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: Myford Super 7 Headstock Bearing Removal|
I had a test piece checked on a Talyrond machine a couple of months ago. The result was better than 0.003mm , so I was very happy with the results. I was going to replace the main spindle bearing, but decided to scrap and blue it to the spindle some 25 years ago or so. I am still very happy with the machine.
|Thread: Silver steel|
Stubs Silver steel is more commonly called W1 as it was a water quench hardening steel.
There is also O1 steel which is an Oil quench hardening steel. Some companies sell centreless ground round stock that is actually O1 steel and name it Silver Steel. The Stubs Silver Steel that I have seen comes in 36 inch lengths.
|Thread: Holding piston|
Edit, It should read 0.5mm per 40mm, not 0.05mm. Not sure how to edit the post to correct the wrong data.Neil
Old School, This is the RSA-444 piston material, 30% silicon. With these hypereutectic alloys with high silicon, carbide will not take fine cuts on this material. I finish the end face/ piston crown and rough the outside to about 0.1mm diameter. I then change to the PCD, insert is NP CCMH060204 MD220 , it is a 0.4mm radius and is positive cutting. I chose this small size because of the positive cutting geometry which I could not see in the larger 9mm insert . image here ,http://www.mitsubishicarbide.net/mmc/ja/turning_inserts/no_srs/20043582 I used RiceBran oil in a spray can, usualy us canola oil but ran out, so grab what was in the kitchen. Now have to buy another, she won't use it because I had it in the shed.My win. Anyway, I learnt something new in trimming these pistons. Normally, I have to clean the piston and liner with contact cleaner to get the oil off to work out the dry fit height of the piston. But with the rice bran oil, if I just blew the piston off with compressed air, made sure it was clean and tried the fit. I could get the same fit if I cleaned it all with brake clean or if I just blew off the micro turnings.The diamond insert is expensive, but well worth it. I run my myford at about 500-600 rpm, top speed in the low main pulley. The cut is put on by winding backwards the compound slide. On my one, each division is 0.04mm of pitch, so the slide is set at 0.05mm in 40 mm of travel of the compound slide. I turn the main diameter to about 0.02mm of size, then do not touch the cross slide until it is finished.The cross slide centre gib screw is tightened slightly to not make the axis so free on the hand wheel. I keep oiling the saddle slide quite often as well. after the cut, I wind the compound handle exactly 1 turn forward to bring the tool away from the work piece. I hand feed the saddle at a rate of about 30 seconds to cover the 14 mm or so distance. Measure or try piston and then take another pass. The tool is set as close as I can get it to centreline. Neil
Here is a piston I am trimming for a friends model diesel engine, 2.5cc
I set the compound over to about 0.75 deg, it is actually at an angle so that
|Thread: Sharpening Lathe Tools|
CBN are Cubic Boron Nitride wheels. It is either a matrix of the material on a metal wheel, so looks like a desic diamond coated wheel. The other type is a wheel with a compound like a diamond wheel, but the compound is CBN so looks like tire of bonded material,
HSS will load and dull a good diamond wheel. So when you use it on carbide it will be dull cutting compared to not using hss on the wheel .CBN wheels are much better suited to sharpening hss, but carbide will ruin and dull off a CBN wheel. CBN wheels last a very long time in a commercial environment, so will probably last a lifetime in the home workshop.
|Thread: Prevention of seizure in aluminium threads|
Castor oil and AFT(Automatic transmission fluid) will help. AFT is good if parts have just started to seize,but have not gauled. You have to be careful with castor oil, as it can allow parts that would not ordinary fit together, go together. Aluminium diesel heads, with an Aluminium contra piston, are assembled with castor oil , to prevent the 2 alloys from gauling.
Having extra clearance in the threads helps as well. On fittings that are subject to heat and vibration , I make the threads loose enough, that allow a layer of PTFE thread tape. It has worked very well for the stingers on tuned pipes so that if required, we can change them.
|Thread: Workshop lighting|
I have had the LED strip lighting in my shed for 3 years now. I would not have anything else. I am slowly converting the rest of the work areas with LED strips as well. The better ones are with the Ali extrusion and have a scatter / frosted plastic diffuser, the 1st ones were just mounted underneath the tool shelf without any covers. I have had no issues with either yet. I like the instant Turn on, and the now lower power bill as well. Not driving KW's of lighting in the shed anymore. The incandescent were changed with LED, but I really do like the better light spread from the underneath side of a shelf. I see now there are a larger choice in the light spread of the LED's now , angle of spread, and a huge variety of colour temps as well as varing lumin output per meter length.
|Thread: Sharpening brazed carbide tip tools for the lathe.|
If you have access to a microscope, you will see that the green wheels microchip the carbide edge being ground. There is a myth that carbide can't be damaged from heat when grinding. My experience is that carbide that has been hot when ground does not hold it's edge as well as the same tool ground that did not get hot. Dull green wheels and dull diamond wheels will both burn carbide. Lapping the tool back beyond the microchipped area with a lap is another option. I prefer to use diamond wheels as they generally do not microchip the cutting edge. There are very many different grades of carbide these days, it is hard to keep up. They do not all grind the same either. When brazing carbide, make sure that the tool is allowed to cool naturally, instead of quenching in oil/water etc.
