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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: Wanted - Someone to make some screws
25/10/2021 15:52:27

In my experience, Sterling keep a wide range of types. Got to be worth visiting to ask the question, and seeing what they can offer

Howard

Thread: Wandering mill table
25/10/2021 15:42:21

If you grip the ends of the table, and can wobble it back and forth, the gibs are not set correctly.

I would expect the gibs to be trapezoidal in section, Wide faces at an angle to matc h the dovetails, but with the narrow faces horizontal, and not fouling on any other part, with the adjusting screws engaging in the dimples.

Ideally, the gibs should be adjusted with the leadscrew disengaged. (Removed? )

If the table gibs can be adjusted so that it moves smoothly, but with absolutely minmial slack, but it tightens when the leadscrew is fitted you need to investigate the leadscrew and the nut, Possibly as suggested the nut is out of place in some plane.

HTH

Howard

Thread: Wanted - Someone to make some screws
25/10/2021 15:22:55

Have you tried Sterling Nut and Bolt in Royce Road, Peterborough? They have a minimum order of £5 + VAT, so your 4 screws will cost you £6.

Might be worth a phone call or better a visit, especially if you can take examples.

Howard

Thread: Rust Protection
25/10/2021 15:19:44

It would be worth buying /making some duckboards to keep your feet off the cold concrete floor.

When Toys R Us were in business, they sold rubber mats 1 metre square. Cut in half, provided two metres of matting in front of a lathe or milling machine.

Sit down before you look at the price of mats from industrial suppliers, like Cromwell.

But look around for alternatives from cheaper sources.

Amazon do some Wellmax 60 x 40 cm barrier mats for £11.99 with free delivery on the first order.

Have a look on Google to see what is available.

Howard

Thread: Wanted - Someone to make some screws
25/10/2021 15:09:16

Reducing length, or OD of a M6 SCH screw is fairly easy, in most cases.

How about some details of what you are looking for as a end product?

I am in Peterborough, if that is any help.

Send me a PM?

Howard

Thread: Rust Protection
25/10/2021 13:30:38

Concrete garages are renowned for "sweating".

May I suggest, if there is enough space, to fix 50 mm battens to the walls and fill the space with glass fibre behind 12 mm ply?

Give the door similar treatment if you possibly can. A metal door is NO insulator.

Paint the ply white and the place will seem much lighter.

If you can apply the same treatment to the ceiling, you will find the place much cosier, and almost devoid of condensation and the rust problems that it causes.

My shop, in East Anglia, is only 10'9" x 6'9" external, 19mm cladding outside, glass fibre between 50 mm frames, walls and ceiling.

The only uninsulated bit is the 3/4" ply floor standing on 8 x 2 bearers protected on three sides, on concrete slabs.

A 2 Kw fan heater rarely runs for more than 15 minutes before the thermostat operates. Then it runs, perhaps for 5 minutes every 30 -40 minutes.

When it is frosty, a 60W tubular heater under the bench produces a bench warm to the touch afetr about 24 hours.

Rust is almost never seen, despite no extra oiling / protection.

Howard.

Thread: Chemical Etching of Glass
25/10/2021 13:13:12

Ammonium Bifluoride? So uses the Flouride ions to do the etching, presumably.

Still the thought of a 12 y o handling it seems a bit dodgy, but maybe I'm just windy!

Howard

Thread: Ferrous, facing, HSS tool geometry
25/10/2021 13:04:03

It is important that the tool has sufficient clearances. Tool, little and it rubs and overheats. Too much and the tool ,is weak and wears quickly, if it does not break.

Maybe the good surface finish resulted from too little clearance so that the tool rubbed and burnished the work, until the edge failed, giving the poor finish towards the centre.

5 - 10 degrees will suffice for most jobs, it is rarely necessary to be exact, unless dealing with something more exotic that mild steel.

Sometimes a lower speed and some lubrication will give an improved surface finish.

