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Member postings for Oily Rag

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

Thread: Taking Leave
19/09/2020 18:30:23

Andrew,

I join in the praise given above for your depth of knowledge and experience. Your posts are always a delight to read being well written and concise. I shall be sorry not to read your valuable inputs in future. Get back when you feel the need after earning some wonga!

Stay safe and drop by every now and then.

Regards,

Martin

Thread: Scaling back forum activity
09/09/2020 23:22:07

Barrie.

Being an 'occasional dipper' member of the forum I will be sad to see you becoming, like me, an occasional visitor. I have always found your posts to have been succinct and to the point, unlike a lot of the great unwashed masses!

Stay safe and best of luck in all you do.

Martin

Thread: Plain lathe gearing for 'bastard' metric thread
21/08/2020 16:02:03

Thank you everyone who responded.

The confusing part about the leadscrew pitch is that it gives the formulae and finalises the tpi by a multiplication of 16, the tumbler gear assembly does give a 2:1 ratio as mentioned by Martin Connelly; this rather than my incorrect assumption that it was achieved via the back gear, which I accept increases torque available by slowing the spindle speed rather than affecting anything else (a Simpson moment! Doh!!).

As the job is mounted in a 4 jaw and not wishing to break it all down, having taken all bar the finishing cuts to clean, up I was loathe to break it down for a trial cut. Then it struck me that I could mount a 'Sharpie' fine point felt pen on the toolpost and 'scribe' a trial thread on the component. Sure enough the thread was wrong - I had transposed the C/D gear wheels and managed to get a finer pitch thread! Getting them the right way around gave the correct pitch.

Thank you again everyone who responded - it helps to be able to discuss issues like this when you are a one man in a shed with only those who know how to bake delicious cakes in the household!

20/08/2020 21:59:42

Hi All,

Just need a confirmation from the members here that what I have geared the plain lathe drop gears will produce the thread I expect.

A little background is that the lathe is a Raglan Little John. This has an 8 tpi leadscrew and in backgear this equates to a 16 tpi leadscrew. for those that do not know the Little John the drop gears are arranged as A/B x X/Y x C/D. A/B gears are fixed centres and must add to 90, likewise X/Y are also fixed centres and must add to 96, whilst C/D can be a floating arrangement able to accommodate a fairly wide range of gear combinations.

The X/Y pairing are listed as 48 x 48 for English threads and 52 x 44 for metric threads.

I am looking to cut a 1.66 p Schaublin buttress thread for a tool holder for my mill. Previously I have used a set up with a 51 tooth gear but for some reason the workshop gremlins have hidden it. In desperation I sat down and tried to formulate the gearing using standard gears. I came up with the following:-

A = 45, B = 45, ~ C = 45, D = 40, ~ X = 44, Y = 52 - in each case it is Driver/Driven. with compounding of B~X and Y~C

this gives the gear ratios as A/B = 1.0; C/D = 1.125; X/Y = 0.846154

this gives 15.2307 tpi, or 1.6676p

I arrived at this combination by juggling the gear set up for 18 tpi which was given as A/B = 45/45, C/D = 32/36 and with the X/Y meshing pair set for imperial at 48/48. by using the metric tooth counts at X/Y (52/44) BUT by reversing them I got the reduction necessary to give the final tpi/pitch required. Note that for reasons outside my control the 36/32 C/D pairing fouls the gear boss so I increased the tooth count to 45/40 to maintain the ratiometrics (9/8 as an improper fraction)

Will it work or have I missed something basic?

Thread: Measuring tilt angles
14/08/2020 15:14:36

Making a W20 toolholder for a 3" shell mill. The angle of the nose on the W20 is listed by Schaublin as 8 deg +/- 5' (i.e less than 0.1 degree) - the accuracy required is due to the shortness of the taper probably.

Set it up by milling a 4 degree taper on a 2" bar, then clamped it into the 4 jaw, making sure it was running true, set it 'square' with a T square off the bed of the lathe and then adjusted the compound slide by clocking back and forth along the taper to give less than 0.0001" run out.

Turned the taper, blued it and it fitted the socket with excellent marking.

As I mentioned in my earlier reply the angle was set on the mill by using the swivel table by reading off the scribed angle and gently adjusted by using a Munro made gunlaying double opposed bubble clinometer Recently calibrated to a level of confidence of 10" of arc. with accuracy at 4 degrees being recorded as +/- 'zero'.

