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Member postings for Howard Lewis

Here is a list of all the postings Howard Lewis has made in our forums. Click on a thread name to jump to the thread.

Thread: Flexispeed meteor-II lathe Cross-Slide / lead-screw†specs.
20/01/2021 21:54:02

Maybe the camera thread, which has been 1/4 BSW since LONG before I was born, (and 3/8 BSW for larger cameras. STILL used on professioinal tripods today ) is why the ISO UNC standard is so sloppy that "one size fits all"?

We could screw UNC bolts, IF we had any, into BSW tappings, but had to retap UNC tappings to use the BSW bolts so beloved of our Chief Engineer at the time.

You think I'm a Luddite?

He made us change all the 5/16 UNF propshaft bolts with Nyloc nuts to 5/16 BSF with castellated nuts and split pins before a new vehicle was put into service. Because the holes were out of line, they slackened in service and the depots the had to tighten, redrill and repin before the MOT inspector got to see them!.

Howard

Thread: Vertex (V4?) Rotary Table
20/01/2021 21:38:12

Thank You Michael.

Haven't read it all through, but it seems that my guess of 19 and 20 was what was used originally.

At CAV, in the mid 60s, we regarded Simms Motor Units as being a poor relation with lower standards, Certainly what i saw of the Minimec vs the NN type, in the 70s, it was a more cheaply made device. And in my experience, of much lower quality. I had to make a couple of unannounced visits to Finchley to sort out problems that should never have happened.

Hopefully Martyn will be able to make up a set of parts that will perform as required to put bhis car back on the road again.

Howard.

Edited By Howard Lewis on 20/01/2021 21:39:22

Thread: Drilling crankshaft hole
20/01/2021 20:42:16

Even if you do not have a mill, all is not lost.

With a lot of care, and some filing it ought to be possible to set up the casting in a 4 jaw, and machine a datum face. (As already said ) the base would be my choice. That dtum can then be used for many subsequent machining operations.

With a sutably sized packing piece, the casting can be faced (flycut? )and set up forto be centre drilled and drilled/reamed for the crankshaft . By using the reamer and the reamed hole to align the casting again, the other end of the crankshaft bore can then be flycut to face it.

Every machined face/ bore can be used to aid alignment for other machining operations.

Bonne Chance

Howard.

Edited By Howard Lewis on 20/01/2021 21:28:48

Thread: Sheffield here
20/01/2021 20:30:03

Welcome aboard.

You are really well equipped.

Hopefully before too long you will be able to find and attend a local Model Engineering Club to meet with felloe enthusiasts.

Howard

Thread: New Member Andrew
20/01/2021 20:26:09

Hello Andrew, and Welcome.

If anyone can come forward with an engine hoist (Folding crane ) and some strong enough slings, with a little help it should be possible to load the machines into a van or pick up truck (sheet and tie down and wedge for the journey ). Boxes of spares / material etc can be used as dunnage to reduce the risk of movement. Ratchet straps can be invaluable for this sort of work

Even without lockdown, I am too far away, and my crane will not fit into my downsized car, to be able come and help. So can only make hopefully helpful noises from afar.

A lathe like a Myford ML7 can be lifted and moved by two men,although the offset motor makes it a little unwieldy.

A milling machine will, need more care, and may well demand the use of a crane.

Whatever you are moving, you will know the need to take care not to injure yourselves or the machinery.

A lathe can balance better by positioning the Tailstock and saddle along the bed.

A Mill is best moved with the the sling around the head, so that the centre of gravity is below the slinging point.

No doubt there will be plenty of round bar available that can be used as rollers to move a mill along the floor. A lathe is best placed on a sturdy platform to moved in similar fashion.

If yiu sling bthe lathe,take care not to crush leadscrew or any other shaft. It may be frowned upon by many but sometimes a sling behind the chuck and Tailstock end of the bed is a safe way to lift it.

When you get set up, making the 10V will give you the experience, skill, and confidence to start work on completing the Triple. That would be a splendid memorial to your Great Uncle!

Good luck with the move and setting up your shop.

Howard

Thread: Vertex (V4?) Rotary Table
20/01/2021 20:06:33

Aside from chasing microns, the essential thing is that the driving and driven portions of the coupling are a close fit to the intermediate differential vernier centre part.

