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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: How on earth do I do this
15/02/2016 00:03:33

Um, could be.

I have a mini lathe, where the Cross and Topsldes have 20tpi feedscrews, but the leadscrew seems to be 1.5mm pitch.

Have been told that one manufacturer does this, and supplies at least two UK importers, so this might be a third.

Try using a DTI to measure the travel for one complete rotation of the handle, after taking out the backlash. That should show the pitch of the feedscrews.

At least this should tell you the travel per division on the scale, in whichever unit you want to work

Howard

Thread: surface rust on lathe ways
14/02/2016 23:44:46

+1 for Scotchbrite nylon scourers. The different colours signify different grades. I think that the dark green used in the kitchen are the hardest. They will remove rust, but unlikely to remove much metal, look how the material wears out with use in the kit chen on ceramics. We used to use them in industry for cleaning dirty or rusted surfaces. Would advise using oil rather than paraffine (kerosene), it can absorb water, so that you would plant the seeds of more rust.

For iron or steels to rust there must be water and oxygen present. You won't keep out the oxygen, unless you vacuum pack the lathe, so once clean, seal out the water with oil.

In my previous shop, when cold, the oil on the bedways of my Myford would turn milky as it emulsified with the moisture, so had be wiped off and replaced after use. Keep the atmosphere as dry, as possible, and above the dew point, (I switch on a 240 volt, 60watt tubular heater when the weather is cold, in a well insulated shop, in UK, and VERY rarely see any rust). If you are in a high humidity location, the problem is greater, and you may even need to use a dehumidifier.

Do not heat the shop with any combustion heater, (Woodburner, gas fire, liquid fuel heater) since these all produce moisture in operation; and Carbon Monoxide which will not do you any good.

If you want to ventilate, have the vents at floor level.  Moist air is heavier than dry.

Howard

Edited By Howard Lewis on 14/02/2016 23:45:53

Thread: Centering a Chuck to a Rotary Table..
14/02/2016 23:22:31

If you want to be precise clamp down the table, and site a mag base beside it, with a DTI on it.

Clock a piece of round bar, held in the chuck and keep adjusting the position of the chuck to get minimimum run out.

If you can mount the chuck on an arbor (2 or 3MT Arbors are available with Myford thread/register, maybe Boxford also?), this will make centering on the RT an absolute doddle.

You could even make up your own, if you think that you will need to do this in the future.

Once centered on the RT, then you use the DTI and round bar to centre the R T under the Mill or Drill spindle.

HTH

Howard

Thread: Picking one UK show to attend..
14/02/2016 23:12:27

Hi Rob!

Hope that you have a splendid time over here.

One word of warning, some of our motorways are prone to delays, especially around the morning and evening rush hours, (M25 seems like that all day every day, rarely without a jam up, so allow PLENTY of time for the return to Heathrow)

Although the speed limit is 70mph on motorways and dual carriageways, single lanes out of town usually 60, but slower in some places. There are also variable limits posted on electronic signs, or on posts approaching roadworks. On all roads there are speed cameras, and unmarked as well as marked police cars, so stick to the limits posted. (I have even seen cameras hidden behind signs apologising for the delay at roadworks!)

Your spending money is for fun, not traffic fines.

Watch out for the drink/drive laws, if visiting pubs! You can be pulled over and tested for the slightest moving offence, if the officer feels so inclined. No doubt US is similar!

The suggestions given for show and itinerary are all good. We have huge wealth of Engineering Heritage, all over the land. Your problem will be deciding on which ones to visit.

You will find UK Model Engineers friendly and interested, so have a marvelous vacation.

Howard

Thread: Just joined
13/02/2016 19:03:50

Welcome! You will find a lot of good advice here, and a lot of banter.

For what my advice is worth, and this is only repeating what many have said before.

Decide on what you want to make (Remember that you may eventually want to do other bigger and more complicated things)

Search through the Forum for comments on the sort of machine that you have in mind to buy (Don't be surprised at widely differing views on the same machine - depends upon individual experiences, BEFORE you buy it). You will find some excellent folk and advice here

And remember what I was told, "You can do small work on a big machine, but not the other way round", so if in doubt go for a bit larger than you first think. Almost certainly, you will find yourself making attachments / accessories / gadgets that ,make life easier, or allow you to do things that seemed impossible at first.

