Despite what you may read on the Internet from "Build your own converter" mavens converters are not inherently simple "follow the diagrams and plug the Lego together" devices. Over the past decade and more the renewable energy folk have put considerable effort into engineerign analysis of the Steinmetz motor connection set-up on which all converters are based. All the papers I've seen involve very serious maths. None claim to be comprehensive or even the last word in however a limited fashion.

I've long put converters in the "If it works it works. If it doesn't it doesn't." category. Well D'oh! By that I mean something that, if you don't make a silly mistake, will work after a fashion and can usually be refined into going better but if it refuses to co-operate after the initial basic checks prove out its not worth expending great effort trying to make it go. Even if you do get it going after a fashion its never going to be properly satisfactory.

How do I know! After the fourth game you begin to get the idea.

My Varispeed Bridgeport ran adequately off very old MotoRun 4 hp (?) static converter, albeit with the switches set differently to what the book called for on a motor of that power. Worked a lot better when I added a 5 Hp pilot motor to make it a pseudo rotary converter.

My pal Mikes Bridgeport was very hard work to get running reliably on a Transwave 5 hp rotary converter. Like Chris we had major issues with it not running reliably for long periods and occasional refusal to start. Eventually after much swapping of phases and re-arrangement of wiring we found a set-up it was happy with. I had meters, experience and a comprehensive vocabulary of swear words to help. These days it would get an hour of playtime then a VFD but that was not a financially viable option back then. Subsequently we had similar issues with a Hydrovane compressor, which did get a VFD after an hours worth of playing! Mike subsequently spoke to Transwave and they advised seriously uprating the cable between his workshop and the mains incomer. Poking around afterwards showed everything else in the workshop to be working much better on the big cable.

Clive

Edited By Clive Foster on 14/01/2020 10:10:11

Thread: What Vice should I buy (2019)
12/01/2020 10:37:07

As you already have vices take Johns advice and use them for a while keeping notes of the sort of jobs where they prove inadequate. Then go out and buy what you need either as a replacement or supplement.

Do remember that your machining and set-up style evolves in conjunction with your equipment and the jobs that you do. I didn't have a properly useable machine vice when I bought my Vertexes. Just the rather sad Abwood and a Nippy drilling vice. Over the years I've learned to make best use of the Vertex pair. If I had different equipment I'd probably do things differently. I suspect that if I'd had a smaller vice or two, like yours, a two piece style, like the castings in MichaelGs' picture would have been next on the shopping list. Would have been doing rather more work clamped to the table too so appropriate tooling for that would have been needed. A time expired 4 jaw chuck arranged to lay flat on the table might well have been on the list too.

Do consider the weight issue. Big vices are heavy and correspondingly hard to handle. (My back muscles have spasmed and locked up tight for the past couple of days. More than a little uncomfortable so I'm really not going to forget about that.) One reason for getting my pair was that I was having serious doubts over manhandling the 6" Abwood after I'd finished re-furbishing it. Couple that with a show offer and the rest is history.

In my experience, for folk like us, the extra jaw width of a 6" / 150 mm vice when compared to a 4" / 110 mm is of little benefit. Its the wider opening where the bigger vice scores as most vice capacity is "square" where opening equals jaw width. A 4" can be really limiting if you need a support or holder in the vice jaw as well as the work, eg a Vee block to hold a round part vertical.

Clive

Edited By Clive Foster on 12/01/2020 10:39:00

Edited By Clive Foster on 12/01/2020 10:39:47

11/01/2020 21:54:26

Over 20 or so years ago I bought a pair of then current version of these Vertex VJ400 110 mm wide by 180 mm opening vices from Rotagrip **LINK** . About £70 - £80 each then. Imperial dimensions too!

I have been very, very happy with them. The extra opening capacity compared to a normal machine vice has been very useful. Far as I can see they are the economy version of a hydraulic vice. A screw being cheaper.

Great thing is that they have three position for the nut allowing them to offer a much wider range of opening than the usual style of machine vice. Simply pull a pin out, wind the nut along and replace it to change positions. Openings are 60 mm, 120 mm and 180 mm nominal. Possibly not quite as rigid as a good Kurt or quality Acculoc copy but I've had no significant issues although, for obvious reasons you do have to be a bit more careful at full extension, I use the 60 & 120 mm positions mostly.

