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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: 1960's Car Steering Wheel Taper Angle
26/03/2021 14:32:34
Posted by Oldiron on 26/03/2021 14:05:31:

Hi DR-

Measure both diameters with your vernier caliper. Subtract smaller dia from larger dia & this gives you the taper per inch.


How does that work?

Thread: Any advice on how to cut/file a 45 degree chamfer on a 1mm steel sheet to EXACTLY 45 degrees?
25/03/2021 12:31:46
Posted by John Smith 47 on 23/03/2021 13:41:47:

Thanks for all your quick responses
[Note I have now added a PS to my post of 12:36 today]

Regarding accuracy of the 45 chamfer, I need to make a bit load of them at least 32 of them and they ALL need to be able to meet and create a 90° join.

The reason for the accuracy is thatt they are for magnetic guides and even a 0.1mm gap will cause a significant drop in magnetic pull.

I'm not sure what 'magnetic guides' are but if you want the magnetic force to hold these parts together at right angles and you are concerned about a 0.1mm potential gap you might need to use guage plate or have the steel parts hardened.

Since these items have more or less a cutting edge (like a plane blade) they will be very subseptible to damage or burrs so even if it was a perfect 45 degree bevel it might not remain so for very long.

Since you mentioned this was an idea for a 'product' it might be sensible to have a batch made by an engineering company or an individual rather than buying machinery and learning how to use it. As others have said the most appropriate DIY method is that suggested earlier by Andy Stopford .

Are you hoping that the magnetic force will hold two parts together at a right angle just by the contact along the bevelled edge?

Ian P

24/03/2021 20:44:27
Posted by Jeff Dayman on 24/03/2021 20:18:59:

"PPS Luck your house has all the walls at Exactly 90deg"

As if that has ever happened! (I'd settle for 'somewhat planar' in our house) smiley

In the spirit of the OP's expectations of 'EXACTLY' I would say that most houses are walls at exactly 90 degrees.

In our home I could put a square table in the corner of a room and it might fit perfectly but I dont know for certain that the table is accurately made.

Personally I dont have a high opinion of British housebuilders but I accept fitness for purpose serves here.

Ian P

Thread: Making hexagon nuts on a rotary table & mill.
16/03/2021 15:11:15
Posted by IanT on 15/03/2021 18:04:03:

Depends on the size of 'hex' bar you need Phil.

I haven't been able to find very small hex-section brass bar, so if I want to make 14BA nuts (which are expensive) or 16BA nuts (which are unobtainable), then I have to make my own. It's a problem for me, as a scale G3 wagon can use a lot of these small parts. A 5/8th (pre-war) Whitworth nut is 0.7mm AF in Gauge 3 for instance.

One problem with thin materials is that they will simply move/flex if they are extended too far without support. One solution is obviously to only extend the material out a little but then this greatly extends the time required to make a usable length of hex bar.

My solution (whilst far from perfect) uses a hand shaper and works, although it's still not as fast as I'd like. As I need to get a uniform part thickness, I first machine the aluminium support to ensure it's perfectly level - which is much easier than trying to set a small part in a vice. The small Hex block is simple to turn after each cut and sometimes I just hold it in place - with a fore finger pressing on the part. No problem with a manual shaper but certainly not advisable with any form of rotary or powered cutter - although with a toolmakers clamp (as shown) a mill could be used.

My next experiment in this area will probably be to try a Hex draw-plate, using a small Allan key to make the hex-hole punch.





That looks a good way of making very small hex barstock. Machining the ali 'bed' first to get a reference plane makes good sense. If you start off with round rod and do three faces you then presumably have to raise bed for the next three?
Is the cut taking place on the forward or reverse cutter stroke? In normal shaper usage it looks like the small diameter work could easily buckle as its pushed towards the indexing hexagon block.