Having said that, splendid work has been done on machines that are supposedly too small!

Lastly, ENJOY YOURSELF!

Howard

Thread: BH600G Fine Feed Help
13/02/2016 18:49:43

If you are worried about repositioning the stud, it is only a M8 tapping, and a matching hole in the sheet metal cover, large enough to take the fitting.

It might be worth making a knurled metal knob, before hand, just in case, like me, you destroy the composite one.

Howard

Thread: Retired American living in France with a new toy
13/02/2016 18:42:14

Coming in late, others have raised the possibility of the brushes needing replacement.

(My big Bosch pistol drill ran perfectly, and then next time refused to start. New brushes and as good as new! Fortunately, the comm was undamaged)

Also, during your checks with the meter, did you check continuity across the windings on EVERY commutator segment? If one winding was open circuit, it would have trouble starting, on that position, and be down on power. I have even heard a motor with a burned out winding knock once it was set running.

Just a thought, as a non electrician.

Howard

Thread: Turning a wheel eccentric to the motor drive without gears/belts
13/02/2016 18:01:28

The Whitworth Quick Return mechanism was used as the drive to ram of shapers.

If a varying speed of rotation is needed and IF space is available, why not use the Whitworth Quick Return Mechanism (shown earlier) and couple it to a Con Rod and Crank to change the linear motion into rotary?

Or have I missed something, in the objective?

Howard

Thread: BH600G Fine Feed Help
13/02/2016 17:30:21

My lathe is a Engineers ToolRoom BL12 /24, which other than having metric leadscrews, dual dials, and different paintwork, is virtually the same as the BH600.

To produce a finer feed rate, I made a 80T gear to replace the 40T on the input to the Norton box.

From memory, the gears are 1.5 Mod.

This then means that the closing arrangements for the Gear Cover have to be modified.

On my lathe, sadly, to remove the closure fitment from the cover I had to destroy the composite knob.

(Fortunately, a suitable replacement was available,) A new tapping had to made into the Norton gearbox casting, and a fresh hole drilled in the Gear Cover, to match. But it works. With the gear train set to 40T : 127/120T : 80T, and the gearbox set to to E 8, my calculations suggest a feed rate of 0.00225"/rev.

The tumbler gears were noisy on mine, so eventually, they were replaced by nylon ones. If memory is correct, the two cost £41 from Davall Gears!

Obviously, if the gears are meshed too tightly, they will be noisy, not to mention being more prone to wear. Backlash is set by trapping a piece of paper in each mesh, before tightening the fixings. This should give about 0.003" of backlash, after the paper has been removed.

The big compound gear is, I suspect, the source of the ringing. The holes in it SHOULD reduce sound radiation, but I wonder if filling the holes with lead would be a means of deadening the sound further? Because this would increase the inertia, and so possibly reduce sped variation, this may also contribute to noise reduction.

Lubricating the gears with a really thick grease helps to lessen the noise, very slightly. (I was given some specialised gear lubricant which is really gooey!)

Hope that this may be of some help.

Howard

Thread: Rotary table / indexing (help)
22/01/2016 17:30:28

Nick,

Your Rotary Table looks like my Vertex HV6.

The Handbook that comes with it contains a parts list, and brief instructions on how to use it for dividing, and a table, (Inside the back cover), giving the Plates to use and the number of turns and holes, for each set of divisions, upto 99.

But not all division numbers are available (such as 28,51,52,53,59,61,64,67,68,71,73,76,77, 79,83,84,85,88,89,91,92,and 97)

Mine has a 90:1 worm/wheel ratio, so for 8 equally spaced holes the table gives

' A' plate, 20 hole circle, (The outermost one in this case) 11 turns and 2 holes of the crank handle, between each drilled hole.

If you have not got the "Operation and Service Manual" for the table, send me a PM, and I'll see what I can do to help.

Are you UK based, if so, whereabouts?

A recent tip was to make up two pegs to be a good fit in the holes, and short enough to be clear of the peg in the handle, as it rotates, to fit BEHIND the fingers, so that if you catch the fingers while turning the handle, they do not move to lose your starting position. As you need to move the fingers round, the pegs are moved to retain their position. (Obviously, make sure that the screw clamping the two fingers together is tight)

I've just done this, and it is useful.