Initially used on a mill of similar size to Ians' Amadeal but I was always goring to move up to a Bridgeport eventually (5 years later actually) so I grabbed two at the show offer price.

For really serious holding I have a (now) excellent 6" jaw Abwood which cost very little and responded well to a careful re-furb. Comes out about once every 5 years or so! Its heavy.

Clive

Thread: Cut a transverse tapered hole (Unimat milling column)
11/01/2020 19:10:00

Quick footnote about the 2 mm depth quoted for the RS cutter.

These cutters are primarily sold for adjusting the sizes of holes to make them a little larger when the original drilling wasn't quite big enough. The thicker the material the greater the difference in size between the big end and little end. Obviously too much difference and the fit of whatever goes in the hole becomes rather iffy. Variation over 2 mm thickness is considered small enough not to be a worry in the intended applications which, generally, are not exactly precision.

Many years ago I was told that using such on material up to 10 gauge - 1/8 " (3mm), was fine but it was advisable to go in from both sides on thicker material. Which reduced hole size variation. The ones I used had a screwdriver style handle drilled for a tommy bar. Quite effective as I recall matters but fairly hard work in thicker steel and needing a good deal of care to keep straight. But I never used them enough to nail the technique down.

If doing a longer hole step drilling first to ease the load sounds sensible.

Clive

11/01/2020 12:14:57

Do you have to match the standard taper and use the standard taper bolt or can you simply make your own taper and bolt for the milling column. If making your own pair is acceptable perhaps the taper on a small diameter plain cone cut bit will be close enough to work. Given the hole a matching taper on the bolt shouldn't be too hard to do as you can use the cutter as a gauge.

Perhaps something like this **LINK** would make a suitable hole.

From an engineering perspective I can't see the exact taper as being especially significant.

Clive

Thread: Bottled Gas Suppliers
10/01/2020 15:19:46

As ever its the quality of the folk supplying the stuff rather than the stuff that matters. First find good helpful suppliers, then decide what to get.

I'm sure you have seen it but AirLiquide guidance here **LINK** . That said I'd want to see something strapped to the car or van to keep the bottles upright. Most especially acetylene.

I flogged through the suppliers & prices thing about 9 months back. Primarily MiG gas for me and a mate but I did look at the other types too just in case I went O-A. Bottom line seemed to be that rented works out cheaper at around 2 bottles or more a year, rent free below 1 in 2 years. In between its a wash, need to figure out best for your use.

Unless you have a grandfathered deal like my mate has with BoC which is well cheap. Way he tells the story Y (I think) size bottles got unpopular and BoC had a lot cluttering up the depots so they rented them out cheaply to low users figuring that it was better to get some money from other folk storing them than having to pay for depot storage! By my maths he gets the bottles just about free taking into account delivery.

When doing comparisons check out the filled capacity of the bottles. Some brands are at lower pressures. HobbyWeld seem to be at the lower end.

The MiG I lucked into on E-Bay came with an Albee cylinder and there is a supplier 6 miles down the road so I'm happy although the gas comes out a bit more expensive than HobbyWeld (12 miles down the road). Rent free Albee cylinders are more expensive than plain ones suppliers. For MiG difference is roughly the price of a decent regulator so, as I didn't have a regulator it mattered not. The Albee regulator does have a flow set valve built in which is nice and saves on getting a flow meter.

Frankly if your AirLiquide branch always has Albee cylinders in stock and will efficiently do a rent-free changeover in person I'd be inclined to stay with them. I can put up with rude/sarcastic if visiting once a year or so. Just so long as the job gets done like now. Messing with an account tho' it's up against the wall, hand round their throat with feet dangling time!

Clive

Thread: Looking to buy a better toolpost
06/01/2020 15:15:48
Posted by John Reese on 05/01/2020 23:58:27:

The Warco style requires the Vs be precisely spaced and parallel for repeatability. I doubt the Asian manufacturers will maintain the level of precision to allow you to buy replacement tool holders that fit properly.

Its a common misconception that Dickson style toolposts and holders need super precise spacing of the Vees to work properly. Line contact of the toolholder on either the two outer faces or the two inner faces of the post Vees is sufficient to ensure stability so small errors of spacing, in grinding machine context at least, don't matter. It is important that they be parallel and of essentially equal depth. Not intrinsically difficult given a sensible production set up. As ever design for production and inherent mutual accuracy from the, ideally simple, set-up is important if precision is to be achieved at a sensible price. The Dickson Vees are good from that aspect.

