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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: Slip Gauges
25/02/2016 08:42:19

Alot of people made simple screw jacks with a 0.5mm pitch or the imperial equivalent fine pitch. This was because many years ago gauge blocks were very expensive. The other alternative was to use adjustable parallels . Now gauge blocks are quite cheap and affordable. But to keep them in good order they used to have wear blocks to use in the outer of the stack to protect the very special surface finish. They can be easily damaged if no care is taken.

Neil

Thread: Marking out / drilling holes in precisley the correct place !
18/02/2016 05:56:29

Years ago, in toolmaking, we had a bunch of drill and reamer guides. These took drill bushes and reamer bushes and were made to a nominal outside diameter. There centre spacing was set with length rods and trig. These were clamped into place and used on the drill press or mill, these were quite large for the clamp to be secured. We also used buttons, also spaced with length rods and trig. But a smaller hole was drilled and tapped, a small screw to hold in place, then an indicator to indicate the position. Lock the machine in place, then removed the button, and used a milling cutter as a drill/boring bar to remove the thread. Then drill to the size, another milling cutter used as a boring bar, then the reamer. We used this method until we had mills with digi readouts and of course a lot better quality mill.

At home here I made some small buttons with a hole in them. I then made a tool to go into the drill chuck that sits over the button. I then clamp after the tool locates the part for me. Remove the button and drill ream etc

Neil

Thread: Boring bars
17/02/2016 10:36:17

When the length to diameter ration starts to get greater than 5 to 1, like a 10 mm bar , boring 50 to 60 mm deep, have a small radius on the tool helps immensely. My boring bar inserts are all 0.2mm radius for that reason. They also need to be sharp. Sometimes having the boring bar above centre slightly can help with getting a better surface finish. If it digs in a little, the bar deflects to the centre line and reduces the cut depth. But when an on centre bar deflects , it digs in more as at goes further below the centre line, leaving a series lines or score marks.

If you can afford them, solid carbide boring bars do make boring longer holes a lot easier. For very deep bores, as been mentioned, line boring is the way to go.

Neil

Thread: surface rust on lathe ways
14/02/2016 06:54:33

The picture is not really good enough to make a call on that. I find that if the fine grey scotch brite or at most the redy brown scotch brite does not clean it up, and it is all pitted, who knows how much damage there is. I did a fixup on a Tesa comparator that has surface rust on it. The owner thought it needed to be reground and lapped again. From the tests I did, the main table was still very good. So we got lucky. But on a toolmakers vice that went rusty in my shed from a roof leak, it pitted so bad, that it took 1mm to clean up both sides, .5mm on each side that was rusted. That really ticked me off that was for sure.

Neil

Thread: Modifying outer bearing races
13/02/2016 20:54:43
Posted by Ian S C on 13/02/2016 10:39:14:

Great work Neil, may I ask, is the crankshaft heat treated, ie is the bearing area hardened?

Ian S C

I did not make the crank, only polished the bearing area that had some wear on it. The crank is very hard where the bearing area is. On previous damaged shafts, they are 60 Rc.

12/02/2016 22:39:05

Hi Gerry, the failure is in the crank shaft, it will deform and wear, once it gets a little bit worn, they deteriorate very rapidly. If you are careful and replace the outer race and steel balls when they just start to get some noise in them, polish the crank, you get more life from them. They last longer just by replacing the steel balls with the G3 ceramic balls. With my older engine, it has worked quite well, so tried this on the newer engine that uses 1/8 balls instead of the smaller 2.5mm balls. In all cases, they use a C3 clearance bearing, but more specifically use a clearance of Ø 0.02mm to Ø0.03mm. I like the higher end of Ø 0.03mm clearance between the inner and outer race ball clearance. The end float and loading position is still the same. In reality, model engines set the bearings so that they are in effect being used as Radial contact bearings instead of the regular deep groove position of running in the middle of the race. These engines do about 39300 to 40200 rpm. If the engine is only making power to fly the model at 275 to 280 Km/h they last a lot longer than when they are making power to be doing 290 km/h or faster.

