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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: Mounting a new chuck
18/09/2018 00:48:38

Thank You Bandersnatch! You have taken my meaning exactly

I did not want Mark, or anyone else, to think that fitting a 3 jaw Chuck to a Backplate would lead to absolute concentricity, of a piece of round bar clamped in a 3 Jaw. Which is why, if two, or more, diameters have be concentric, they should be turned in succession, without disturbing the Chuck in any way. My technique, for right or wrong, would be largest / larger diameter first, than the next decreasing diameter(s)

The best that can be achieved, in my view, is as you say, turn the Backplate, on the Mandrel, to be a snug fit in the Chuck, fix the Chuck to the Backplate, and then start making swarf

Howard

Thread: new boy
18/09/2018 00:32:46

Thought that i had posted a reply to N D I Y

Single Phase, 240 volt

As far as i know it is a Little John, painted green, (Although the Headstock end, with QCGB looks like the Five Inch) The Saddle from memory, also looks like the Five Inch, but the Cross Slide carried a Four Way Toolpost, while the Top Slide which could replace it carried a single tool holder. (I made up a Four Way Toolpost for him, to fit onto the Top Slide so that he could change tools more quickly, and turn short tapers if needed). Three and Four Jaw Chucks, Tailstock Drill Chuck, Centres (i think - haven't spent much time with it for a while). I made him a Handwheel for the Mandrel, to help when cutting threads upto a shoulder, and a Centre Height Gauge.

No details as yet of what Change Gears or tooling is in the cupboards of the stand.

Will update as info becomes available, (They are heavily into packing at the moment!)

Howard

Thread: colchester student 1800 apron no drive
17/09/2018 23:02:41

So have you found the source of the problem? And more importantly, solved it?

Put us out of our misery!

Howard

Thread: Carriage slipping
17/09/2018 22:30:32

Looks like a mini lathe of some marque.

Have you checked that the (probably plastic) gears are: 1) Intact - No broken teeth or torn keyway)

2) That the keys are present in all the gears from Mandrel to the Leadscrew, (otherwise you are relying solely upon friction to provide to drive to either the Leadscrew, or the pinion and the Saddle)

If the geartrain includes a compound gear as an Idler, there should be a key long enough to unite both gears, and similarly, the key on the Leadscrew should be long enough for both the gear on the leadscrew and the spacer

Without the spacer, the gear could float and not drive continuously. The gears should mesh over their full width.

With regard to ,meshing, there should be just enough backlash on each mesh to allow a strip of paper to pass through, no more and no less. (The Banjo and the Idler stud(s) are all clamped up properly, are they?)

One of the gears is not running eccentric is it?

DAMAGE reported: ANYTHING bent, Leadscrew, shaft in the Saddle, (might account for the "slipping on the rack" Not the tumbler reverse?

As suggested, maybe you need to ask if anyone local to you would be preared to come and have a look to see where the problem lies, and what might be done to solve it.

Howard

Thread: New member
17/09/2018 22:10:49

It only stops in the kitchen? Sometimes the bedroom floor sparkles, but that tends to make my ears burn!

Strange that she would pay extra for a top that sparkles like mine. (maybe the permanence is what costs?)

Howard

Thread: Mounting a new chuck
17/09/2018 22:05:51

If the Backplate OD runs true when on the Mandrel, and is a snug fit in the Chuck, I would spot through and use the P & B long bolts to hold the two together.

With the best will in the world, a three jaw is never going to hold work absolutely concentric. The only way to get two or more diasmeters concentric is to turn them without disturbing the work in the Chuck, before parting off. Teaching Granny to suck eggs!

Howard

Thread: fire warning
17/09/2018 21:59:13

daveb

Don't trifle with such matters!

Howard

Thread: new boy
17/09/2018 21:51:45

Funny the mention of a Raglan. A friend of mine is moving house and has decided that the lathe, sadly has to go.

Any ideas on how much it would be worth please?