|Thread: Safety glasses/guards|
It is the coloured ink, they treat the paper to make it print better. Use a paper that is printed with black only ink if you can find one these days. I found an old newspaper today from 1993 before they were doing the colour print. Looks like I will be keeping it for special occasions then. Any of the really cheap dish wash liquids work well for cleaning the plastic glasses. The secret is not to rub or smear the dust/dirt/grit into the plastic and then end up scratching them. I have prescription safety glasses, and they are not too bad after 3 years. My eyes will have changed before they get too damaged and need replacing. The secret is to keep them clean, so keep your head away from coolant mist oil splashes etc, all the things that make them go grubby. I always place mine down, upside down on the bench in a clean place, so the lenses can not be scratched or the glasses can't roll over across the lens face.
|Thread: Climb Milling|
You are right. Soluble oil coolants should not be sprayed through an air misters. The only oils that I have been involved with in the misters have all been edible cooking oils. I would think that sulphurised cutting oils would be bad news as well. Most machining centers these days have those oil recovery systems on them, to help to clean up the air from the coolant just being hosed onto the work piece. When they use the oil mister, the air quality is better than when they use flood coolant. Now days there is more research into cutter coating for cutting virtually dry, without the use of flood cooling. Some types of work, have to be flood cooled, but the technology will be developed to the point of just air mist or eventually just air will be the coolant and chip remover of the future. Soluble cutting oils I do not think are good to any environment, and I am not sure if it can even be easily distilled out of the water supply if it gets there. Very digressed from climb milling, but probably important anyway.
People out here are using an air mist , either through the spindle of the machine,or add on the side misters.
They sell special oils, but rice bran oil or sunflower oils works very well indeed. It is quite thin, alot thinner than canola oil.The amount of oil used is very small, basically you hold a piece of paper in the air stream, and after about 1 min there should be a small circular pattern showing that oil is coming out. If it is wet with oil then that is usually too much. Seems too good to be true but works very well. It is best to have 2 or 3 nozzels blowing down onto the cutter to cover for when it goes around a corner or is in a cavity. The air blast wants to be strong enough to blow the chips clear out of a cavity etc. I think the oil consumption is about 1 liter per month maybe less on the machine center.
The backlash in modern machine tools comes from the compression and tension of the materials it is made from. The higher the speed, the greater the forces and so effectively more backlash occurs. Modern ballscrew nuts are preloaded together, there is no longitudinal movement in the nut assembly. The only way it can get any backlash is for the screw to stretch apart and effectively change pitch. That is why the good gear has some form of dimensional feed back, either off glass scales or laser positioning. The latest in climb milling for cnc uses only about 10% of the cutters diameter as a cut per side, so a lot less forces compared to a heavier cut, but they do it at a very high feed rate and a very high cutter surface speed. Really neat to see.
On manual mills, a finish climb cut should not be that bad on most machines, the only real issue with backlash is if you are climb milling in a pocket, and then that could be a problem. Having one of those air mist blowing over the cutter will greatly improve cutter life and surface finish, either manual or cnc.
Edited By Neil Lickfold on 09/10/2015 19:49:46
With the new rodless pneumatic cylinders that are available today,they should be good enough to have on the axis to eliminate backlash , by preloading an axis with X amount of constant force. It is something that I intend to add to a machine when I get myself motivated to look into it further. Then there will not be any backlash apart from forces above the preloaded pressure. A friend has already done this to the X axis on his lathe. Works real well.
|Thread: Machining aluminium.|
Canola oil is a modified rape seed oil. It works very well for cutting Ali. A bit messy and gummy if you don't clean it up fairly quickly.Neil
|Thread: ER40 collet chuck|
0.01 to 0.02mm at the collet face is normal for regular tolerance collets, and about 0.03 to 0.04 at 50mm in front of the collet. I buy the RegoFix Precision series of collets. They are made so much better. The only people making a more accurate ER40 collet is the Big company from Japan.
What is often over looked in setting up an ER40 collet chuck is the run out of the outer thread for the nut. The thread must be concentric to the spindle, and then if the inside is not true, just recut the 8 deg per side inner taper untill it just cleans up. Regofix make up to 30mm collet for ER40 . I also like their high torque nut that has a special coating that allows the nut to be tightened without too much excessive force. I made my own ER40 spindle for a cue making lathe. With a ground test piece, my spindle is within 0.01mm tir. I also have made my own collets out of delrin to not mark the wood parts.
|Thread: A question for those who have set up industrial machine tools.|
Hardinge made special machines from 1 about 1978 and onwards that had offsets of 0.00001 inches, yes 10 millionths of an inch. Hard to believe how long that technology has been around.They are sub micron machines.
|Thread: Disposal of dangerous chemicals/substances|
If there is a company that does Aluminium annodising or Ali powdercoating they may want to take it from you, HF acid is used in the pre treatment before the alodine or similar treatment is used. If they only buy in ready to use acids, then your best bet will be a chemical supply company that make such solutions.
Companies that do Aluminium Hard Chrome plating also use HF acid in a pretreatment process as well.
|Thread: Myford Lever Collet Chuck thread|
Andy, The Er32 collets are really only any good when the pieces are the full length of the collet or more than 3/4 collet length engagement . The Myford will hold very short pieces and be very stable. I know loads of people love the ER32 systems, but for short small work pieces, in my view are not a good choice. My Grip true chuck is more accurate than the ER32 was for my lathe.
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