Member postings for Neil Lickfold

For your spec,the only option is to gundrill, then put it between centres and then turn the out side true to each end of the hole.

If you want to drill it, like above, predrill and bore for about 1.5 diameter long, in your case 20mm hole X 30mm deep. Then with a chisel point sharpened drill, 175 rpm at .05mm to .06mm feed per rev feedrate, about 8 to 10 mm per minute, and 2 to 3 mm per peck distance. This will give you as good a hole with a conventional drill as can be achieved. I just put the drill just straight down, no pre drilled smaller hole. Have the work piece setup with a steady to support the front . Then after drilling through 1/2 way do the same again from the other end.

Neil

With mine, win7 , there is an option to look at what is down loaded offline. It brings up a warning, but only means that while offline, new content can not be downloaded.So instead of choosing yes, I click NO, then it opens to a blank screen.I goto downloads and then can read the downloaded magazines.

I regret not getting the printed version. The digital version is not as user friendly as I would have hoped for or liked.

Neil

Jacques,

So if the sliding tool holder was set on angle, would it then be possible to turn tapered threads?

Have you got pictures showing your setup without the chip cover ?

There is a couple of reasons, 1st to look at is the Ph of the coolant. If new coolant still does the same result, it could well be an electrical issue with you mill . A bad earth or insulation breaking down and creating electrolyses.

Seen 1st hand what happens when a motor windings have the insulation breaking down. Even though you do not get an electrical shock, there is current running through it causing electrolyses.

Neil

When I drill capscrews, I drill quite slow, a 5.1 or 5.2mm drill I would use about 220 to 300rpm range and keep coolant or oil on the drill. If the oil smokes, I slow the drilling speed down.

Neil

There is carbide drills these days that will drill holes in steel to 58 Rc, failing that, it can be easily edm drilled also.

Neil

My rule of thumb for ruffing is max depth of cut is 5 times the radius, and a feed rate of 1/2 the radius.

For finish cuts, I use 1/6 the radius for a fine finish, for general finish I use 1/4 radius as the feed rate, and depth of cut to being genrally 1/2 the tool radius.

Some lathes do not have the power or rigidity to run these ruffing numbers with anything bigger than an R0.2mm cutter.On my S7, I use R0.2mm TNMG tools, with 4340 or 4140, cut depth is 1mm on radius, 2mm diameter, but only a feed rate of 0.004 inches, about 0.1mm per rev. For finish passes , I use 0.2 to 0.4 mm on diameter. RPM wise, I think it is 690 rpm or so, the fastest on the slow pulley. As for a coolant, I use cooking oil.

Neil

I needed a new digital calliper, so this time I brought a solar powered one, that does not need a battery to be replaced. Some told me that they don't work well in low light. So far, the light level that won't make the calliper work, is not enough light for me to see what I am doing anyway.

I really like it.

Neil

Hi Chris, we used to have tangential threading tools and parting tools. They do work great and are easy to resharpen. What I like about the carbide stuff is I can have the heights on the tools set, and then forget. I have 3 lathes all with dickson type toolposts and all tools will interchange on the centre heights. No need to adjust tools from one machine to the other.

Neil

Facing to the centre is what damages most tooling cutting edges. So if it does not need a flat face, I drill out the very centre and put a dimple in the face, either with a ball end cutter or just a centre drill start.

Insert tooling is very convenient, and I find time saving. There is a new series of 1.5mm wide parting inserts that are well suited for lower powered lathes,and groove to 20mm deep Ø40mm

The reason I chose the TNMG is for the vast range of available inserts, for cutting plastics , Ali, etc all the way to any exotic material that can be cut. There are also Ceramic inserts , so turning of hard materials becomes a reality, instead of grinding.

I have found that cheap, and cheap holders, actually expensive inserts and holders. The initial price seems good but they often do not last very well or they have a poor geometry or poor insert pocket quality.

I have hss tooling as well, but very rarely use it now. I only make form tools from hss these days and then only if I have too.

Insert threading tools are really great, especially the full thread form inserts.

Neil

Not sure how to edit, Some corrections.

My holder I am using for the TNMG tool holder is not a genuine Dickson, but has a thinner bottom flange, Also, the centre height of the tool is actually 8mm, not 9.5mm as posted above. So 4mm was removed off the bottom face of the insert holder.

Neil

I recently brought a Kyocera brand holder that take these inserts, TNGG160402R-S PR1125,

the grade and coating is PR1125, it is a 16mm insert , 4 mm thickness, and is a 0.2mm radius (.008 inch aprox) This series of inserts have a corner radius from 0.2mm to 0.8mm .These seem to work well on a variety of materials from ali 2024,7075,6061,2011, to plastics to steels, 4140,4340 is what I have used with it so far.

The tool holder I brought was, MTJNR1216K-16 Right hand, it has a 12mm centreline height, but had to get the underside trimmed down to get the tool height to 9.5mm (3/8) to suite my Dickson holder.

What I like with this is I get 6 edges to use per insert, they are well priced as they are widely used in industry, and this size has the most variations in cutter geometry, and coating technologies.

Neil

My advice is to buy the Bearing collet nut. They have a bearing so the front taper does not rotate with the nut.They cost more ,but once you use them will not go back to a standard nut again. It allows a higher clamp force as well as it makes it easier to have the collet to stay in the same radial position.

This is useful when you have made your own collets or have a collet that has been retrimmed in position to get the highest possible concentricity.

I like the ER40 collets, but like the price of the ER32 collets. I have a home made spindle for a Taig type lathe and made it to take the ER40 collets. The larger nut means, that for most things, I can hand tighten the nut with the need for the spanner.

Neil

I fixed a digit calliper in the same manner, but used electrical contact cleaner and also found that the rubber strip had moved slightly. I suspect it had been dropped to cause this. I cleaned it all and placed it back into the correct position.

The symptoms were not displaying all the digits correctly, intermittently went out or showed error.

Neil

A great picture.

I have had one of these belts on my Myford since 2006. I only put it on the outer like you have done as I was not sure of the life or consistency of these belts. When the spindle belt starts to look sad or slips, it will be cutting it off and be replacing it with the sectional belt. I got a piece for the job, but have not got to replacing it yet.

I just could not get over how much it reduced vibration and the surface finish improvement.

The spindle belt was replaced with a Gates belt that has the notches to allow it to bend around the pulleys easier. It has lasted way longer than expected. That belt was replaced back in 1996 or so when I rebeded the front bearing and replaced the rear bearings.

I have not experienced the spindle belt slipping, and do not see the need for a poly Vee belt. But I am also not against anyone making such changes. Each to their own.

Neil

Power feed tailstocks etc, in my experience, is only good for processes that do not require pecking, like a roller box or a gundrill, those sorts of things.

I am not aware of any particular seller of these spindles to avoid. I have not heard any bad sellers. The person I got this spindle from, was offered a replacement, but decided to get another brand of spindle at a considerable cost increase. The runout is about 0.02mm or so , maybe .03mm not a lot but it is on small cutters.What I like about the ER series of collets, is they are easy to make at home. An important and often over looked is the thread on the spindle for the nut ,must run concentric and true to the spindle taper.

There are different series of precision collets. Big from Japan ,make some of the most accurate ER holders and collets available. They have a series that they claim 1um at the spindle nose of the collet with a test piece.

They make a modified version that has more of the 8 deg taper engaged compared to the standard er system, and a much improved clamping nut design. Their precision collets only have a 0.5mm range, instead of the usual 1mm size clamp range. Some really good info in their PDF to download.

http://www.bigkaiser.com/hsk-er-grip.php

Here is the link to their site and their info.

Neil

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

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

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