Best single piece of kit I own!

Thread: Aciera F3
14/08/2020 10:55:43

Hi Barry

Glad that was of help. Give me a few days, as I'm in the middle of a job and the machine is not looking her best at the moment covered in swarf, and I'll photograph the platten shield, X table lock and arrangements for you to give you an idea of how it should look.

I can strip the parts off and give you the dimensions. Might be possible to replicate the platted shield, but it is a casting. The X clamp bears down on the top edge of the table in a non mounting position i.e it is away from the component mount area.

They are superb machines which are rightly highly rated, with a full set of accessories there is not a lot that you cannot make with them.

Have you got the exploded spares list view? If not I can copy tht leterature for you as well.

Best Regards,

Martin

Thread: Large left hand tap
13/08/2020 15:08:46

I must admit I am at a bit of a loss as to what you are actually threading, are you referring to threading the wheel carriers? If so why? surely the wheel carrier will sit on the plain portion of the spindle and then the wheel will be clamped with a LH nut pulling up to a suitable washer which covers the wheel - not forgetting the paper washer interposed between washer and grinding wheel.

Most English grinder spindles used either 1/2" or 5/8" BSF LH threads in these small size machines (Herbert, Eagle, Dronsfield along with Clarkson T&C cutter grinders) - Tracy are advertising 1/2" LH BSF for £15 - good value for money in my estimation.

Thread: Measuring tilt angles
13/08/2020 14:51:56

Swivel the table! and then check it with a gunlaying clinometer.

Thread: Aciera F3
13/08/2020 14:48:44

Barry Lee 3,

This morning I checked the X axis lock-bolt on my F3 and the bolt measures M8 x 1.25p with 30mm long bolt portion with a 12mm thread engagement (after it passes through the clamp washer and platten casting shield) the upper portion is 25mm high which includes the 12mm hexagon at the very top.

Wonder why the previous owner did not use the scale / slip gauge abutment bracket fixing? It seems the logical place to jump off from seeing as that is what it was designed to do!

Thread: Clarkson T&C grinder motor stopped
12/08/2020 14:27:29

Just a quick update on this problem:-

Motor replaced with a Siemens 3phz delta connected unit - everything works as expected. The original motor, an ASEA which was the original fitment I believe, had a minor thermal event deep in its bowels (bit like a curry but more destructive!).

Thank you to all the respondents to my initial query. It is always good to talk a problem over with like minded folks and this is the enduring strength of this forum. Thanks again!

One last point was the flat drive belt had seen far better days and I was surprised to find some machinery dealers asking for £50+ pounds for a Clarkson replacement! So I went to a local Bearing Supplier who advertised 'transmission products' and he got me one next day for £12 + Vodka and Tonic. It is a Pirelli Hevaflex, so looks to be a quality item.

Thread: Aciera F3
11/08/2020 16:29:08

Ian,

The drawbar thread for the W20 collet is a 19.6mm (although I have also seen 19.7mm mentioned) diameter by 1.66mm pitch. I found that this was impossible to gear for on a metric lathe so resorted to cutting the threads on an imperial change wheel lathe by, as mentioned by DC31K; the easy way is to convert it to an imperial pitch = 15.246tpi

This was as near to 16tpi so, on looking up the change wheels need for 16 tpi, I substituted a 51T wheel in place of a 48T which gave the ~5% difference needed to get to 15.25tpi. The thread is also a buttress 45/5 degree.

Enjoy your machine - they are a delight and if you have been really lucky with getting the accessories, like the high speed head, complex quartering table, vertical slotting attachment, the delightful dividing head and the really rare offsetable rotary table, then there is not much you cannot produce on it.

Thread: EN8
07/08/2020 11:40:42

Stay clear of stainless steel, too 'notch sensitive' for a critical part such as a wheel spindle. I remember well a scrutineer at a classic bike meeting checking wheel spindles with a magnet to see if they were stainless and rejecting any that were. I had a problem with my bike as it had Ti614 spindles and had to argue that they were not stainless but titanium, along with the spokes and spoke nipples and most of the bolts and nuts holding it all together!.

Fortunately he let the bike pass scrutineering on this evidence when I showed him a Titanium bolt from my spares box.

06/08/2020 23:03:56

+1 for either EN16T or EN 19T alternatively Ti614 also makes a good lightweight spindle!