A steady, fairly slow feed rate will provide a good finish in most cases. Without a power cross feed, that entails learning how to use both hands to turn the handwheel mat a reasonably steady rate. (One of the first things that we were taught in the Training School ) No more than 0.004" (0.10 mm ) per rev is what to aim for.

For the next try, regrind the tool to give clearances, and try again, on mild steel.

HTH

Howard

If that works, then have a go at the silver steel.

Thread: Correct Drill Bit For 3/8 UNC Tap
24/10/2021 11:46:53

Zeus Charts give the tapping drill for 3/8 x 16 UNC as:8 mm (BSI Recommended ) or 5/16 as an alternative.

If you have not got a set; well worth investing in. Still using mine bought in 1958! .

Always a source of reference for threads and many other things, (BA, BSW, BSF, BSP, ANC, ANF, UNF, UNC, Metric Coarse, Metric Fine, Fits, Metal Bending Allowances, Hardness Comparisons, Co ordinates for equally spaced holes, Morse taper dimensions, Mathematical tables. )

Howard

Thread: Ferrous, facing, HSS tool geometry
23/10/2021 18:28:01

Ian Bradley's "The Amateur's Workshop" gives angles for grinding tools, as will many other books on the basics of lathework..

For most materials, 5 to 10 degree clearance angles seem to suffice.

Possibly with a small radius stoned all the way down the front edge, to improve the finish. The rad must go all the way down the edge, or the tool might rub.

Brass seems to be quite happy with minimal Top rake.

It could be argued that the radius should be a little larger than the feed rate per rev, so that the radii cut overlap.

For most of what we do, because of the materials that we use, it probably will not matter if the clearance is a degree or two away from the "ideal"

Maybe, for facing a knife tool ground as a left hand tool and mounted parallel to the axis would do the job.

For light cuts, an ordinary right hand knife tool presented to the work to provide a clearance angle of five degrees to the face would probably perform satisfactorily for light cuts. Deep cuts risk chatter because of the width of the chip being produced.

The Diamond tangential tool has a variety of clearance angles, because of the way in which the tool is oriented, and quite atop rake, but it functions very well, and only needs one face grinding, the other angles being produced by the holder.

Probably more important is keeping things as rigid as possible, so that the angles ground on the tool are those at which the tool is consistently presented to the work.

Some may disagree with some or all of the above. What matters is what works best for you and your machine.

Howard

Thread: Myford ml7 "parting off"and "max working size"
23/10/2021 18:03:28

The parting tool needs to be as rigid as possible, so minimise the overhang. My HSS blade is adjusted for minimum protrusion from the holder .

If parting off large diameters, I rig a gravity feed to a home made needle valve and jet held on a small magnetic post on the Cross Slide, so that the blade gets a steady drip, or flow of soluble oil.

The feed comes from a plastic "pump" bottle on a shelf above the lathe, with the feed tube being a length of plastic screen washer pipe pushed onto the spout from the pump. The pump is handy to prime the system and start the soluble oil syphoning down the tube to the workpiece.

Howard

Thread: Collets for Myford tailstock
23/10/2021 17:52:55

I tap under power (Admittedly using the "Jog" function of the VFD contyrol box )

A Mandrel Handle comes into it's own on lathes lacking this facility, and allows the operator to be aware of the torque being applied, before the Tap breaks!.

Having used a Tailstock Sliding Die holder, I made up an ER25 collet holder for taps of various sizes.

A ME 40 tpi thread will not withstand trying to pull a heavy Tailstock along the be when the Tap is held in a drill chuck.A sliding Tap holder imposes minimal load on the Tap to move it forward into the work.

Torque reaction is taken by a stud screwed into the body, which rests against the side of the front toolpost.

It has the advantage, that if anything jams, the Tap ,slips in the collet rather than breaking. If it is just things getting tight, the Tap can be left in the work, the tap holder removed and with the Tap, hopefully now correctly aligned, the job can be finished using an ordinary Tap Wrench.

Howard

Thread: Spacing of buttons for making involute cutters
23/10/2021 17:37:44

There was an article in M E dated 2nd September 1994 which dealt with gear cutting and in which there were some a table giving button sizes and spacing, which may be of help.

