Member postings for Muzzer

Hi MEiT

Mine's a Taiwanese BP clone too which also has the NMTB30 spindle. I've been able to find holders at reasonable cost and runout (doubtless some luck involved there!). Have you seen my quick change tool holder? Works a treat - one of the best tools I've made for it.

Murray

"Wish i knew how to rotate the pictures !"

If you saw my rant a couple of months back, you'd know that the only solution I found was to get rid of Windows 8 / 8.1. Luckily I am now back on W7 and much better for it. And I refuse to bu**er about with 3rd party programs just because some smart 4rse at Microsoft decided to change something. I even paid £40 extra to have W7 on a new laptop rather than W8.1

There.

I set my digital calipers to the final dimension I want, then zero the display. Then I take a skim of the work piece with the cross slide dial set to zero and measure the resulting actual diameter of the work with the calipers. The indicated distance tells me directly how much more diameter I need to remove. When the work piece is reduced to the point that the calipers display zero, I'm there.

My Bantam cross slide dial measures directly in mm diameter increments, so I can now dial in the required additional cut directly. If I'm feeling paranoid, I can take several cuts and confirm that I am approaching the final diameter from above by using the calipers after each cut.

I normally work in mm but if the diameter is imperial, I set the required imperial diameter on the calipers, zero it and then swap over to metric display.

If I had a "radius" indicating dial, I'd have to take my chances at halving the number between the caliper display and the cross slide dial. Halving numbers is something I can still usually manage but it doesn't arise with the Bantam.

In North Vancouver it was illegal to put bins out until the morning of collection due to bear activity, so in the summer you'd need to keep 2 weeks worth of leftovers in the bin in the garage (= workshop!). Not something that would encourage workshop time. The Insinkerator was a handy appliance. I once got a large turkey carcass down it before it tripped the thermal cutout but they are almost bullet proof.

It wasn't all scaremongering either - the week before we moved out, the neighbours left their garage door open by mistake and their wheelie bin got emptied out all over the garage floor by one. Raccoons, coyotes or even cougars wouldn't have been able to do that. They quite often came down the street and ended up in houses, swimming pools etc. They rarely attack people, which is lucky as you can't outrun them or simply climb a tree.

The foxes in central Cambridge seem to be completely tame. I was sitting in a queue of traffic on Madingley Road a few years back when a fox walked along the pavement down the row of waiting cars, as cool as a cucumber. I could have reached out and touched it if I'd been in the passenger seat. Reynard!

Murray

Chris

No, I bought a 3mm Korloy Sawman indexable parting tool as you can see from this album. Works really well. I use a few hundred rpm and power feed with coolant and it doesn't flinch. I'd forgotten that I made a Youtube video of it.

I wouldn't go back to HSS now except for very narrow grooving. I also wouldn't try to operate it upside down! I am going to get some "H01" grade inserts for parting aluminium and light alloys - although it parts these OK with the steel cutting inserts, the material sometimes doesn't clear fully, resulting in snagging and poor finish. Cutwel sell single inserts online.

I also have a Korloy KGT tool which not only parts and grooves but is also designed for normal turning operations. I've got inserts for both steel and light alloys and it's pretty darned good.

I have to admit I often use an indexable boring bar for both internal and external turning. The internal operation is pretty obvious - but for external turning I move the tool behind the centre line and reverse the machine. In this way, when you have the top slide at 45 degrees for chamfering, you can use the same setting for both internal and external chamfers. That avoids having to keep swinging the topslide back and forth. You need to swap out the boring bar for a proper turning tool when you have more than an inch or two of overhang or if you want to make proper heavy cuts.

When using the machine in both directions like this I like to sanity check that the power feed is the correct direction. I always try to use the power feed and feed stops where possible so I can get a decent finish and a reasonable rate of material removal.

Murray

Edited By Muzzer on 12/12/2014 20:50:33

I can't see my Bantam from the armchair here but logically the topslide should have half the scale numbering of the cross slide, given that it spends much (most) of its time not perpendicular to the axis. Can anyone confirm on this or a similar machine?

Murray

In N America they even have different sized ES lampholders to the ones we get here. I suppose that's to prevent you screwing in the wrong voltage bulbs. Having just returned to the UK from there with some acquisitions, I am now faced with more different ES sizes than you can point a stick at - at least 4 at last count. At least the bayonet holder doesn't have quite as many sizes....

Merry

On the subject of upside down parting tools, there aren't many lathes that are designed to withstand a lifting of the slides (including the saddle) by the cutting force, so I concluded that for my Bantam at least, any rear-mounted parting tool should be operated with the lathe in reverse and the tool not inverted.