...And no sharp corners at transitions of diameters! Nice radii.

Thread: Clarkson T&C grinder motor stopped
06/08/2020 22:43:48

Thanks Guys - I'll follow all those suggestions and report back.

Just to reconfirm - I have tried the lathe off the VFD (I use one VFD to power about three machines, all with similar rated motors) the VFD 3 phase output is terminated into a 3 phase 5 pin socket - I disconnect the plug with the remote control for the VFD power to off, swop over plugs and then use the remote low voltage controller to start / stop and speed control accordingly. There is also a jog function for my drill. Both the lathe and drill work as expected off the VFD so I am happy to believe the VFD is not at fault.

In reply to John Haine's second post - yes the initial value shown on the Fluke is 0, or at least a very low number (such as 0.7 ohm) and then ramps up to around 12 Ohms within 2 secs. I've tried the lathe motor resistances by the same method and get even numbers across all pins representing U,V, and W (motor connections) but a slightly different Ohm reading, 15.3 to 15.6 Ohms in the case of the lathe (slightly different power motor but still within the VFD rating). Just a note to add that the 'fat' plug pin is the motor earth, and pin 1 is the shielded cable earth connection connected at the VFD end but not at the motor end, this to ensure no earth loop to fool the RGB in the consumer unit!

The motor off my mates Clarkson is exactly the same type but his runs 440V star (Y) connections and runs OK - I'll change it over to Delta (|> before trying it on my machine.

Spindle and motor of the Clarkson both turn OK with no notchiness or excessive resistance, as you would expect. When the motor stopped - and after powering down! I checked the motor for any sign of overheating, it was cool to touch as was the spindle head on the grinder.

The Fluke meter response to the Ohm reading (the 'ramping' response) has been described to me by an electronics buff as a normal Fluke meter characteristic when checking a motor due to residual flux.

Thanks all for your responses!

06/08/2020 18:47:42

John,

It's a 220/240 Volt Delta wired motor so pin 1 being disconnected is normal in that configuration. The ramp up was from 0 > 12 Ohm not from Infinity down and was pretty quick in that the fluke was flashing 0.8 / 2.6 /4.9 / 7/8 / 10.4 /then stabilised at around 11.5 to 12 Ohm's (indicative readings in the ramp up) the ramp time was probably less than 2 seconds.

I,ve located another Clarkson nearby which the owner has offered to lend me his motor so I can swop them over to see if it has passed onto the EM home in the sky!

Thanks for your valuable input, always good to get a second opinion on things which seem to be baffling!

06/08/2020 18:03:11

Hi Guys,

Hope all are keeping safe and well.

I was using my Clarkson T&C grinder yesterday to sharpen a 6 tooth shell mill when, just as I had finished the last pass, the motor slowly 'died'. It was as if the speed controller on the VFD had been turned down gradually. I was at first concerned that the VFD had 'blown' - but as I interchange the VFD with one of my lathes by using a 3 Phase 5 pin socket I reconnected the lathe - turned on the power and the lathe ran as normal. This made me suspect the Clarkson motor had died - as an initial check today I Fluked the pin outs of the Clarkson connector and got the following Ohm readings - they were not stable readings though, as they tended to ramp up from zero to between the values of 11.5 Ohm to 12 Ohm. This I put down to flux effect within the motor.

The readings between the major 'earth' pin (at 12 o clock) and the remaining 4 pins was Infinity and Infinity between pin 1 (clockwise from the earth pin) and all other pins, then the 'ramping/ up to 11 / 12 Ohms between the pins 2, 3, & 4.

What have I got? a deceased motor? BTW reconnecting the VFD and trying to run the Clarkson motor did not result in any motion, humming, escaping smoke or otherwise.

Photo of 3 phase 5 pin socket:-

img_3190.jpg

 

Edited By Oily Rag on 06/08/2020 18:04:58

Thread: Quality small metric spanners
31/07/2020 12:42:13

Barrie,

As I mentioned in a previous posting, I had the dubious pleasure of working in a certain country for 9 years as a 'Localisation Engineer'. My job was to keep the locals on the righteous path to quality as they took over our design of a vehicle and produced it for their market. Some of the instances of their approach to quality can be gauged by what we came across. Pistons that broke in testing after 5,000km because they were full of slag and debris and the copper 'seeding' of the casting metal had not fully dissolved due to the main furnace not running at optimum temperature. The debris consisted of bits of tungsten carbide and something akin to EN16 swarf (chipped inserts and previous debris no doubt out of lathe swarf).

