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Member postings for Neil Lickfold

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

Thread: Screw Thread Measurement Utility
19/06/2014 10:25:19

If you buy a thread wire measuring kit with accurate wires, most quality sets come with a chart and a formula for working out the correct wire size for the pitch of the thread and thread angle.

If you have an engineers hand book or access to a standards book, there you will find the effective thread sizes that are used , so you can make the correct class of thread required.

But recently I purchased a thread mic that has different anvils, and the spindle does not rotate. The down side is the cost of the anvils. But worth it to me from a time saving point of view. You still need to know the effective thread diameter and have some form of reference for zero when the mic is larger than a zero to what ever.

I wonder how I managed to put up with wires all these years.

Neil

Thread: Chinese CNC Spindles ?
18/06/2014 20:13:04

I have one, the air cooled version, and the 8 deg inner taper for the ER collet needs to be corrected.

It has 2 problems, 1st the taper is not as close to the 8 deg as it could be, and it is not concentric to the bearings.I plan on setting it up and correcting this when I get time.

Neil

Thread: Carbonfibre Push Rods - Good Idea?
15/06/2014 12:49:51

It all depends on the modulas of the carbon being used and it's layup, and resin. Most prepreg resins have quite low melt/ soften points, so you will need to look for a resin that can handle temps higher than you think the part will be operating at. That being said, also the glue used to bond the end caps will also have to be capable of withstanding those temps as well. Carbon has quite a high compressive strength relative to it's tensile strength. Kevlar only has tensile strength. Quite often carbon shafts will have a thin skin layer of glass on the inside and outside to help keep the carbon together as a structure and to offer some hoop strength. Most of the carbon will be inline with the rod with a glass cloth providing the hoop and encapsulation.

Approx density of carbon , resin, glass is about 1.6 to 1.8 grams per cc , depending on mainly on the resin to fibre ratio. Ideally you would like resin to be the least amount as possible , that is about 28% to 34 % depending on the diameter of the filiments being used.

Neil

Thread: Sieg C3 Chuck run out
14/06/2014 22:14:43

clover plate , not my picture, from a google search.

3jaw-chuck-plate.jpg

Thread: internal screw cutting
10/06/2014 20:20:36
Posted by speelwerk on 10/06/2014 10:02:38:
Posted by Ady1 on 10/06/2014 01:37:15:

The ML7s greatest weakness was no leadscrew clutch IMO. Beats me why they never included one

If you have one with gearbox you can retro fit a leadscrew clutch, works fine. Nikoimg_5783.jpg

What does this do???

Thanks , Neil

Thread: "high quality steels"
09/06/2014 20:36:30

It just goes to show what can be achieved with what appears to be very a very primitive method. I was very impressed by the quality of material that they made , considering what was used.

No doubt , as time goes on, we will rediscover a lot of things.

Neil

Thread: Collets help
05/06/2014 07:14:44

How are precision collets made ?

Does any one know ?

Thanks Neil

Thread: Problem turning copper.
02/06/2014 12:35:26

You just can not have the tool too sharp to cut cooper. It does need a nose radius unless you want to feed it very fine. Some grades of HSS just do not hold as sharp an edge as others. Just like some grades of carbide do not hold a sharp edge. Using a fine hone stone makes a very big difference when turning soft materials.

Making a guide up so the stone is not rocked as the edge is being honed is also a big help in getting the tool sharp. When you look under a powerful loupe at the cutting edge you will see the various marks from grinding and the hone. Getting it as fine a finish and smooth makes all the difference. It should look shiny to the naked eye.

They now make carbide inserts with very high positive rakes for copper, and they are very shiny on the surface finish, and expensive.

Vege oil like canola or olive oil works very well with most materials including copper.

When everything is right, you do not need it to be going really fast to get a good surface finish.

Neil

Thread: First Time Milling Cutter Issues Help Needed Please
31/05/2014 03:00:04

If a piece of key steel hit against the corner of the plate leaves no marks, then the plate is harder than mild steel.

There are grades of steel plate that comes already pre hardened at about 40 Rc or so. That is very tough going with HSS tooling that is for sure. It should file very easy and be easy to put a ding into the surface. Capcrews are about 40 or so hardness, so it should file a whole lot easier than a capscrew does.

Neil

Thread: ArcEuro Model 100 QCTP on a Myford ML7?
30/05/2014 13:16:34

Sorry, Mine is the Dickson Type.

