Member postings for Neil Lickfold

It is often done to sacrifice one tool for smaller shorter work. At 36mm of a working length is starting to really be pushing the boundaries of diameter to length ratio, as the support material under the insert is where it is the thinnest. I have a Mitsubishi bar that I modified to get to 45mm deep and really it should have been a carbide bar, as the tool does chatter more than I like to see in a thread form. Sadly there was no tap readily available for the thread being made on the repair. So both parts were screw cut. Swarf or chip evacuation is the biggest problem when the bar to bore gets very close. So just have to watch the depths of cut or volume of material being removed. Some materials make fine chips and they can be lodged between the bar and the minor diameter. So coolant or a vacuum cleaner running with a nozzle very near by does hlep.

Super glue and 620 can be as thin as 0.01mm, and if the surfaces are flat enough, then down to 0.005mm

You can also use super glue to hold in place while assembling, or use Loctite adhesives like the 648 or 620, but 620 is very slow to properly set. Deburr your shim and try to keep it flat as possible. It will only need glue on the outer perimeter, and try to keep it away from  the screw holes. A small amount of Oring grease around a hole on the part and around the hole of the shim, is usually enough to stop the glue from wicking to the threads.

Edited By Neil Lickfold on 30/07/2022 14:26:56

I get around it by using the NFTG series of inserts, and regrind the insert to become an insert to cover up to 2.5mm pitch and put the radius required on the end, so not sharp tipped. They are available from Sandvik, and some others too. The inserts sit on a 3 point tapered seat. They come in 12mm and 16mm shank holders in steel and carbide. I use them for all the threads under 20mm diameter. Just another option. Not sure of the thread insert pitches available that they do make. M10 and under I sue a special tap that has a pilot to guide it from the bore to keep it concentric if required. Sometimes I use the carbide small threading tools, but they only have a very limited reach, hence for the pilot tap option.

I found it a great read.

It does pay to measure the ID of the bearings. Some can be either 0.02mm larger than nominal diameter, while others can be 0.01smaller than nominal sizes for the no name brand bearings. Been caught by that one just recently, and fortunately the shaft was oversized for the oversized bearing and then needed to be skimmed for the new brand name bearings to fit.

What is the spindle taper system? I made some ER20-ER11 adapters and they work well, as the router spindle is ER20. I would look at getting what ever fits the mill and find it with a 16mm bore to hold the ER11 chuck. The advantage of making your own is that if done between centres, you will have all the main taper in alignment. Then you can orientate that into the mill, and cut a reference inner hole. Then use that to bore the ER11 inner taper and then cut the ER11 thread concentric to the taper. I have purchased cheapy collets that were junk, so then bought some very good ones that are really great. Mine are sold as being better than 0.005mm tir and they are. On small cutters, it really does make a big difference to how well they work.

You can run the wheel wet in low rpm ranges and not make a mess. The water just takes away the carbide particles blocking the wheels surface. The low speed has the advantage of very low heat.

Find some PeeDee thread wires or buy their thread wire kit. Works great if you want to make thread of a known pitch effective diameter. The full form external inserts are great and I use them to size the OD of the thread form. So on a M16X2 thread, I cut the thread until the OD is Ø15.95mm. I use 0.05mm in diameter on all the out side thread sizes down to 5mm. Then I reduce it to 0.02 for below M5.

Using the tread wires you can use a full form or a partial form to create the thread. Often I will make a short section and use that as the gauge for cutting the ID of the other thread, like a M20X1.5 for a nut or something. If making a thread gauge, I then make it +0.02mm to +0.04mm larger than the nominal diameter. So a M20x1.5 gauge would be 20.02mm to 20.04mm on the outside of a full form thread insert. Then when you cut the M20x1.5 and make it Ø19.95mm , it will definitely fit.

At the end of most threads I have a run out thread relief area. That makes it a lot easier to stop at the end of the threaded part.

Neil

Is the file for this gear available to others for printing? My son has printed gears with a carbon reinforced nylon, epacf30 , and the gears in the model rc car have lasted a very long time.

I use ATF oil. Its used in the box for Hardinge lathes. It has additive for acid and alkaline . Does not cause issues with mixed alloys like bronze or aluminum or steel. I don't own Warco machines . I buy the cheapest ATF (auto transmission fluid) I can buy. Its great stuff. Some smell really bad or strong, so I don't get those ones.

On our cnc router, we used on the main under the table lead screw a dry lube by crc. However on the Z and Y axis, I used a very small amount of the DMG mori 800 grease. Seems to work well. But mine a ball screw not Brass screw cnc. On my Myford lathe, I have put a very thin smear on the cross slide, and top slide all moving surfaces and on the lead screws. It is working very well so far.