Neil

12/02/2016 22:39:04

Hi Gerry, the failure is in the crank shaft, it will deform and wear, once it gets a little bit worn, they deteriorate very rapidly. If you are careful and replace the outer race and steel balls when they just start to get some noise in them, polish the crank, you get more life from them. They last longer just by replacing the steel balls with the G3 ceramic balls. With my older engine, it has worked quite well, so tried this on the newer engine that uses 1/8 balls instead of the smaller 2.5mm balls. In all cases, they use a C3 clearance bearing, but more specifically use a clearance of Ø 0.02mm to Ø0.03mm. I like the higher end of Ø 0.03mm clearance between the inner and outer race ball clearance. The end float and loading position is still the same. In reality, model engines set the bearings so that they are in effect being used as Radial contact bearings instead of the regular deep groove position of running in the middle of the race. These engines do about 39300 to 40200 rpm. If the engine is only making power to fly the model at 275 to 280 Km/h they last a lot longer than when they are making power to be doing 290 km/h or faster.

Neil

12/02/2016 10:51:33

Thanks Emgee, yes Profi, I am not a good speller, I will edit it. The main reason was to get longer life from the shaft bearing. The added rpm was an unexpected bonus.

Thread: Dial Indicators
12/02/2016 09:17:13

It is interesting about brands and type of equipment. If it gets the work piece close enough for what you are doing than it is fine. It only becomes a problem when you are trying to indicate something and the indicator can not reliably put the part to that level of precision. You then either buy a new instrument with a finer reading amount, or make a design your parts in such a way that you are not reliant on the indicator for the precision. I did buy many years ago a Chinese finger type indicator with a 0.01mm reading. It would show after about 3 months that the work piece was indicatored to better than 0.01mm, but was actually out by 0.02mm. It went into the bin. The Tesa indicator I brought to replace it, is still very good and I check them about 3 times a year for repeatability and incremental reading error. An example of needing better reading indicators is when I modified the bearing races. It was a lot easier to indicate the inner race of the bearing to be reworked with a 0.002 mm indicator as to using the regular 0.01 indicator. Trying to gauge a 1/3 of a reading on the indicator is really for the very young eyes. With the 0.002 indicator, that becomes 1.5 divisions, much easier to see for sure.

Neil L

Thread: Modifying outer bearing races
12/02/2016 08:59:26

The tools to assemble the bearings with and the to get the front inner assembly together etc.

assembly-tools.jpg

You can see the rear bearing puller and the assembled front inner race in the clear assembly housing. The hollow aluminium bar in the centre at the bottom, pushed the inner race and it's compliment of balls into the front outer race.

assembly-tools-required.jpg

12/02/2016 08:55:17

This is the crank and modified outer race assembled with ceramic balls in place, awaiting the heated case to be placed over the assembly. It is the easiest way to get the rear outer bearing shell into the case.

ready-to-assemble.jpg

And when the case has been assembled.

crank-in-case.jpg

Care has to be taken as if the shaft moves back in the case a few mm, the balls will fall out.

12/02/2016 08:51:23

Crankshaft polished with balsawood mounted onto 1/8 shaft and 3000 grit diamond paste. These cranks have the inner race as part of the crank shaft, also know as an integral bearing crank.

polished-crank-2.jpg

12/02/2016 08:49:14

I have set out to modify the the outer bearing races of 10X22 bearings for us in a 2011 Proi 2.5 cc speed engine. I want to change the existing that uses a 10X22 outer race with the polyamid cage and 9 balls to a cageless near full compliment ceramic ball rear bearing and a cageless front bearing. Both the rear and the front bearings become magneto bearings. The rear bearing taking the axial thrust and the radial forces of the crank assembly and the front bearing taking the radial forces and controls the amount of total endfloat between the two.

I made a fixture of sorts, that holds the outer ring while it gets turned. I made the inner bore of the shell holder slightly less than 0.01mm smaller than the outer diameter of the bearing shell. I used castor oil as a lubricant to assemble the ring into the fixture and had a clamp ring to aid in the assembly. Then I bored out to the diameter of the ball race to the centreline from one side and then diamond polished it. There is a ring inside that allows the extraction of the outer race. Some assemble tooling was required and some more tooling required to measure the position of the crankshaft to the front bearing seat. Other tooling to measure the position of the inner race to the outer race position as well. Instead of making shims for the outer race of the front bearing, I turned the end of the race shorter by the measured amount.