It used to be a 4 way tool block with a sprag type of arrangement that allowed it to index every 45 degrees.

I removed that little block screws and pin, and replaced it with the Dickson type setup. I did have the Axa type but it was too thick in the holders to get tools to the correct centre height. It just gathers dust for another project oneday.

I will take some pics of what I have done if that is of any help and try to post them tomorrow if all is well.

Neil

30/05/2014 09:14:46

For my one, I made a delrin bush that fits snug in the bottom of the tool block, and has drag on the bottom of the original pin. I made a stepped washer for the top.

The best part is, that due to the snugness of the delrin bush, when I rotate the tool post or need to clock it in, it rotates and pivots without the issues of the standard clearance tool posts.

Thread: soluble cutting fluid
30/05/2014 08:00:56

Knowing what I know now, I do not use soluble oil on my lathes at home. I prefer to use either small amounts of vege oil,(canola or what ever is the cheapest at the super market, where needed), or the light cutting oils.

I worked with some production machines that had oil only and others that had the soluble coolant. The machines that ran only cutting oil, had the least wear on the bed ways and were in the best condition. The machines that used soluble oil coolants had the most wear and were worse for it.

Neil

Thread: Tool Shapening
24/05/2014 01:23:18

Those diamond dressers on an small handle do a great job of wheel dressing.They are about 1-1/4 inches long about 5/16 or so wide. They are just great and last a long time.

I like using the White wheels for HSS, not sure what they are called to order them. The only issue with using the side of the wheel is being extra careful if there is no side rest support. As been said above, I would not use a star or rotating wheel dresser on the side of any grinding wheel.

Neil

Thread: Sieg C3 Chuck run out
22/05/2014 07:48:23

I am not sure exactly how your chuck assembles onto it's backplate. But on my myford std 3 jaw chuck, I put some bellvill washers under the capscrews. Then it allowed me to lossen the retaining screws a little, and adjust the workpiece to zero , then I tighten them up. Older chucks tend to have areas where they run well and areas where they are not so good. Since it was not right, I made it adjustable. On my chuck backplate I trimmed the spigot diameter down a bit to allow for the adjustment.I also trimmed an allen key down to get in behind easily.

Neil, If you can not make it right, make it adjustable.

Thread: Poor surface finish
17/05/2014 00:13:30

A part from motor vibration, also check the simple things like the pulley running true on the motor. On my lathe I had to bush and rebore the pulley. I have a piece of ruber between the motor and mount plate . I also have some rubber washer made also to help it become isolated. Now I can have the motor running and the dti does not move on the work piece.

I also changed the one piece belt to a segmented belt. When it comes around to replacing the current head stock belt, it will be replaced with the segmented belt as well.

My lathe had a problem with the adjustment of the 1/2 nut alignment on the lead screw. I put a dti on the screw and adjusted it , so the screw was not pushed in an up or down position. This did help over all .

Neil

Thread: Precision diameters
16/05/2014 22:44:23

Andrew,

The alloy has been specially formulated for the model engines at a very great expense by an individual who has always been looking for the best. He has been kind enough to share this technology to others so that more can enjoy the benefits of this material. It does not fall into any of the commercial number series of alloys, and it is very expensive.

From looking at a Kallenberger internal wheel spindle, it is not as controlled as the main head stock spindle. There is a very small amount of movement detectable with the the fine dti, the head stock has none detectable. As far as I am aware, there are no high speed super precision bearings. To get then to run fast,they have to have a little more clearance, Most precision bearing set ups have some form of spring loading on them to allow for heat expansion etc. Often running them at the highest rpm range, the work piece does not come out as round as it would if it were run at a slower speed. On my Myford setup, I can not run it in the high speed range as it will create heat in the head stock tapered bearing.

Howard,

You are very correct and bring up a lot of very valid points. Diesel injector making was one of the most difficult to produce parts in a production enviroment.I used to work for a company that made injector pump parts and repaired them.