Given the age of the car, it is unlikely that the original parts were the sort of air tight fit that is now being promoted. These were mass produced parts in an age where machines were probably not capable of the precision that we now expect of an industrial machine.

In the 1930s, car production was much more labour intensive, and relied upon the skill of those assembling parts.

Many true fitters would have been involved.

It was said that Freddy Dixon could add 5 mph to the top speed of a Riley just by stripping and reassembling the rear axle!

Bear in mind that the mounting holes for the magneto will be clearance, so there will be latitude on both linear and angular alignment, no matter how much care is exercised in assembly.

Despite the low power outputs, some torsionals will find their way through into the drive, so some "bedding in" aka wear will be inevitable.

Why else would Martyn be in need of replacing the originals? Surely not just cosmetics

Howard

Edited By Howard Lewis on 20/01/2021 20:07:53

Thread: Flexispeed meteor-II lathe Cross-Slide / lead-screw†specs.
20/01/2021 19:47:34

From personal experience, I can say that a BSW bolt into UNC will not go.

Our Chief Engineer would not countenance anything other than BSW and BSF. When we came across UNC threads in Clayton Dewandre unloader valves the tappings had to be tapped out to BSW for the bolts that we had in stock

If the Leadscrew is UNC then it should be cleaned up with a UNC Die. Ideally the die should be adjusted using a good quality UNC bolt as a gauge.

If the BSW Tap goes into the leadscrew nut, either the nut bis worn, or someone has already put a BSW Tap through it.

Before buying a UNC die, try a good quality UNC nut on the thread.

Butb if the nut has already been modified to BSW, you might as well set up the Dies on a good BSW bolt and modify the thread to match the nut.

Not an ideal situation, but you have to live with what is there, unless you can obtain or make prototype replacements.

Howard

Thread: Benchtop lathe with power cross feed, looking to buy
20/01/2021 18:19:17

Being a fully paid up Luddite, I use Imperial most of the time, but is just me.

My BL12-24 lathe is actually Metric, but dual dialled. so gives, hopefully, the best of both worlds.

Having heard of so many people having problems, possibly self made, with control boards and DC motors, my inclination would be to bite the bullet and go for the VFD and more powerful 3 phase motor.

The chip tray will be useful, essential even. Worth having a metal splashback behind the lathe, to keep the wall clean. It will wipe more easily than painted ply, or chipboard wall.

You could make your own bespoke stand so that the lathe is at a height that suits you. It can be tiring to be bending over a lathe that is too low.

Hopefully, you will be using the lathe for a long while, so it will be worth spending extra money to get something closest to your ideal.

You can spend a lot of time thinking "Oh, IF only, at the time, I'd..... "

HTH

Howard

.

Thread: Vertex (V4?) Rotary Table
20/01/2021 17:59:11

Since the three parts each need a radius in the bottom of each "pocket" maybe the RT could be used in horizontal mode, with a ball ended end mill of an appropriate size (If not, then setting the RT in vertical mode, and grinding and stoning a "special" flycutter will be needed. )

Assumes use of a vertical mill.

Once the "pockets" have been cut, the RT can be used in vertical mode, and the tops of the "teeth" rounded,by use of another bespoke hollow flycutter.

Two actually, one for higher number of pockets, and another for the lower number. So possibly four in total, male and female.

HTH

Precision is relative. At one time, mines were drained by pumps and steam engines made before the micrometer had been invented, or screw threads standardised.

We now use, for our hobby, machines of precision beyond the wildest dreams of those artisans.

Interchangeability of parts only came in the latter part of the 19th century, from arms manufacture.

For our hobby, we now use machines of greater precision and accuracy than the wildest dreams of those artisans.

Howard

Thread: Advice for surface finishing
20/01/2021 12:53:17

FWIW,

You may get a better finish using a HSS tool, with a small radius stoned on the edge.

The larger the radius, the greater the risk of chatter, so you have to find a balance between speed, depth of cut and feed rate that suits the material, tool and machine in use.

Obviously the tool needs to be sharp.