If you look at the assembly drawing / exploded parts list for your machine, you will see what arrangement is used to restrain the saddle against this vertical (upwards) movement. It's usually fairly minimal and primarily intended for locking the saddle at a single point. Unless you have this saddle lock adjuster tightly nipped up (which isn't ideal in terms of wear), there has to be vertical slop in there and the horizontal location by the bed Vee's will also suffer from any such vertical movement .

On the cross slide, there is a firm and direct contact between the horizontal underside faces of the slide and its base in the "normal" direction. With cutting forces in the reverse (upward) direction, the slide is instead held by the angled gibs with some slop ie much less well defined and rigid.

I can only assume that in some cases, the additional slop and springiness resulting from running the tool upside down actually helps to reduce the likelihood of judder, most likely combined with light cuts. However, if you were asked to demonstrate exactly how the tool position is positively defined / constrained, I suspect you'd struggle. Generally speaking, rigidity and control seem to be the safest way to prevent "rubber pants" moments during heavy parting operations.

Murray

The Colchester Bantam also reads directly in terms of diameter reduction. Once I realised it is fitted with metric leadscrews and dials on the cross slide and topslide (but has an imperial main leadscrew and gearbox!), I was able to see that the dials indicate direct 0.1mm (major) and 0.02mm (minor) increments. I was confused for quite a while by the mixed units, although it seems to be a common situation on Bantams, many of which were supplied to schools.

I measure the actual diameter with a digital caliper and dial in the required final cut directly. Works as intended.

Murray

Edited By Muzzer on 12/12/2014 12:32:34

Thinwall tubing mainly.

For the avoidance of further confusion, when joining copper to copper using copper rods (eg Sifsilcopper 985) as Ron is, the process is "welding". When joining similar or dissimilar metals eg steel with copper (or other similar "bronze" alloy) rods, the process is "brazing", whether the heat source is an arc or otherwise. The tipsandtricks page deals with brazing.

And if you try using electrical copper wire, copper plumbing tube or other non-oxygen-free filler, you will not have a happy experience!

Murray

Lee

Sounds like a case of "physician heal thyself", except that even the physician's tools are in need of repair. One step at a time. Good luck!

Murray

Can you fit it in the lathe (in the gap), with the saw in the spindle? That way you'd have coolant and the right speed, both of which you need. The teeth on those hole saws are very fine and fill up with swarf very quickly so you need to do more pecking than a nervous hen(?), clearing the teeth out with a brush as you go.

I had some success notching pipes this way (with the pipes clamped to a vice in the top slide) and having used a hole saw on some 1/4" plate in the drill press, I'd be tempted to use the lathe next time if I didn't have a decent mill with a back gear and coolant.

Murray

As I'm not a model builder, I have no experience of soldering model boilers but from my experience in plumbing and electronics manufacture, I'd be wanting to use the lead / tin rather than lead free (ie almost entirely tin) solder.

Apart from lead free solder having a higher melting point, it has lower surface tension and doesn't benefit from the more gradual solidification you get with lead itself - and leaded solders. It doesn't wet and fill gaps as easily and when it flows it's a lot more mobile. You certainly wouldn't be able to "wipe" it with a moleskin like the traditional plumbers used to for instance.

Although plumbers are required to use lead free solder for pipework that is carrying drinking water (similarly for electronics), presumably you can still find leaded solder if you look. If I didn't have some already I'd be looking to get some before tackling a job like this.

Murray

Obviously there's nothing magical about a tangential toolholder that somehow allows one set of cutting angles to work for all materials. If you were to try machining brass with a tool that is ground for light alloys, you'd want to be wearing your best rubber pants. It's possible you could get away with it if you take tiny cuts and have your slides nicely nipped up but why would you bother? With a tangential tool, you can have a toolbit ground for brass etc (zero top rake) and one for light alloys (perhaps 20 degrees or so) and swap them over in seconds.

Indexable tooling is pretty rugged and forgiving but even so, they have quite different cutting angles according to the material being machined. Same with HSS twist drills for brass (slow or zero helix) and light alloy (fast helix).

I don't have a tangential tool myself, so perhaps I'm not qualified to comment!

Murray

Alibaba is really aimed at the trade ie minimum order quantities can be a problem. The retail sister website is Ali Express and the prices are similar but it's geared up for one-off purchases and includes a form of payment protection in case you have a problem with delivery etc. It works rather like ebay and the sellers are very careful to maintain a good feedback rating, as without that they won't be able to sell to people like us. You only complete the purchase once you have received the goods and are happy with them. If not, you can either get a refund or a replacement. Many of the products include free shipping and it's amazing how quickly this stuff turns up.

