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Member postings for Ian P

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

Thread: Stuck Chuck
07/01/2020 18:57:24

I have another thought on this stuck adapter.

Looking at the picture of the chuck that Jason posted, it appears that the hole in the face of the chuck is larger than the 3/4" thread, therefore I would assume that the adapter (if the threads were not binding) would pass right through.

If that is the case then there is no need to waste time unscrewing the adapter, what it really needs is 'tightening' from the back.

I'm not sure which way Steve has been turning the slotted end but if a 3/8" nut and a small diameter washer or two were put on the adapter it could then be rotated clockwise (looking at the back of the chuck) with virtually unlimited torque using a spanner on the nut and the chuck jaws held by any method.

Or have I missed the bleedin obvious?

Ian P

07/01/2020 18:42:49
Posted by Steve Crow on 07/01/2020 18:13:42:

Many thanks for all your suggestions and questions.

If that doesn't work Ill be fiilng some flats.

What wrong with using a well fitting screwdriver?

Ian P

07/01/2020 14:23:39

I did consider that the chuck thread might not run all the way through the chuck (it would be unusual though) but why the adapter would jam so tightly is a mystery. How tight it actually is something is depends on the person judging it and the method of applying the force. To anyone with a reasonable size vice on a strong bench, removing the adapter looks to be fairly easy, in Steve's case though he says he has a kitchen table workshop so just holding the vice and screwdriver in alignment whilst applying the turning force could be challenging.

Its not easy to see the state of the slot or the end of the screwdriver but neither look good. Not much can be done to improve the slot now that it is at the bottom of a recess, but the screwdriver looks quite rounded.

Unless the adapter to chuck thread has galled a good fitting screwdriver and some means of holding everything aligned should be all that is needed. I would think that the slot is potentially capable of imparting higher torque than anything gripping the short 3/8" thread.

Ian P

Thread: Anyone with a surface grinder near Leeds?
07/01/2020 12:02:28

We know small objects can be surfaced by moving them around in figure of eight pattern on wet and dry carborundum paper stuck to a flat surface.

Maybe you could use the same idea with your anvil by turning it upside down on a concrete road surface and then with a rope around its waist, tow it for few milesdevil

Ian P

Thread: Stuck Chuck
07/01/2020 11:38:18

Without wanting to take this thread off topic I am curious about the security of fastening a relatively large chuck to a rotary table by means of such a coarse small-ish diameter thread.

Quite rightly, on this and other forum there are frequent warnings about chucks becoming loose when a lathe is run in reverse. Surely the potential for a chuck held on a rotary table to come loose is (depending on the actual machining operation) is far greater.

The chuck in question looks to be ideal for attaching to a rotary table by clamps in the groove on perimeter of the chuck body, no worries then about it moving or stuck adapters.

Ian P

07/01/2020 11:25:08

I would still like to know why a headless screw can jam in the parallel (through?) thread of the chuck.

Ian P

07/01/2020 08:48:55

Thanks Michael, your link shows what that the adapter larger diameter thread fits the chuck body.

I now assume that the chuck thread has a shoulder or restriction (where the thread runs into the smaller tapping diameter) otherwise the adapter would pass right through the chuck body. If not what is it jammed against?

Ian P

06/01/2020 21:03:38

I am not familiar with Sherline lathes but it seems odd that its mandrel has a 3/8" UNC internal thread rather than the conventional male thread and register for the chuck/faceplate etc.

In any event does the screw with a slotted head actually have a shoulder at some point or does it just like a large grub screw that converts the UNC to the chuck thread?

I know the above does not solve the problem, but AIUI (or dont understand it) what it the screw stuck against?

Ian P

I missed the rotary table mention. Still not sure if there are two different threads on the adapter thing

Edited By Ian P on 06/01/2020 21:07:15

Thread: Correct use of slitting saw for deep cut.
30/12/2019 10:21:02

I think a clue to the problem was the 'pronounced dish' in the blade.

It sounds as if the arbor is not clamping the blade properly. I have seen slitting saw blades that were eccentric but never come across one that is not flat.

Ian P

Thread: Any real risks corrosion etc combining aluminium and steel
28/12/2019 15:42:30

Paul Kemp's reply says it all!

Until Chris TT addresses Paul's points I think its pointless offering advice and prolonging the agony as it were.

There are reason and places where two particular materials are best not combined so there is nothing wrong with Chris asking the question so we can offer advice in the right context.

Ian P

Thread: What Did You Do Today 2019
22/12/2019 22:00:15

I can see the connection, the spring is vaguely modeled on a colondevil

Ian P

Thread: Strange digital caliper behavior
21/12/2019 19:58:51

It is with deep embarrassment that I have to admit I have wasted everybody's time on my caliper problem!blush

To cut a longer story short, it WAS the battery.