Howard

Thread: Advice from the photographers.
22/10/2021 20:16:31

If the intent is to store the slide image as an electronic image, you could use a slide / negative scanner., rather than the camera

The cheapest is about £15 and is likely to produce a file of about 4 - 5 Mb.

This should be adequate for many purposes, but possibly not if projected onto a 6' screen.

Howard

Thread: Clattering Backgears
22/10/2021 20:11:01

Idle thoughts.

If the Back Gear is engaged by rotating eccentric bushes around the shaft, can the travel be increased to reduce the backlash between the gears on the Back Gear shaft and the Mandrel?

Ideally, backlash should be such that sheet of paper (about 0.003" / 0.076 mm ) just passes through the mesh.

If the bushes are worn, rather than the shaft, could you make new, and fit, closer fitting bushes?

If it is the changewheeels that are noisy, again, setting the backlash should reduce the noise.

Excess backlash is likely to produce clatter, especially when lightly loaded, and driven by a single phase motor.

Too little or no backlash is likely to produce a groaning noise rather than a clatter.

This assumes that all the chnagewheels are correct for the lathe, i e correct DP and Pressure Angle to mesh with the driving gear on the Mandrel..

The noise is caused by a slight variation in drive speed, and the driving belts may cause this. Cheap / worn belts sometimes are swollen around the join, and this can cause problems.

HTH

Howard

Thread: Lathe query.
22/10/2021 12:16:02

As Robert says, start checking for mechanical problems. BUT start at one end and work your way through.

Is the motor free to turn?

Then check through the drive train to the Chuck to see if anything is locked / seized.

It might only be an overlength bolt, an overtightened clamp, or a seized bearing.

It could even be that back gear is engaged without freeing the driven pulley from the mandrel.preventing rotation, or defect in the gear selection mechanism all owing two speeds to be engaged at the same time..

Once a mechanical problem has been eliminated then start the same logical sequence on the electrics, starting at the power feed switch, and following through to the motor feed cables..

Power OFF, use a multi meter, of course

Howard

Thread: From where I might be able to source some 1300 micron (1.3mm) mild steel sheet?
22/10/2021 12:07:43

If you want an easy release from the permanent magnet a shim of copper may do what you want. I believe that the pole, piece of a solenoid had a thin copper coating to prevent the armature sticking to the pole piece.after the current had been removed

Shim brass might do the same job..

Howard

Thread: Myford ml7 "parting off"and "max working size"
22/10/2021 11:50:49

Forgot to say that the largest item machined was a brake disc, which JUST fitted into the gap

My parting tool is 3/32" ( 2.38 mm ) HSS.

Tried a 2 mm wide carbide tip parting tool in the front toolpost and had TERRIBLE dig ins. So bad that the holder was damaged and the tips fell out!

Reverted to the reliable HSS in the rear post ever since.

Howard

22/10/2021 11:46:15

My ML7 had a long Cross Slide, so i made a Rear Toolpost, and mounted the parting tool on it, INVERTED, being careful to keep the cutting edge on centre height. It also has / had NO Top Rake.

Gave no trouble, as long as I kept a slow steady feed.

The same tool, mounted in a shop made four way rear toolpost , on a larger lathe, works so well that I now feel brave enough to part off under power!

HTH

Howard

Thread: warco 220
22/10/2021 08:43:16

At 125 Kg it is going to be too heavy for lifting by just two people.

If you use an engine crane to lift the machine, it looks as if the Sling would need to go behind a firmly clamped Tailstock.

I don't like suggesting it, but the sling looks as it it will need to be behind the chuck.

Positioning the Saddle can be used to help balance the machine fairly level.

Alternatively. for some lathes, (including my 300Kg machine ) it is suggested to fix a clamp to the bed, suitably positioned for balance, and hook then crane onto that.

It looks to be a deep bed casting, so should be reasonably free of twist.

You have hours if not years of pleasure ahead of you!

Howard

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