More likely to get trouble from the locking mechanism. Depending on how you count there are between 7 and 11 places where tolerance errors can build up. Functionally all that matters is that the Tee slot in the holder shall be at the right distance from the toolpost for the tongue to draw the holder hard back against the toolpost when the internal "cam" is close to pullback dead centre. The closer to centre it is the higher the pull back force but if it goes just past force will be lost.

In a practical world thats where errors are most likely to be found. If I had a poorly locking system I'd be playing about with shims temporarily glued on the locking tongue to sort out the actual errors then set about re-making the tongue assembly to functional dimensions. The unit is basically a spindle with a vertical hole through it and a flat end so not hard to make. In principle I see no reason why the tongue couldn't be simply cut off and re-fitted with a countersunk headed allen screw and spacer to get it in the right place. Practice might be a little more challenging.

Took some quick measurements off my size 2 Dickson and Rapid Tipo A posts to get some idea of industrial standards. The Dickson locking handle has 130° total movement giving about 60 thou, 1.5 mm, tongue pull back; call it 0.5 thou, 0.012 mm, per degree. The Rapid has 160° movement giving around 100 thou, 2.5 mm, pull back; call it 0.6 thou, 0.016 mm per degree. Assuming around 10° variation in spindle position at lock is acceptable that suggests something of the order of 4 thou, 0.1 mm, variation in Tee slot position can be coped with. All very handwaving (in the real world there are tangents involved!) but, if it seems like the locking spindle is turning past dead centre, it might well be worth experimenting with a 2 thou, 0.05 mm, shim under the locking tongue. Only good for trials but informative if you do consider re-making the innards. My motley collection of holders from several brands show no readily noticeable variation in locking handle position suggesting that the professional products hold total errors down around the 0.5 thou, 0.01 mm, range when mixed and matched.

Clive

Thread: Timesaver lapping compound quandary
06/01/2020 10:09:45

Best to ask the folk who make the stuff. There is a contact form on the website **LINK**. Unfortunately the link to the information booklet download doesn't work (for me).

My understanding was that the yellow soft metal version breaks down more quickly to avoid over-lapping softer materials. Which makes sense considering that the basic process is to keep going until the material is "used up" and turns to slurry.

However its reported that the green ferrous metal version has been used to finish lap old style babbit big end, crankshaft et al bearings in situ by simply adding a prescribed quantity to the oil and running the motor off load. There are references suggesting this was a normal process for marine and other big engine rebuilders. Not a bodge shop or field expedient.

Which suggests it probably doesn't really matter so long as you keep an eye on what you are doing.

Clive

Thread: Ebay being clogged up by certain sellers
05/01/2020 22:03:37

I've build up my own exclusion lists for my saved searches and save them as a text file which I open before browsing E-Bay. Before perusing the results of the basic search I open the advanced options and cut and paste the relevant line into the text box with the "exclude seller" tick box checked. Then run the search again to get results sans dross. UK only is my default for saved searches anyway.

As a Mac user I keep the exclusion list in TextEdit but I'm sure Windows and Linux folk have something equally effective.

Obviously every time I hit a new dross source I copy the selelr and add to my list.

My current pet peeve is that E-Bay changes have broken the sniper program I use (JB Bidwatcher). Whats worse it seems the guy who wrote it has given up supporting it so i've either got to find something else or get used to hangigna round until its almost the end of the auction. What I loved about the sniper was being able to set a rationally decided maximum value and just leave it to do its thing. If I won the auction, fine, if not someone else paid over the odds.

Clive

Thread: Looking to buy a better toolpost
05/01/2020 20:23:18

As Cabinet Enforcer says probably better to verify that the Dickson clone is properly made and everything is fitting properly first. Standard checks are pretty straightforward although they are more usually employed to verify that different makers interpretation of the Dickson design are actually fully compatible.

1) Locking lever travel from released to lock should be around 90°. Much more and it will be going past centre so lock force is reduced, much less and it won't come up to full lock. On real Dickson and industrial standard clones full release is around 10° or so past centre in the release direction so, judging by mine, effective travel is likely to be of the order of 80°- 85°. Look at the holding tongue movement without a toolholder fitted and it should be clear whats going on. Mark the full lock angle of the handle with a holder fitted first.

