Member postings for Neil Lickfold

You can reduce the burrs being created by using a smaller cutter and have it with the cutting forces into the work piece edge. ie, a piece that is 20mm wide and 100 mm long, could be faced with a 25mm diameter cutter, but the larger cutter will most times leave a burr. If you use a 12mm cutter and approach with 2 axis till the cutter is just past the 1/2 way part of the work piece, ie 10.5 mm from 1 edge, it will cut clean mostly with little to no burr at all. In industry there are many times where a clean sharp edge is a requirement of the part being made.

Neil

You don't want Brass guideways. I assume you mean gibs. You could do the Turcite B slideway material to the one side of the gib strip though.

Neil

Many years ago, about 1986 I brought one of these. http://www.blakemanufacturing.com/pages/aboutus.html

It is the coaxial indicator from the Blake manufacturing company in the USA. While not as accurate as a 0.002mm DTI, it is very fast for centering up a hole. With the spindle running you can quickly move the axis around till you get the least movement on the dial and get a zero position. I brought the carbide feelers for it early on and was glad I did. I run it at about 120 to 160 rpm, what ever is the closest on the belt arrangements or gear box. I found it to be particularly useful in horizontal work where it is difficult to see the other side of a DTI. The only downside is that they are a little long though. There was another brand available at the time, a little more shorter on total height, but was a lot wider and bulkier to handle.

Neil

I made a few counter weight blanks for my model plane single blade props. This is the ER40 collet set up I made and can use a variety of stops. In this case I made a stop that is 0.02mm smaller than the shape of the blank. It holds onto the 25mm od that only has 0.2mm length to hold the part for the 2nd op. The 5.98 mm spigot helps to stop the part from walking out.

Neil

I'am not sure of your experience in cutting plastics. But if you go too fast you will melt the material to the tool. Sometimes it is best to use a narrower tool that is sharp and with the final corner radius detail. For a 5mm section O ring the groove will be about 5.5 mm wide and about 9.3 mm deep on diameter. A tool made that is about 2mm wide and about 5 mm out at that width will work well. When the tool gets too wide, it creates a lot of chatter on the work piece etc.

Neil

I am in Hamilton and it was felt here. A friend lost about 1/2m of water out of his pool just filled in the weekend, about 18 inches in real measurements. The lights were swaying at work this afternoon from an after shock. On the news they just mentioned that the fault area is about 100 km long, so one of the biggest known for here in recent times.

Neil Lickfold

Cast Iron makes for the best indicator stands as it generally has the highest amount of rigidity . The mentioned indicator I think is for comparator stands for comparing components and not to be used as an indicator in a lathe for example. For a part indicator I have always brought the ones with the very low pressure stylis. These have the least deflecting influence when indicating parts to as high a precision as you can. A lot of indicator stands actually will not allow you to indicate a part to 0.01 mm TIR as the indicator stylis load and stand flex is such that it can not actually be achieved. Once you start to getting to less than .01mm it really does take a lot more attention to detail especially when you are in the 0.001mm range. Less than 0.001mm is a totally different world to be working in.

Neil

Roy , I make my carbide drills similar to the sandvik ones in the link here,

https://www.amazon.com/Sandvik-Coromant-Carbide-Uncoated-Straight/dp/B005FXF76Y

I use air to keep flushing out the micro chips and on the small ones under 4 mm use about 800 to 1200 rpm and hand feed normally in as ridgid as I can drill or mill. I cheat and increment the feed stop each cut about .1mm at a time.

Neil

It all depends on the Mill. Some have LH leadscrews and some have RH leads screws. Neither is wrong. I have seen geared cross slides on mills, where it is 1:1 and then 10:1 to get the precision. A lot of machines with Ballscrews with a clockwise handle turn brings the table to the operator, so the cutter is effectively in the plus direction from the operator. Similar on the LH end of the mill, a CW handle movement is the Cutter effectively in the positive direction.

Neil

The Cox model engine maker used to make their engines so good that any piston could fit any bore if it was new. They were the exception for a long time. Neil Wyatt has hit upon a very important part in manufacturing. The service fit is far more important than the actual size in most cases, especially with a home built 1 off project. Making a piston to fit a bore is far easier than making a bore to fit a piston. Went through some old drawings from the 1960's for injection plastic moulds. They used both fractions and decimal inches down to 4dec places. On the parts that mattered it had a statement like 0.0002 clearance fit, or 0.0003 air vent etc On fraction dimensions they were to 1/64 inches unless otherwise stated. Nominal 1.0 inch dimensions were to +/- 0.01 inches, 0.01 inches +/- 0.002 0.001 inch +/- 0.001 inches all these were unless stated. So the drawings have notes all over like FIT or 0.0015 clearance etc.

Now days it is all metric with the ISO standard of fits and clearances , but on important parts, there is a note about the Fit or the detail pertaining to that part for it's function.

Neil

From what I have seen, it is ok to use fractions and decimal inches. Important dimensions are usually stated in a note the particular important dimension. The overall is normally like been mentioned before by others.

The only difference I have seen is that on 4 decimal places the tolerance would be +/- 0.0002 unless stated.

Anything with 5 decimal places is always stated. Like in metric, anything to 4 decimal places is always stated.

Neil

If for what ever reason the part does not shine, you can use white or grey fine scotch brite to polish the parts while making almost negligible change in size. There is also wiper inserts for turning as well, these effectively burnish the part as it is being cut to both improve surface finish and allows higher than normal feed rates. Depending on the part profile etc, you can make simple wood Vee blocks, and use double sided tape to hold various grit paper to polish and keep the part round. Like starting with 400 grit then 800 etc to 1200 or 2000 paper. The grey scotch brite is like about 800 paper or so ,the white is like 1500-2000 paper or so.