Tug, I just finished a set of 3 pins this week with 5mm holes through. The secret to drilling the long straight holes is the very start. I used to start with a Centre drill, and they always had some wonder. These ones I started the holes with a 6mm ball end mill to about 5.5mm diameter. Then went in with a stub 5mm drill, 15 mm deep. Then went in with a jobber drill, then with a long series drill. Sharpening the drills , so that they are even cutting from both sides and carefully either web thinned or 4 facet sharpened. I find the chisel point is good as it has very low pressure required to make it cut, compared to the conventional drill end grind. These pins are from 420 stainless, so not easy to drill. We also drill about 250mm deep with 8mm holes for injection cores, and the end of the hole is required to be quite concentric to the outer diameter by 0.1mm TIR. Quite often the drilled holes are well within the runout and roundness. The last batch the holes were round to about 0.02mm-.03mm tir at the front of the hole, and about the same at the end. We have a way of setting them up and trueing the hole to the stock, then finish turn the outers to suite. When I drill those holes, I put a very small radius on the outside corners of the drill. Gives a very nicely finished hole, and often very round too. Pushing the drill or forcing the drill , seems to lead with moved holes, same with the material getting hot. It seems to me that you just can not have too much coolant and regular pecks. On the long holes hand drill with .5mm pecks, and retract every 1.5mm-2mm. I used to gun drill the 5mm and 8mm holes, until the drills got damaged and were never replaced. I prefer for long hole drilling the shallower or longer point grind of the drill, so is about 120 deg included angle, compare to the standard of 135 deg. I have never had much luck with the flatter grind angle I see on alot of the long series parabolic fluted drills for making very straight holes.

Neil

I had a similar issue when removing that same piece off my lathe. I tool the cross slide off, removed the end plate and lead screw, and gib. I placed the casting on a piece of Ali that I had, and hit the screws with a long punch and ballpein hammer. 2 of the screws undid straight away. The one that had rolled over like yours didn't. So I found an old screw driver, reground the tip to fit as well as it could . Then put the molly grips onto the shaft, and then put pressure on the screw to undo it, and hit the end with a hammer at the same time. So like a poor mans impact driver. It only took one hit and it un done easily after that. I replace the block with a Dickson holder, and have never regretted the move. I now have lots of tool holders and tools all set to be used. Only wish now that i had bought a bunch of holders when they were cheap. lol

I have used a sleeve to hold square stock. I had square brass and held it with an sleeve made from free turning 2011 aluminium. I use them like a distortion sleeve. Being round, any shape change or distortion will create a tightening effect on the bar. Being small parts, the loads were very light. But the gripping power is alot. I have since purchased a self centering 4 jaw chuck. I find that I haven not used it as much as I thought that I would, but I do use and make alot of plain sleeves , that rely on the distortion to hold the parts. Small amounts like 0.04mm or so is easily accommodated with them. The downside of a slot is it to check runout, the interruption is annoying.

If the alloy is soft, use thread inserts, like 2d helicoils and then just use your normal M4 or M5 threads. In magnesium castings we used helicoils from new. In harder alloys like 7075, then you can just use metric threads with no issues. In the softer extrusions if there is any chance of it moving radially, add some roll pins to help it lock into place.

I have the switch go towards the tail stock for on forwards, and towards the gears for reverse. A friend asked why this was important. I said for when thread cutting, you really want to know the direction without needing to look at things.

My sharpest knife is a folded blade from Japan. I have the water stones and a leather strop for sharpening or for touching up the edge. A light hone on the polish stone and strop will keep it sharp. So I went through my knives last night. My second sharpest knife is stainless blade from France. Then there is a huge number of knives that will not hold a very sharp edge at all. In saying that, the dullest will still shave hair, but they won't cut a tomato sideways without holding it down. The Japanese knife will, and so will the French steel knife. all others won't. The other test is the sharpest knife will cut a loose tissue, all others won't.

Great stuff. Thanks for taking the time to post and take pictures etc.

I have used the sunnen external hones. I used them hand held and had the carriage well clear of the work piece. I use light pressure and oil at the same time. Of you use too much pressure, yes it will grab. But you will know when it's going to grab by the resistance you are feeling. The sunnen ones have another piece that puts a little bit of pressure/preload on as it being used. Like bore honing, their is a definite skill or technique to be able to get the best out of them, despite the sunnen flyers saying that you can used unskilled labour to make round holes or round shafts. With care you can get down to microns of roundness or even better. You can feel the out of round condition, and there is a large stone selection, for different types of materials being honed.