Ian P

Thread: Making a 3/4 x 16tpi lathe spindle thread protector?
12/03/2021 17:19:34

If its purely to cover the exposed threads when you are using the Morse socket then something as simple as a short length of PVC tube or even a turned wooden sleeve could just be a push fit.

Unless I've misunderstood the requirements.

Ian P

Thread: Plugging incorrect holes
12/03/2021 10:37:44

They will stay put. Your problem will be drilling and tapping the new holes into two different materials. The steel screw will not cut as easily as cast iron and the drill and tap will get pushed to one side.

Could you make a screw out of cast iron and loctite that in. Alternatively enlarge the existing holes to say M6 and then redrill.

Ian P

Thread: Twin Mill\Drill Overheating.
08/03/2021 12:47:57
Posted by James Frankland on 07/03/2021 21:04:36:

That ring at the top of the bearing, the thing that i said needs to come off did have a single, small grub screw in it.


Its possible that there is a brass pad under the grubscrew as the ring/collar may actually be a nut that sets the bearing preload. If it is a nut then the grubscrew hole may double as a recess for a peg/C spanner. I would look very closely (magnifying glass) where the shaft emerges from the nut/collar.

Ian P

Thread: DTI's Its all in the name
06/03/2021 16:58:19

I don't see any spelling errors

Ian P

Thread: Help needed, can't release cast iron wheel
06/03/2021 16:56:50
Posted by john halfpenny on 06/03/2021 16:29:54:

Not easy because heat will also tend to expand and lengthen the spokes, which will tend to tighten the hub on the shaft. Quick heat on the hub, a bigger puller with more arms, and a big hammer.

Edited By john halfpenny on 06/03/2021 16:31:13

Fully agree.

Even though your puller looks a bit on the lightweight side its worth tightening it to the point of not quite destroying it, and then one big whack with one big hammer!

I learned a lesson in the 60s when I ruined a brand new (Pickavant?/Churchill?) hydraulic extractor trying to get the flywheel off my Mini 1275s (held on the crankshaft with a taper). I just kept tightening and tightening until something broke in the hydraulics. Next day friend came round with his plain mechanical puller, tightened it up and with one tap from a lump hammer the flywheel popped off.

Ian P

Thread: DTI's Its all in the name
06/03/2021 16:39:03
Posted by Steviegtr on 06/03/2021 13:52:27:

I needed a finger type DTI. The Mercer one i have is a bit iffy at best. So i bought one off ebay. Just a plain faced cheap item to do what i need . Accuracy not that important.

It was £16 & in the picture it looked a pretty yellow colour. It arrived in a nice plastic fold open box, with 2 different size dovetail. All good & works fine. But in the ebay pictures it was a plain face. Look at the one i received. You have got to laugh.



I've looked inside a few DTI's and in all of them the actual mechanism seemed quite simple, I'm now wondering what the 7 jewels do, have you counted to see they are all there?

Ian P

Thread: water level sensor
04/03/2021 12:31:56
Posted by mechman48 on 04/03/2021 12:05:20:

That would be neat, but what would I make it from bearing in mind it will be 4mm diameter or less.

The simplest method works best, have a look at...

4mm Diameter Solid Delrin Polyoxymethylene (POM) / Celcon Plastic Balls Simply Bearings Ltd..

work on the acronym 'KISS' . Sometimes projects are over engineered where 'simples is as simples does' to closely paraphrase a line from a well known movie.


I was going to look up the density of Acetal but looked at the ball you linked to first. Not surprisingly one line of text below the detailed specification states 'These balls will not float'. TBH that is not strictly true as they would float on Mercury at least.

Ian P

03/03/2021 20:37:06

Unless I have the wrong end of the stick, Duncan is looking for a system that can measure the level of water in the boiler. I single sensor can be made to detect the presence of water at a particular level in the tube but I would think several sensors would be needed at different heights if this system is going to control a water valve or whatever.