Neil

You don't need high surface speeds to get a good finish with ali.

I only run my Myford in the low range of the motor to the top pulley. I think my fastest speed is in the 600-700 rpm range. Sharp tools is really important and then finding a lubricant that reduces or prevents the ali sticking to the turning tools. Lately I have been using Rice bran oil and seems to be really good. Just make sure you clean up afterwards though. I cheat these days and use the Ali/ plastic turning inserts for most things even on bearing steels.

Have fun and learn what you can. With Ali and plastics and woods, you can not have the tool too sharp, but at the same time, don't make the angles too steep on the top rake if you are grinding your own HSS tools. Honing or polishing the top surface with a Cratex or some other polishing tool before you grind the side clearances is a good thing to do as well. But I now mostly use the nice carbides but that was if you are grinding your own tools.

Neil

In the past, I have made D bit gear form cutters when we had no gear cutter at the time. It was quite easy to make as it is only 1 side of the profile to be produced. It was for a 1 off job and worked well enough at the time.

Neil

When possible I like to thread cut with the compound slide set at the angle of one side of the thread being formed. In the case of a 60deg UN or metric thread that is 60 deg from horizontal or 30deg from inline with the cross slide screw. I set the compound slide dial to 0 and then use the cross slide for the initial touch off on the stock diameter. Some trig is required to get the thread depth but that changes with the nose radius of the tool. I find with the full form threading inserts, if I leave the threaded area a little larger on diameter, I can keep cutting until I have cut to the marker pen. Then measure the diameter of the stock and then make the thread untill the stock diameter is about 0.05mm smaller than the nominal thread. Ie on a M10 thread, I leave the material at 10.1 or 10.2 mm diameter and colour it with a red or Blue marker pen. At the end of the thread length I just wind out the cross slide. Reverse the lathe spindle direction and as it goes back, I put the next 0.05mm or 0.1mm cut on. Re position the crosslide back to the original zero point and keep cutting. Now that I have the VFD and 3 phase motor, thread cutting is even easier as I have a limit switch that stops the motor at the same distance point every time. Normally better than 0.02mm on the main leadscrew dial of my Myford Super7. Where ever possible I have a run out area that is undercut to the root diameter of the thread for about 1 to 2 pitch lengths long. So on the M10 I would have an a length that is relieved about 2 to 3 mm long. On internal threads I usually use 2 pitches to give myself more lee way as to the outside threads which are more easy to see where the tool is. Most of the time I leave the leadscrew always engaged. Only when doing multi start threads , I leave the compound slide horizontal and then do all the thread depth on the cross slide dial. I then feed on the compound slide the thread pitch for the second or however many start threads it may be.

Neil L

That is a stainless grade insert. What are you mostly cutting and how much power do you have with your lathe?

In that DCMT11030X range is a very big variety of insert chip breaker /geometry, nose radius, and coatings. Some of the coated inserts for stainless do very well for home workshop use, especially the ground ones like what you linked to in your OP. Others are not so sharp , and require more power to create the shear and to generate the swarf as chips. Making long strings is not what the inserts are designed to do. Keep in mind most are for use with industrial production machines with feeds and speeds and depths of cuts that create chips, even on the finer finish paths. That is why they make so many geometries and grades in the most common of tool holding styles.

Neil L

If you want the holes round, getting them honed with a proper hone is fairly quick and simple to do and may not cost very much to have an experienced honing person to do the job for you. Reamers in that size are not cheap and the offset reamers that do make round holes will be very expensive just for the 2 cylinders that you are making.Home made laps can work well , but like everything care is needed and you really need a bore gauge or something similar if you want them to be a specific size or roundness.

Neil

If your chuck is a key type you probably can get away with i for small cutters. If it is the keyless type , no matter what size it is I would sat no.

It does have a chip breaker on that insert, but is the wrong one for that material choice. We have lots of inserts at work with different chip breakers for this reason. As one does not do all very well. The DCMT CCMT and the TNMG range of inserts also have the best range in chip breakers. There is a valid reason for the insert makers to have such a large selection of inserts. I do alot of O1 turning in both soft state and hardened state. It is essential on a cnc to get chip control. Long strings only lead to tears. Which is why I suggest for the home workshop the best compromise is to only get finish turning inserts and not the ruffing out ones.The radius to get is either the 0.2mm or 0.4mm radius inserts. Most home machines just don't have the power or rigidity to properly run a 0.8mm radius insert or bigger. For hard turning O1 I use either ceramic inserts or CBN inserts. Some jobs I have to use CBN as the ceramic does not come in a small enough radius. With Ceramic inserts run at surface speed of 90 to 180 m/min and a depth of cut from 0.05 to 0.5 or Ø0.1mm to Ø1mm at a feed rate of 0.06mm or 2 thou per rev. Ceramics wont take interrupted cutting.

Neil

Video of making a boring bar, he is using the wrong chip breaker insert for that material. It should be coming off in chips, so the issues are either wrong chip breaker, wrong depth of cut and wrong feedrate. Being as it is not a really powerful lathe, he is taking small cuts and the tool geometry is therefore wrong for that particular material and job.

A finishing insert designed for small depth of cuts would have been a better choice. Most finishing insert geometries are for taking to 1mm depth of cut so are ideal for home workshops and lower powered lathes,

Neil