Most normal inserts that you buy are not ground to a sharp edge. There are ground sharp edged inserts for cutting Aluminium. Like wise for the PCD cutters, There are a series that are sharpened with a positive rake geometry that will take micro cuts when sharp. PCD needs to be EDM ground and some are a lot better at it than others .To control the piston, the bottom of the skirt is made bigger than the seal band diameter, as they are a tapered liner, the skirt diameter fits at about the diameter of the transfer ports, giving the piston very little room to rock around. Traditionally the pistons were more of a barreled shape,or were parallel to the pin and then slightly tapered to the skirt, although these did work, the newer design with a large skirt performs better. Another aspect is the pistons have a small relief after the seal band area, about .1 inches long, to force the piston to behave like a ring. This also improves over all efficiency. Model engines get away with stuff that full size just can not, but at the same time create their own unique sets of issues. An interesting experiment was to take the set up that worked in a model diesel engine and try to run it as a glow engine. It did not per well at all. It did run however, but was too tight and showed signs of over heating. But the glow engine did not make good enough compression to get the engine to run as a diesel on the fuel supplied. A special brew with more ether was needed to get it to start. it was interesting to do and see what was the results.

Like I said, my setup is not good enough to make the pistons for the modern racing diesels, certainly good enough for a saturday afternoon park flier.

Thread: Milling cutter damage - what am I doing wrong
16/05/2014 09:15:33

If you are running a high speed steel cutter at 360 rpm , and it can not take a 1 or 2 mm cut, then your machine does not have enough rigidity.

In smaller machines you would be better off using a smaller 8 or 10mm end mill.

8mm and 10mm tungsten carbide cutters are very affordable now days.

You can run a carbide cutter at higher rpms, The most common cause of cutter damage is by swarf getting trapped between the cutter and work piece, Having a high flow of coolant or even an air fog buster onto the milling cutter will dramatically increase tool life.

Neil

Thread: Precision diameters
15/05/2014 20:37:00

The alloy used in high performance model pistons contains 30% silicon among other things and is very low expansion. Typically the liners or cylinders are made of 9-11 % silicon material. Usually what happens is when the engine over heats, the liner and the head expand, making the liner larger than the piston, and it just slows down, it is very rear to see a seizure. Essentially the top 2mm of stroke or so on the setup effective runs dry with no lubrication. These are the highest pressure areas. Small gains in the effective seal have a huge effect on power output and overall efficiency. In one example of tuning, the same timing numbers were used, but made into a square arrangement, so the bore was almost the same as the stroke, the power output gain with this engine with a small change in the piston geometry made a power gain of approx 7% . The new setup makes more power for a longer service time, a lot of the extended life is due to the profile of the piston and making it so that it rocks less in the cylinder. The high performance model diesel engines are the most critical in piston fits, and the best of those engines are now turned on sub micron CNC lathes and sub micron cylindrical grinders. What I can achieve for the glow plug engines, would not make a world class piston fit to the modern racing diesel engines. The glow plug engines are a little bit more forgiving. For general purpose model diesel engine with a regular liner in a case , my set up is fine, but the newer integral liners where the head is part of the barrel, is a very different matter.

Cylindrical grinders are usually far more accurate machine due to the precision of the work head bearing set up, and the very low vibration from the balanced motors. Very accurate head bearings do not spin very fast to maintain their accuracy.

Changing my lathe to the smoother 3phase motor on a VFD has made a very big improvement in surface finish.

One last thing, the tools have to be very sharp , when they are dull , they tend to burnish as they cut, those will not work as well either. If the tool can not take a 0.002mm cut with the oil, it is too dull. The high silicon alloy is so abrasive, that even carbide tooling does not last very long when trimming pistons. So I rough out using carbide and then use the diamond tooling for finishing, usually leaving only about 0.05mm on diameter for the diamond finishing insert.

Thread: Deckel SO Cutter Grinder
15/05/2014 07:54:11

I really like the D bit grinders, there is so much that can be done with single lip cutters.

If you get the double sided wheels in either diamond or cbn, the you can grind thread cutting tools and the like. Also do bull nose radius cutters( offset corner radius cutters)

I have been looking for one, but they are too expensive even second hand. The cheap import ones are not as good as a Deckel.

Neil

Thread: Precision diameters
14/05/2014 12:42:48

I do not know the Ra values sorry. But I think the reason it works better is that the interference fit, effectively burnishes the piston to the final running fit size. When lapping , you are taking away these peaks and so the piston can not burnish to get the liner specific fit. I think this is why when you run a piston in another liner, it does not run as good as a new piston that was fitted to that liner. I have not found a way to make the lapped ali pistons work.

Hope that helps.

Neil

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