Noel S mentioned 'servo' in his reply, that might need some type of analogue sensing rather than just one 'above' and one 'below' sensors. I can see quite a bit of development being needed before one could be confident that the water meniscus was actually between the two sensors and not below the bottom one (or above both). That bit might be trickier than the optics.

Ian P

Thread: Would this improve the quality of signal to a CNC machine?
26/02/2021 20:07:02

I've put this in the Tea Room as its mostly for discussing the pro's and conn's of cheap versus expensive cables between PC's and driven equipment.

Is seems that (apparently) transferring digital audio signals is best achieved by using only the highest quality cables. I have always understood that digital was digital and thought that as long as a USB cable transfers the 0's and 1's to the far end it would have no effect on the sound quality. Since the cables in the links below improve the sound quality, would these cable make CNC machined parts even more accurate?


Edited By Ian P on 26/02/2021 20:08:11

Thread: Damaged mill
21/02/2021 13:31:33

Aluminium would be fine. If you are making one from scratch you can optimise the design slightly at the same time.

Position the bolt so that it only just clears the diameter of the quill, (might need a longer bolt than you already have) that will give the most direct clamping force.

No need for the quill bore to be in the centre of the 'ring shaped' part, if making it on the lathe the part could look like an eccentric so that there is plenty material for the bolt head and clamping nut to seat on. If you dont already have an indexing handle then just have a clearance hole for a long bolt and have a flat to stop the bolt head revolving. Not sure what the holes and dowel pin are for but obviously you will need to them into account when deciding on the outer profile.

Ian P

Thread: Paper under vices.
20/02/2021 09:02:10

Putting anything compressible under the vice seems illogical to me as the act of tightening the holding down bolts will cause distortion in the vice body.

Ian P

Thread: 'Converting' a thread
19/02/2021 19:32:38

Since there is no real loading or stress on these thread why not 'overcut' the Russian thread with the 0.7 (32tpi?) you want?

I know this will offend many people here but is a practical and simple solution. Yes not all parst of all threads will be in engagement but there will be more than enough to ensure alignment of the optics

Ian P

19/02/2021 14:24:17
Posted by Bountyboy on 19/02/2021 13:52:26:

Love the comment,

”Claims to have case metalwork”

hope you managed to assemble it?

'CSE' in metalwork. More than I ever got!

Ian P

Thread: Setting up mill
16/02/2021 22:05:11
Posted by richard greeves on 16/02/2021 09:25:31:

brake discs has a runout so are not truely flat, this is push the brake pads back into the calliper slightly when you are not applying the brake,

Not strictly true, If there is any run-out it would do as you say but not how disk brake systems are supposed to work.

Pads are normally retracted by the piston sealing ring restoring itself from its deformed shape that it takes up when it grips the piston as it moves forward.

The amount of piston movement when brakes are applied is quite small so don't need to move back far to clear the disk surface. Untrue disks and less than perfect wheel bearings can 'knock-back' pads so that next time the brake is applied the extra clearance has to be taken up resulting in more pedal travel.

Ian P

04/02/2021 20:52:50

As Tony said the DTI probe needs to be close to horizontal if you are you get anything near accurate height measurements. The cosine error with the probe as close to vertical (as seen in your picture) must be significant!

A plunger type indicator is possibly a more suitable device if you want to measure absolute distances, lever types are good for comparative readings but since you are using a block under the probe that will allow the probe on your DTI to be set parallel to the table surface so the height readings should be quite accurate.

I usually indicate directly of the table surface, sicne we are only looking for height changes in tenths of a mm I have never found the 'T' slots gaps a problem as the probe ball tip will cope with half a mm easily.

Ian P

Thread: Using an old microwave transformer
27/01/2021 13:14:05


When dismantling an old oven to extract the transformer be aware that there may still be lethal charge in the capacitor even though its disconnected from the mains. In theory the oven manufacturer will have fitted a bleed resistor but its best to be safe.

I have no bad experiences or anecdotal knowledge but suggest that anyone contemplating repurposing the transformer does some research beforehand.

Ian P

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