The calipers are ones that are somewhat better than the usual Aldi and Lidl offerings and came from a respected advertiser on this site. They use a 3 Volt Lithium cell which I think I have replaced once since I bought them. What fooled me was that the calipers with the usual 1.55 Volt LR44 type button cell, give warning of the battery state by the fact that the display becomes feint. The display and all operations on this caliper were completely normal until this weird 'not setting to zero' fault occurred, I did have a spare battery but never thought to try that first.

This pair of calipers are on my desk and have never been in the workshop so I knew it was not a damp problem. This evening I was going to dismantle them and check the board carefully under magnification but after taking out three of the four screws, paused and remembered the advice I was given here so tried the battery.

Surprisingly the 3Volt coin cell measured 1.64 Volts so I am amazed that it functioned as well as it did.

Thanks everyone.

Ian P

20/12/2019 22:53:12

I think the site MG linked to is one where I learned some of the info about they work, I've just had quick look but not yet found anything relevant.

Dismantling and cleaning the calipers (which I have just done) has not changed them at all. I did see that that it has three solder-bridge jumper options (only No2 was linked) so now I'm curious and might experiment. (Maybe one of then disables the annoying auto-off feature)

Ian P

Thread: Heatshrink tubing
20/12/2019 22:46:21
Posted by norman royds 2 on 20/12/2019 22:18:19:

if you have smart phone try wish +lot off useful stuff regard norm

Purely out of curiosity, please could you re-phrase what you meant to say.

I assume it has something to do with heat shrink sleeving, but darned if I can see whatfrown

Ian P

Thread: Strange digital caliper behavior
20/12/2019 21:49:19

One of the digital calipers I have which has worked perfectly for about 3 or 4 years will not zero now.

At switch-on the display does show 0.00 but it the zero button is pressed without moving anything it sets the display to -0.02

Its totally consistent and always -0.02 Oddly when the zero button is held down it shows 0.00 but goes to -0.02 when released.

I have reasonable understanding of electronics and how these Chinese calipers work but I cannot work out what could cause this fault. I'm pretty sure its not mechanical as its the same when its locked solid.

Ian P

PS I've not identified the supplier but wondered if anyone else has seen the same problem

Thread: Meddings Pillar Drill, VFD and referb
10/12/2019 18:46:55
Posted by old mart on 10/12/2019 17:00:48:

The 1hp motor I have fitted to the mill gives 0.43hp at 25 hz and only 0.05hp (1/20 hp) at 5 hz. I have programmed the VFD to go no lower than 25 hz, lower is a waste of time, and all the four pulley ratios will be used.

Waste of time?

Obviously a big variation as to what people do with their machines and what type of work they are doing.

I find the very low speeds absolutely indispensable particularly for tapping. I regularly tap M2 and M2.5 without a tapping head, I tap up to M10-M12 also but if harder than aluminium finish off with a tap wrench or just the chuck key as a lever so adding (manual) power assistance.

Ian P

10/12/2019 18:36:26
Posted by petro1head on 10/12/2019 16:02:26:

My pulley has 5 options and its curently set in the middle

Ian is that the smallest pulley at the motor end?

Also, I notice you use up to 120Hz, did not know you could do that. I have mine set tp 50Htz max. Whats the advantage as I thought, obviously wrongly, that I had to match the AC frequency???

Edited By petro1head on 10/12/2019 16:07:17

Yes, smallest on motor so the highest reduction ratio and most torque.

Depending on the VFD sometimes they require to know the mains frequency as part of the set up procedure. The output frequency which governs the motor speed is a different kettle of fish.

I experimented to find the lowest and highest frequency that the motor was happy to run at. and entered those as the upper and lower values in the configuration. The motor I have ion the drill is one of the old square-ish Hoover motors and its perfectly happy over the whole range. The knob/pot I use is not calibrated or marked and I never actually know the chuck speed, I just go by feel.

Last week I put twelve 40mm holes in 16mm thick aluminium (in two stages) and it took just under one hour, I think I was running about 60Hz at which the motor should produce about optimum power. (after drilling all the holes the motor reached about 45 degrees)

Ian P

10/12/2019 15:21:37

I have a VFD on a 1/2" Fobco and have not moved the belt since I fitted it 10 years ago, Its on the lowest mechanical ratio (475prm on the rating plate) and I do all the speed changing using the pot from 5Hz to 120Hz so still have a very wide speed range

Ian

Thread: Keigan Motor
10/12/2019 13:49:27

I agree with most of your post SoD, I am pretty sure though its not a stepper motor, its more likely a motor very similar to those used in the larger brushless gimbals. In the video there is no sign of cogging when the presenter rotates the motor by hand.

I can see it finding a market in the educational field.

Ian P

10/12/2019 12:13:14

Its more a marketing thing than any new type of motor. From the description it is a well thought out combination of brushless servo motor, controller and a battery together with clever software all put together in a versatile enclosure.

I can think of lots of uses for it (camera and lens motion control) although once I found that it worked in a particular application I would probably end up re-engineering it and have the power supplies etc separated.

Ian P

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