Howard

Thread: supercharged V12 2 stroke
10/01/2016 17:44:45

Can only be in awe of Dean's design and machining skills, his persistence and to marvel at the end result.

Words are scarcely adequate to describe my admiration. SUPERB!

And it look as if there is a lot more to follow! I shall watch this space, (or whatever is set aside for the successors)

Howard

Thread: Change Gears on Myford ML7R
10/01/2016 16:48:44

To ensure just a little backlash, when meshing gears, I run a piece of paper into the mesh, and then tighten the fixings. (IF it needs to be said, as a general rule, no gears should be run without backlash. Yes, there are special set ups to eliminate backlash, such as split gears pushed in opposite directions by springs, and the like)

On my lathe it is a messy job, since everything is kept covered in grease or gear lube, to minimise wear

Howard

Thread: Neat cutting oil. (recommendation)
10/01/2016 15:40:34

Thought that Tric had been outlawed, YEARS ago, because of its dangers. Was an excellent degreaser, but dangerous!

Having said that, much the same can be applied to almost any of the Hydrocarbon/Halogen degreasing agents.

Most certainly do not smoke near them, or breathe in the vapour. Not good for the skin either; well they are degreasing agents!

Howard

Thread: DAB workshop reception
10/01/2016 15:29:17

being purely a mechanical engineer, I would agree, (on the basis of the picture) with the likelihood of the Antenna input being 300 ohm, and with the need to match the antenna and connecting cable impedance to that of the set, to maximise power transfer.

Radio hams usually opt for "as high as possible" for antenna positioning, and in alignment with the transmitter.

At 225MHz the elements of a yagi are going to be pretty short, (digital TV is around 240 / 250 MHz from memory,

So your radio antenna is going to be only a bit larger. A folded dipole is likely be even smaller, end to end.

The data already posted plus a bit of calculation should allow you make reasonable antenna, and position it for best reception.

Having said all this, I very rarely switch on the FM radio in my shop! Too busy metal mangling!

Howard

Thread: Threaded end mills on an ML7
10/01/2016 15:09:03

If you are tight on space, use a Morse Taper Collet.

If you wish to hold other sizes of End Mill, Slotting Drill, or workpiece, my advice would be to buy a holder for ER collet holder, and a set of collets. They will definitely come in handy in the future, for holding tools or round workpieces.

Howard

Thread: Xmas present
10/01/2016 14:56:10

You could do worse than to buy ER collets, holders, and chucks, if you do not already have: a plunger DTI, a Finger clock, and a Magnetic base.

You will find a use for all of these at some time in the future.

Howard

Thread: Repton RT1 Ball Turning Tool
03/01/2016 17:38:13

Seeing the comment about clearing/fouling the toolpost, the handle on mine did foul the top of my fourway toolpost. But since the end has been bent slightly, it no longer does! End of problem.

Howard

Thread: Use By/ Best Before Dates
03/01/2016 17:14:17

Noticed recently that even sealed tins (Peas, broad beans etc) have "Use By" dates on them!

Many years ago, meat (the contents of a tin retrieved from Shackleton's expedition, was eaten, inadvertently, by the lab assistant. He thought that it was his lunch, and reputedly said that it tasted good.

In a long life, I have only met one tin that was "blown", and that was a few weeks ago.

Several years ago, drank a bottle of french beer that was two years out of date, without any obvious ill effects, and am still here to pester all the readers.

Can you understand my cynicism about "Best Before" and "Use By" dates?

Howard

Thread: Question: mounting slitting saw
03/01/2016 16:00:39

As an Apprentice, (at a world renowned maker of engines, cars and gas turbines) we were told NEVER to use a key with a slitting saw. One of my fellows forgot, and the flying bits of a six inch dia saw just missed several of us, the other half was still rotating on the arbor.

If it jams, it slips, but does not become dangerous shrapnel!

Howard

Thread: Merry Christmas to one and all!
24/12/2015 13:01:51

Yes,

A Merry Christmas and a Happy New year to all Forum members.

We can only wish for Peace on Earth, when we think of the various conflicts.

And spare a thought, at least, for the poor souls who have suffered flooding in Cumbria.

Howard

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