Howard

Thread: Owner of cast iron seeks knowledge
17/09/2018 21:45:31

Welcome aboard!

You will certainly gets plenty of advice ande xperience, as you probably, already know.

If you give your location, it is possible that some kind soul may even offer physical help when needed.

Howard.

Thread: Arc
15/09/2018 22:35:34

Why not relaunch the brand next March as "Arc Pound Trade" instead of "Eurotrade"?

Although we never had the Euro as a currency in Britain.

Apologies, Ketan, just my weird sense of humour.

Howard

Thread: Under-type Wagon vs Over type
15/09/2018 22:26:18

With regard to speed, the full scale Sentinels, especially the S4 and S6 on Pneumatic tyres were FAST (despite the legal max speed being 20 mph) so a speed of 10 mph for a model might well be in keeping!

Howard

Thread: fire warning
15/09/2018 22:18:07

A while ago, I read of an incident with a bench grinder. The owner's son had used it to grind some wood (No comment!) but when owner used it there was a "whoosh" as the sparks from the metal set off the wood dust.

At school, we were warned of the risk of solvent vapours, such as ether, rolling along the bench from point of use to where there was a naked flame, with predictable consequences.

One of the dangers in a Flour Mill, is that of the dust exploding, (flour is a hydrocarbon, cellulose, so if mixed in the right proportions with air, becomes an explosive mixture)

At various times, experiments have been carried out to run a diesel engine on pulverised coal, working on just that premise. (Thought to be possibility for large main propulsion marine engines) Not too long ago, one of the U S A Railroads tried injecting coal slurry instead of gas oil to run the engines in locos. The problem was the abrasion of the parts of the injection system, (pumps, fuel lines and injectors).

And, given the right conditions, an internal combustion engine can suffer a crankcase explosion, with dramatic, if not lethal, results. One of my former bosses told of crankcase doors weighing 50kg or more being thrown across the shop!

Surprising easy to set oneself, or the surroundings alight, unintentionally.

Howard

Thread: Website Clock Times
15/09/2018 21:57:00

Just to send this even further off topic,

Can anyone please explain why the audio attached to the video of "The Last Night of the Proms" is not in sync with the Radio soundtrack?

Trying to watch, whilst listening on a Hi Fi set up was, to say the least, so confusing that I reverted to the poorer TV audio.

Is it that one has to be delayed by a second or so, so that it is no longer a "Live" broadcast; or is it that processing the video data takes longer than the straight audio of the radio broadcast?

Howard

Thread: Backlash Allowances for Gears
15/09/2018 21:38:00

Gears should never be run without backlash (If, for some reason, you MUST have Zero backlash, then you need two thinner gears pushed in opposite directions by one or more springs).

The easy way to set backlash is to adjust each mesh so that it just nips a piece of paper (about 0.003" or 0.075mm in round figures thick).

Howard

Edited By Howard Lewis on 15/09/2018 21:38:26

Thread: Mounting a new chuck
15/09/2018 21:15:53

Hopefully. the Backjplate O D runs true when on the Mandrel? Is it screwed onto the mandrel, or

If the Chuck has the facility to be retained by long bolts from the front, surely the easy way is to fit the Chuck to the backplate, and spot through to drill and tap for each hole.

Other tappings in the Backplate would be needed for the setscrews, or studs that retain the Chuck onto the Flange on the Mandrel, unless it is a screwed nose on the Mandrel.

Howard

Thread: What do you call this type of chuck?
15/09/2018 21:08:46

When I bought mine, (secondhand) they were described as "Bell Chuck). Don't see a lot of use, but invaluable when the need is there. As part of the deal came some male versions. So washers can be held either on the OD or the ID.

Howard

Thread: Myford Super 7 Mounting Blocks
09/09/2018 14:52:49

In the past, on more than one occasion, two of us have moved a ML7. But it can be unwieldy, if you do not take into account the offset weight of the motor.

Positioning the Tailstock and the saddle will help to balance the lathe in one plane.