I bought quite a few parts recently from AliExpress for my milling machine CNC conversion including pulleys, belts, ballscrews, bearings, proximity switches, MPG pendant etc and it was a good experience. I even had the ballscrews machined to my drawings for $5 extra which saved me a fair bit of work (threads, keyways etc) - and they did a good job. A set of bearings got lost in the post but they sent a free replacement set. The originals turned up a week later which was a bonus.

Murray

My first lathe was a Portass model "S" which was (still is) 3" x 12" or so and was easy to manhandle by a 15 year old (as I was at the time), so I was able to overhaul, modify, paint and mount it on a bench top myself. It gave me excellent service for quite a few years and I did all sorts of jobs on it, as is the true "model engineer way". The other candidate at the time was a massive (probably 7" centre height) Drummond with integrated drive. I always shudder when I think back to when I was on the verge of buying it as it would have been a mistake, lovely machine though it was.

As you and others say, it depends what you are expecting to be turning. My Bantam is sometimes not big enough for my needs but it's a lot better than an ML7 for my particular purposes. For others, a Myford is fine, if a little expensive perhaps. The other issue with going for a larger machine apart from sheer weight is the cost of accessories. If you double the centre height, you will be needing chucks etc that weigh something like 8 times as much (2 cubed) and the cost isn't going to be far behind, possibly higher as you are getting into professional territory.

One of the key considerations should be the availability (popularity) of compatible accessories. The great advantage of my Bridgeport clone milling machine is that the basic design seems to be common to the majority of medium sized machines and so there is a vast range of parts and accessories available. It may have been satisfying to preserve a "special" antique such as the large Drummond but it would have been very expensive and frustrating in the long run.

Of course, in the interests of science, the correct answer is to keep buying different sized machines to cover all the bases. And keep expanding your workshop to accommodate them as it would be sacrilege to sell any of them. That's certainly the way I see it!

Murray

Hi Howard

The crank case is shared by all the cylinders in this design, so there is no possibility of using crankcase scavenging to charge the cylinder, as is common in small (<1 litre) 2-stroke engines. And there is little chance of accommodating 12 tuned exhaust systems to achieve the exhaust scavenging that is seen on a normal bike engine for instance. Without assistance, it's not going to be possible to get mixture into the cylinders.

Most of the large diesels mentioned have defined, mechanical exhaust (and inlet) valve arrangements, whether poppet valves (like most marine and rail diesels) or sleeves (opposed piston engines) or ports (for the inlets). However, the volumetric efficiency of a large marine diesel without a blower of some form would be pretty miserable. The thermodynamic efficiency of a diesel engine (and gasoline) is improved by supercharging and unlike a gasoline engine, there is no issue with detonation which limits the compression ratio and ultimately the maximum cylinder size of gasoline engines.

Whether you call it scavenging, charging, supercharging, blowing or whatever, this fine little engine will need some form of positive charging if it is ever to fire up. It's a pragmatic and sensible realisation. Besides, it gives us armchair experts something to pontificate about!

I'm fascinated by Dean's incredible work here. I couldn't achieve anything in the same class as this and I'm marveling at the progress. Keep it up Dean - hope your health doesn't keep you out of the workshop too much! Looking forward to each update and hopefully some engine noises soon.

Merry

Somebody must have gone out and spent millions on this gear originally, even in this "also ran" outfit, yet in my experience of liquidations it will go for something like 10% of what was paid. There's something a little distasteful to me about the sheer extravagance of this sector. I love engines and motor sport but they burn through money like confetti.

As F1 offices go, this is shabby. The McLaren offices (probably the other extreme admittedly) are completely free of anything other than the monitors and keyboards. No ornaments, books, food, mugs, pencils, plants, no nothing. Cold and clinical, devoid of personality, no clue what sort of business is carried out there. You could eat your dinner off the floor. I found visiting there a scary experience although the architecture was surreal. If you wanted anything to eat or drink, even a cup of tea, you had to walk over to the cafeteria. They need someone like JS to bring them down to earth!

These machine tools(?) are a bizarre sight, alongside the CMM machines and giant surface plates. Perhaps they belong to the gardener! I was expecting proper CNC machining centres etc. Clearly a pretty low key operation with any proper machining being farmed out to local machine shops.

Merry

I had my Bridgeport clone milling machine (1 tonne) for over a year before my wife noticed it, despite having to walk past it each day to get to her car. I was staggered. Seriously, she asked me where it came from and when I'd got it. I suspect John's colour theory may have some merit and for future reference it was that nice machine tool blue grey.

However, you can be pretty certain that small and expensive items will be spotted from 50 yards. The rotary table was noticed immediately (despite being an outrageously good bargain and coincidentally paid in cash), doubtless due to the brown (unauthorised) paint. I'm sure there's a lesson in there somewhere although that suggests some degree of logic that probably doesn't exist.

Merry