Then we had the first batch of pre-production engines which, during the acceptance test bed running, burnt all the exhaust valves out. This was a puzzle as the engines had in pre-production phase performed acceptably. I contacted the valve supplier to ask if they had changed anything - only to be told that they had not got the contract for the production engines because another company had under bid them on the production quote. Then they let the cat out of the bag with the statement that the quote that had won the contract had been lower than they could buy the metal stock for! Sure enough the valves were poor quality material well below the 21/4N specification (21% Chrome/ 4% Nickel) at 10/2N! The Buying department were complicit in this fraud and blandly exclaimed that the parts in question 'were to drawing' - they were completely oblivious to the fact that the material specification was part of the drawing.

The other problem we found was that whenever we introduced a process which could be construed as our 'IP' it did not take long for the suppliers to embrace our 'IP' and to apply it to other customers products.

Finally,we also had problems with our test procedures which the host company took and amended to their needs - this in many cases, in fact in all cases, substantially destroyed the objectives of the test procedures. An example of this was that the vehicles were required to perform tests in a sequence - such as a cycle that covered test track running at V.Max for 5km followed by decelerating down to walking pace in first gear for 1 km, then stopping and reversing for 50 metres, stopping and accelerating through the gears to 100kph, stopping and then repeating the V.Max to end of cycle. This was to be repeated for 1000 cycles. We found that the host company had lumped all the reversing cycles into one continuous cycle, all the 100kph into one continuous cycle and all the V.Max into one cycle! They just did not understand the need for the intermediate parts like the accels and stops.

This is one of the reasons why I fight shy of anything made in that country!

30/07/2020 19:44:56

Just found a photo of the Bergen tools mention above:-

img_3102.jpg

30/07/2020 19:39:43

I'm surprised that no one has mentioned Bergen tools - I have found these to be excellent design and price. I believe they are, or at one time were owned by 'US Pro Tools'. They also sell the very rare 'ratchet-less ratchet' (as did Britool, but I haven't seen one of theirs in ages). Ratchet-less ratchets utilise a sprag clutch system and when using on small thread sizes they have the advantage of not dragging the bolt/nut back and forth on the return stroke - a very annoying habit with even fine tooth ratchets. I have these in 1/4" and 3/8"th drives along with others more common ratchet tools from Snap On and Britool. For small nuts and bolts they are the 'go to' tools for me. The Bergen also has a very short handle 2 1/2" on the 1/4" drive and 3 3/8" on the 3/8th" drive. They are good for getting into tight spots and do not allow abusive over tightening being short handled!

The other 'nice' (sorry SOD!) ratchet I have is a offsetting handle on a Snap On (although I am sure it's a Blue Point - Snap On's lower market brand). I have as far as combination spanners a set of Halfords Pro's, and an assorted bunch of Britool (issued at Lucas in the 80's), Sears Craftsman (very highly recommended), and the odd Stahlwille, Facom, and Elora. Even have an odd 'India' brand spanners that get modified as required (rough as the proverbial dogs rear end but good quality steel but with a rough forging finish)

BTW - SOD tell your daughter the world's best sunglasses are Serengetti without a doubt - used by Arizona Highway Patrol and far better than Ray Bans (they're for the downmarket Californian Highway Patrol!) The 'Blue Blockers' are the eyeshades to have when driving over a dessert terrain.

Thread: Static balance gadget
28/07/2020 17:44:46

Use a Jones and Shipman grinding wheel 'knife edge' rotating balance assembly. But if you want to build one research how they did theirs. Discs need to be about 6" to 8" diameter with an incidence angle between bearing centres and prop centreline of roughly 60 degrees.

Has to be mounted true and level (so put some levelling adjusters on the frame), spin the prop assembly up and wait for it to come to rest, not if it 'rolls back', marke the lowest point and repeat several times. If all is well and it consistently stops in the same place then add some weight on the opposite side (Blu Tac is useful for this). Repeat and check again, more weight if it still stops at the same point, less if it stops with the weights 'down'.

It's a long tedious process but you'll soon get the hang of it - if not, sit down and have a cup of tea, and have another go!

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