2) Height adjustment screw not perpendicular.

3) Collar in the height adjuster a poor fit in locking shaft groove.

4) Height adjusting collar too large so it tries to push the holder away from the post.

3, 4, and 5 should be obvious if you look closely from the side.

5) Registration Vees misaligned or wrong centre distance. Offer up the holder by hand and check with engineers blue. So long as one side on each male and female Vee has a decent fit over most of its length it should work fine. (There are limits to the precision that is practical at an affordable price.) Partial fit usually indicates something is at an angle. Fit on two sides of one Vee only means it will almost certainly be insufficiently stable although a small error may well pull up OK. A couple of mine are imperfect when tested but perform fine.

6) Grot in the body. Very common, my industrial standard ones need cleaning out every year. Seem to be a magnet for itsy bitsy teensy weeny swarf.

7) Poor fit, contact or other errors in the actuating cam system. Inexpensive clones sometimes aren't as well de-burred as you'd ideally like. Easy enough to pop the actuator out by setting at the right angle and pushing the locking tongue back against the spring so the shaft can be withdrawn. Sorry I can't tell you the right angle. My hands know what to do but the brain gets confused so I just do it and try not to think.

8) Mounting technique. Proper way to use a Dickson is to push the toolholder into place against the toolpost Vees then lock it up. Relying on the tongue to pull things up square is bad practice as there is considerable friction invoked. It can also bend the adjuster stud. ("I used to be a toolmaker" Paul got an earful for doing that to one of mine where brand X and Rigid Tipo were a bit short on clearances.)

Old Mart makes an excellent point about the simple reliability of the four, two in practice, way block. Especially if you are primarily a carbide tool user so the cutting edge height doesn't get altered by re-sharpening.

I'm always surprised that lathe makers, or a canny aftermarket guy, didn't come up with a simple quick change system for loaded toolblocks. Especially as so many of the higher end machines had a face ratchet alignment system under the standard fourway post. Quick release by interrupted thread, 1/3 rd turn locking cam et al would seem relatively easy for a manufacturer to arrange. If I ever figure a simple to make in the home shop version my Dicksons / Rapids will be history. Hmm 18 holders and 3 S2 posts to sell. I'll be rich!

Clive

05/01/2020 18:57:03

Even without a stop pin in the hole it shouldn't move with the sort of cuts that lathe can manage.

Verify that the slide surface and toolpost base are actually flat and that the toolpost stud is perpendicular to the topslide. Use a bit of engineers blue to see where its actually touching. Shouldn't be an issue with a fairly new machine but I've seen enough older machines with such problems to always check.

Centre stud out of perpendicular is the easy one to miss. Doesn't take terribly serious knock to put them out a little. If the hole in the centre of the toolpost has minimal clearance the toolpost will never sit down well. First time I saw that stud issue I didn't notice until we were getting desperate and decided to wind the stud out to re-machine the topslide top as the blue showed poor contact. Whereupon it wobbled as it turned and we said "Ahah, gotcha".

I usually put a thin aluminium shim underneath to give better grip. Other folk prefer thin card but that needs changing every year as it tends to pick up oil.

Clive

Thread: Alexander master toolmaker
05/01/2020 09:41:15

Further to Johns comment about single screw adjusters for taper gibs its important that the screw head is a nice fit in the slot and that the head is exactly perpendicular to the slot. The head is usually quite large in relation to the thread so they can be bent by careless and hamfisted folk.

Moving OT for a moment.

Had the jackpot on a Chinee import mill pushing 20 years ago. Slot too wide, screw shank bent and threaded hole in the slide out of line. An object lesson in how an insecure taper gib can turn into an evil minded self adjusting wedge. I imagine the minimum wage guy on the assembly bench did what he had to to to get it all together despite the misaligned thread. Once I'd identified the problem and re-made the necessary parts it worked very well indeed. A good machine spoilt by a seemingly trivial error.

Clive

Thread: Odd sleeve
05/01/2020 09:26:37

Having sorted out what it is the next question must be how did they make a sufficiently accurate D section taper back in those days?

Obviously you can't ream it to size and broaching sounds difficult. I'd cut the side off a proper taper and weld or silver solder the flat on but thats very home shop guy.

Clive

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