If you lift it with a sling, be careful about putting a sling behind the chuck. You are putting part of the weight onto the Headstock bearings.

My inclination would be to disturb as little as possible, even trying to move the lathe with the raising blocks still in place.

Howard

Thread: Cost of mini lathes
09/09/2018 14:44:58

You can buy a used machine, or a new one.

Depending on which mini lathe you choose, The importer will include different items in the package. One may include 3 and 4 Chucks, whilst another importer may only include a 3 jaw. Another importer may include steadies, or a drill chuck and centres in the package.

Some may still offer brushed motors (and of varying powers) whilst others may have the newer brushless motors.

A used machine may no longer have all the items with which it came when new.

(My secondhand mini lathe came without the spanners and Allen Keys, but did have a brand new 4 jaw chuck, a Steady, a set of cutting tools, and the manual, as part of the deal).

Afterthought:

Ensure that all the change wheels are there, and undamaged if they are plastic!  You can buy replacements for any damaged or missing ones, but take into account the likely cost when negotiating the price.

If buying a secondhand machine, do check its condition and see it in operation. Since they are variable speed, it is not unknown to damage the control boards by incorrect operation. The manual is important. Incorrect operation can ruin the control board, which can be pricey to replace!

Check the specification and package on offer as well as the price!

Howard

Edited By Howard Lewis on 09/09/2018 14:47:18

Thread: Carriage slipping
09/09/2018 14:33:31

What lathe are you using? Knowing this will help.

Were you using the Leadscrew to provide the power traverse, or the Rack and Pinion?

If the machine is what is normally meant by "mini lathe" then the power traverse will be provided by the Leadscrew, there being no other form of power to the Saddle.

If the Forward / Neutral /Rreverse selector for the feed fully engaged? The spring loaded handle should engage with one of three indents, to lock it in the Forward / Neutral / Reverse position.:

Being a mini lathe, it is likely that the gears are plastic, rather than metal. Are all the teeth intact? One or damaged or missing teeth on one or more of the gears may the problem.

If this is the case, replacement gears should be available from one of the importers.

If this is the case, you MUST specify the machine, since some machines use 3mm keys and keyways, whilst others use 4mm, and the bore may be different.

This assumes that the gears are all correctly meshed. Firstly, the banjo should be set so that the gears are correctly meshed. Normally it should just be possible for the gears to rotate with a piece of paper passing through where each pair mesh. Excessive backlash may allow the gears to "slip". This is likely to damage both the gears.

If the pinion is "slipping" on the rack, presumably, you cannot apply the feed by moving the Saddle with the Handwheel. If this is the case then the Pinion is probably not engaging the Rack properly, or the gears within the saddle are damaged (probably missing teeth) but less likely since these are usually metal.

If the saddle moves using the Handwheel, but "slips" under power traverse via the Leadscrew, then either the Half Nuts are closing completely, for some reason, or there is a problem in the gear train driving the Leadscrew. The half nuts may be damaged, in which case they will, need to be replaced. Again, it is presumed that the le3adscrew is clean and not clogged with swarf, which would prevent proper engagement of the half nuts.

When the "slip" occurs, does the Leadscrew stop rotating? If so, the problem lies in the drive to the Leadscrew.

There should be a key in the Gear providing the drive to the Leadscrew.

All the gears should have full face engagement. If not, then it is possible that a spacer is missing, allowing a gear to move endways and disengage.

There should be a key uniting the gears in any compound gear gear in the gear train.

The tumbler reverse gears under the mandrel should be engaging fully, whichever direction is selected, and be intact and undamaged .

The Pinion on the Mandrel should have a key, so that the drive is taken positively, without slipping.

Hope that this is helpful in finding the source of the problem.

Howard

Thread: A matter of trust...
04/09/2018 20:48:24

If you want to make a new point for the scriber, you could sacrifice a good quality 2.5mm twist drill, (or even a broken one) and sharpen the shortened shank to a point.

It works well for me!

Howard

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