Carbide tips tend not to be sharp. The intention is that when run at high speed the tool rubs and generates heat which softens the material.

Having said that, I have produced a good finish with a carbide tip by running at low speed with a very shallow depth of cut, with neat cutting oil applied.

Possibly the good finish is the result of burnishing rather than actual cutting.

It goes without saying that the tool must be mounted on the centreline of the work.

If you have a Tangential Turning Tool the standard HSS toolbit supplied has a radius on the edge.

For a finishing cut, a minimal depth of cut may be beneficial, (as Jason's 0.001" cut ), and the feed rate needs to be low. (You are effectively cutting a screw thread of minimal depth and pitch. The finishing cut should remove the "thread" left by the roughing cut

HTH

Howard

Thread: Surface/ Marking out plates
20/01/2021 09:59:45

+ 1 for a lapping plate.

Howard

Thread: Benchtop lathe with power cross feed, looking to buy
19/01/2021 13:11:12

If you have a lathe, MANY possibilities are available to you.

The latest Sherline looks to be quite a machine, which explains the price!

It is smaller, and in some ways less complicated, than what the OP is hankering after, but should be capable of some very good work for its size.

Howard

Thread: Myford ML7 4 way tool holder
19/01/2021 13:01:27

In the search for rigidity, I would rather reduce the tool holder shank, rather than the Toolpost.

Hopefully, the spring and pawl for the ratchet have not been lost?

A non engineer friend was twice sold Myford toolposts without the spring, pawl or ratchet wheel!

Howard

Thread: Water pump for spindle cooling
19/01/2021 12:51:32

Antifreeze also contains inhibitors which will reduce, if not entirely eliminate, corrosion, so will be a benefit on two fronts.

Howard.

Thread: Marine Engine Flywheel Fixing
19/01/2021 12:48:06

It is quite common for flywheels to be located to the flange by either a dowel, for location rather than a keyway, ( to avoid a stress raiser ) or by fitted bolts, with one displaced so that the wheel will only fit in one angular position.

In marine practice, the shaft and propeller inertia would probably act as a flywheel to reduce cyclic irregularity, probably aided by the hydraulic damping of any torsionals.

With the likely length of the shaft, and the inertia of the prop, the natural frequency would tend to be low.

Howard

Thread: Benchtop lathe with power cross feed, looking to buy
19/01/2021 10:36:07

You could place an ad in the "wanted" section of the classifieds on here.

But remember that the Warco BH600 and the Engineers ToolRoom BL12 - 24 are the same machine in different colour schemes.

Warco "Used machines" site is "sold out".

T'internet doesn't seem to show up any of those, used.

Howard

Thread: 920 lathe noise
18/01/2021 18:34:10

Thanks for letting us know.

Glad that it was a simple problem with zero cost / trouble solution.

You may have made life and sleep easier for someone else who has similar problems.

Howard

Thread: bolts
18/01/2021 18:26:04

Absolutely right Nigel.

Do you know of a good proof reader?

Howard

Thread: Chuck fitment to dividing head
18/01/2021 18:21:33

It could be that the thread forms differ, or even worse, the pitch.

Reading lathes UK, it looks as if the Mandrel thread is 1.5 x 8 tpi USF, so would expect to be 60 degree thread form.

If the Dividing Head has a 1.5 x 8 tpi WHIT form (55 degree ) thread, that might account for your problem.

Male Whit form threads do not screw easily into Unified female threads, even of the same pitch; they jam!.

I would check the thread on the Dividing head with thread gauges, to establish the thread pitch and form.

Howard

Thread: bolts
18/01/2021 17:55:07

M2 Coarse has a 0.4 mm pitch, and M2 Fine has a 0.25 mm pitch, So both too fine for a pitch between 0.6 and 0.7

Taking the coward's way out would it be feasible to drill and tap out to

8 BA? 2.2 mm OD, 1.68 mm core 0.43 mm pitch Tapping drill 1.85 mm

7 BA 2.5 mm OD, 1.92 mm core 0.48 mm pitch Tapping drill 2.1 mm (Non preferred size )

6 BA is 2.8 mm OD, 2.16 mm core, 0.53 mm pitch Tapping drill 2.35 mm

Howard

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