I have some pictures of the tooling and the shaft and case. The project worked better than I thought, and had a RPM gain of 300 to 400 rpm. I did not think that the cages could be producing enough drag to make that much difference. The idea of the project was to get a longer life from the integral bearing crank shaft, and a longer life from the front bearings. Im not sure on the front bearing life just yet as it has only done test bench running. The other engine with the home made outer bearing shell of the same design but using 2.5mm ceramic balls is lasting very well so far. This one uses 1/8 ceramic balls, so I expect this set up to last a longer time.

Fixture and Modified 6X15 outer shell. Turned using Kyocera insert ccgt060202mp-ck pr1425 on a 10mm shank boring bar at 500 rpm 0.1mm cuts 0.2mm diameter at a time.

outer-race-mod.jpg

Thread: 3D printing seems to have gone quiet. Where are we all at?
05/02/2016 05:06:38

Check this out from DMG Mori. https://www.youtube.com/watch?v=g8sT8ESfjrg

The new way of the future for manufacturing high tech things.

Neil

Thread: Cutting with a large tap
05/02/2016 04:51:14

Taper pipe taps and dies are a lot easier to drive compared to a regular tap. Also most pipe is free cutting mild steel.

Neil

Thread: Checking runout
04/02/2016 18:22:58
Posted by ega on 04/02/2016 17:07:24:

Am I right that no one has mentioned the point made by GHT about Griptru adjustment? He devoted nearly two pages to the subject in his MEs Workshop Manual, the central (!) point being that he counselled easing off and re-tightening the body screws before and after adjustment.

I had a look at my chuck, it has belleville type washers under the cap screws holding the chuck together.

What you say does make sense about the body screws. I have never has any issues with my chuck though.

Glad to hear the OP has found the cure to getting it running well again.

Thread: Cutting with a large tap
04/02/2016 18:13:16

That sized tap will be hard work in anything other than free machining. As been suggested, screw cut to size, but with a full form threading insert makes internal thread cutting that size quite a simple operation. It will take quite a bit to even run the tap through to clean up the thread to size. Buying a 1.5mm internal threading insert and holder will be worth while if you are making quite a few accessories. The advantage of screwcutting is that the thread will then be true to the faced reference and location diameter.

Neil

Thread: Checking runout
04/02/2016 09:11:43

My main Griptrue chick is about 30 years old possibly more, the new one is about 20 years old. I have hardly used the new one. I have the outside jaws on the new one and standard jaws on the old one. I just change chucks instead of switching out the jaws. One thing that I thought of when I 1st got the lathe as it came with this chuck, was to adjust the chuck with the least amount of pressure to hold the part true. I think they can be damaged by over tightening the adjuster taper screws. When ever I need to hold something very tight, I use the 4 jaw chuck for that. I rarely need the 4 jaw.Over the range the old chuck is upto 0.05mm tir out. But if zeroed in on a size it is still better than 0.01mm every time. I have not taken it apart for a service yet, but will do after reading the info and articles. Here is a picture of modifying a 6x15 bearing outer race to become a magneto bearing. The bearing is a very light press fit into the fixture with castor oil to allow the over size part to assemble. There is an extractor screw to take out the bearing shell. It was set up in the Griptrue because if the inner race did not run true to the outer race, I could adjust it to be true, then I could turn away the part of the bearing to the race center line. It happened with this bearing that no adjust was required.

outer-race-mod.jpg

Thread: Mitutoyo Indicator Help?
31/01/2016 10:35:12

I use baby oil to lube the insides of my DTI's . Seems to work a treat.

Neil

Thread: Boring Bars.
26/01/2016 08:01:34

I like using the dimple bars by Mitsubishi/ Kyocera or the vibration dampened bars from Sumitomo. I have done my own conversions on some tools by drilling a hole into the tool and then filling the hole with a lose tungsten carbide weight. They work very well at reducing the vibration from the tool and give a much better surface finish. Sandvik also do their range of tunable boring bars that are oil filled and have a piston that is screwed in and increases the pressure inside the bar.

Neil

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