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Member postings for Will Bells

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

Thread: Lathe Spindle Clutch
20/03/2014 22:39:38

Hi Coalburner

I made and fitted a cone clutch to my Denford 280 probably 10 years ago now, which is geared head, but has adjustable cone pulleys for variable speed control.

My lathe is converted to single phase which doesn't really like being switched on and off frequently, which is why I originally did it, but having fitted it, I wouldn't want to be without it and it's used very frequently.

I put the clutch in the original motor position connected to one of the cone pulleys and moved the motor position to drive the clutch by a belt.

My lathe was bought cheaply and in poor condition, so hacking the thing around to that extent didn't really worry me - but had I had a near new or expensive lathe, I would have thought long and hard before getting the angle grinder out !!

Cheers - Will

Thread: Some advice on Mild Steel types please
22/01/2014 18:23:28

Hi Paul

I would go for Bright Mild Steel and try hard to get the free machining stuff, as Jason has said. If you get any old steel, getting the right conditions to get a good surface finish with our lathes can be almost impossible (for me).

BMS can distort through internal stresses when machined, but this is normally more evident with flats, especially with a longish piece when only one side is machined. With bar I never think about or have a problem in the lathe, probably because the stress are evenly distributed.

Cheers Will

Thread: Making Protective Bellows
20/12/2013 22:56:29

Hi Doug

I made some latex parts along the same lines, but with thinner wall section, for an inventor a couple years back, so sorry I can't post a photo.

I made the mandrel from aluminium and because I made around 25 identical parts for him, I built a motorised rig to dip slowly and repeatably. Dipping cycle was around 3 minutes. The long time is just to get a thin even coat as it flows off the mandrel on the way out of the latex. If you only need one off, you don't need to be quite as careful.

I made another rig to dry each layer by rotating axially, keeping it horizontal not vertical so that the liquid was spread evenly as it dried. I forced the curing with an IR heater and from memory it was still an hour between dips to cure in all the ridges, which is when the latex goes clear.

The lathe with slow speed would work just as well for the drying.

It was normal liquid latex that I used and it takes quite a few layers to build up a good thickness if dipped slowly. I found that the mandrel needed a mirror finish and needed to be cleaned with isopropyl alcohol (Maplins) to prevent pin holes on the base coat.

Like you, I dusted with talc and rolled the parts off the former, making sure the surface coming off the former is also covered with talc immediately. It doesn't stick to the mandrel, just stays put because of friction - but it sure sticks to itself !!

The finished part is strong, but not like neoprene - more like silicone as it will tear easily from a cut or nick. But if its for an application that isn't treated badly, it could work.

Nice Christmas project and good luck.

Cheers - Will

Thread: kasenit
20/12/2013 21:55:31

Hi Roy

Just checked my nearly full tin smiley

1. Heat part to bright red and put into the powder. Move it around so that it sticks all over the part.

2. Re-heat to bright red (careful, you need tinted goggles as it seems to glow incandescently). Plunge straight into cold clean water.

For a deeper case, do step 1 twice before step 2

(Julian, I've never needed to use water as it has always stuck straight away for me)

Cheers - Will

Thread: Forming Screw Heads
28/11/2013 00:06:09
Some good progress
Made another tool as per John's suggestion with a screw ejector pin.
First attempts head shape not good but at least I could get it out of the die with the pin OK.
Then the penny dropped - I had been hitting the punch as if I was riveting it with multiple hits of a medium hammer, not like a flypress.
So I gave the next attempt one massive clout with a mash hammer and job done!
I need to change the punch shape slightly to what I want, but I'm a happy bunny.
Can't wait to get back in the workshop to finish them, although that won't be for a couple of weeks now.
Cheers - Will
27/11/2013 10:34:30

Yes, I probably should have given more detail in the first place - sorry.

The screws are 1 inch long, threaded 10BA (~1.6MM) over 6mm ish. Some will be threaded to the head.

Material is Nickel Silver

I need 24 in total and they are the spokes for two replica fishing reels (based on old Aerials), so they need to be straight and aesthetically excellent as they are visible.

I want to form the head first, then I'll thread.

Funny though, I've completed all the machining for the other components without real problems and these spokes, which I thought would be easy, are a nightmare. Couldn't even find the material in the straight condition, only coiled, so I ended up making a roller straightener to get this far.

Anyway, enough of my snivelling, I am in the workshop again tonight so I will make a jig as per John's first suggestion with an ejector rod against a grub screw at the bottom of the shaft hole. I'm thinking I may hit the head with one punch first, but if I need to I'll use two progressive shapes to keep it more concentric. This construction is nice and simple and should let me make it more accurately than my previous attempts.

My lathe (or it's operator) is not capable of machining this diameter between centres, unfortunately. I did wonder about splitting the die laterally as you suggest John, which could still be a possiblity, but I'm concerned about getting it accurate.

Will let you know how it pans out.

Cheers - Will

26/11/2013 18:13:58

Hi All

Really appreciate the suggestions, thanks.

John, the construction of the tool you described is very neat and solves one the key issues I had. I'm going to give that a go and post the results (or perhaps the screws in two parts if they go wrong again !!)

Cheers - Peter

25/11/2013 22:59:09

Hi All

Anybody out there made any screw heads in the workshop by forming, ie by cold heading or upset forging type of techniques.

I need to make some fairly long special 10BA screws and obviously the shaft is too small to turn and hence I need to make the head by hitting it.

I've tried to make some simple tooling and make the head in one hit, but I had a variety of issues ranging from malformed heads to the part sticking in the tool. Nearly there, but no coconut.

So has anybody managed to do this in the workshop and if so, what was the design / principle of the tooling ?

Cheers - Will

Thread: lathe
18/10/2013 18:08:13

Hi David

The play could be in the leadscrew if it's worn (or made that way), but it could also be in the thrust bearings, ie the bearing arrangement where the handwheel is.

These are usually adjustable, or sometimes a bearing that can be changed. Suggest you have a look under the cross slide and see where most of the play is.

If its the leadscrew, it's probably the nut that's worn, which could be made on the lathe (out of phosphor bronze), which would be a nice project to get to grips with internal screw cutting.

Will

Thread: Clinch systems
09/10/2013 21:59:54

Hi Windy

You're right, these sort of clinch fixings need no hole. They are widely used in automotive (and I think my car is held together with them) but I have never seen them for really thin materials, such as your 0.1mm.

They are great in shear, but peel strength is limited. Manufacturers like them because what you see is what you get, so unlike welding, if they look and measure right, they are good joints.

They have been around for donkey's years - I think Tox from the US was an early developer. I suggest you drop them a line pretending to be a manufacturer and ask them if they can join your thickness and material, which may put you on the right track

Cheers Will

Thread: A compact gearbox
22/09/2013 20:28:53

Hi Danny

I suspect that you will find that the pinion is a sintered part and hence the hole is made with the flat as part of the same pressing process as the teeth. Usually they are made from sintered bronze.

Peter

Thread: setting 8 degree taper for ER collet holder
15/09/2013 12:39:06

Hi Doug

Another possible method of measuring the top slide angle accurately is to take a cut off a piece of scrap bar in the chuck with the top slide at a position near its extended position and repeat the cut with the top slide near the other end.

You need to know the exact distance the top slide has moved (with the dial & leadscrew) and you need to measure the two diameters of the turned bar. The rest is down to a calculator.

I put some small marks on my top slide and tend to re-use the stepped bars until they disappear.

The method is theoretically spot-on, providing the lathe is accurate to start with wink

Peter

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