Member postings for Neil Lickfold

Good points Murray. The screw cut retraction units I have seen have too small a stroke for what I need. The lever I am going to adapt initially will be about a 10:1 on the current lever, but have not worked out the total ratio of lever to slide movement. I am thinking it will be 30:1 per side. It will work fine for what I want.

Another suggestion was to put a stepper and micro switch stop with auto return to the retracted position. But that won't happen unless I need to make a lot more than is anticipated. It may then be an option to just get them commercially made on a cam auto or some other simple production machine.

Thanks for the replies and input.

Neil

Thanks Dave,

At this stage I am going to buy a small slide from someone who has decided to kindly part with one that they have.I will be able to adapt it so as It becomes a rear part off tool from the back side of the cross slide. I only need to make a lever adaptor to be able to reach it all from the front and a simple plate to put a small Dickson QCTP onto it.

Neil

All my D bits are cut to centre line. The outside is clearance to within about 0.05mm of cleaning up the cutting edge and backed off. Depending on what I am doing, the back off is anywhere from 10 deg to 25 deg. When used in a mill, hold the tool as close as possible to the shortest amount to do the job. I have used D bits for a variety of work. From a precision tapered reamer effectively, to a combination drill and boring tool. Or as the new cutter companies sell a MDT, multi direction tool. I do use a D bit grinder for making them and take from 10 mins to 3 hrs depending on accuracy and geometry etc. I make most from micro grain carbide.

Neil

There is also live tooling for making threads. It consists of a router mounted on the lathe tool post and a single row thread milling cutter with the thread angle on it, ie 60 deg included. These typically are short threads so about 20mm long is normal depending on the size of the cutter. These are effectively cut on a lathe in a similar way to thread milling on a mill, ie in 1 or 2 passes at a fairly slow rate, about 50 to 70 rpm, for both inside and outside threads. As the cutter is not inclined at the correct helix angle, it does not create an exact true form, but is good enough for a nut and bolt. There are for mills, multi thread cutters, that cut an entire thread length ,inside or outside in 1.5 turns of the work piece, or around the work piece which ever the case may be. A lot of people who do very nice wood work and work with Ali, like to use the live tooling method for thread generation. There are also full form live threading these days as well. In industry, a lot of threads are rolled with rolling heads, even into Stainless steels, etc. They also have special heads that effectively knurl splines and gear forms as well. But the rolling boxes as I call them really aren't in the area of a hobbyist. The live threading is though absolutely. Screw cutting is very popular in job shops or when there is only a small run of parts and the other threading methods are just not viable for the number being made. I recently saw a Titanium part that was solid 3d Printed with an M14 fine thread and it worked fine. I was just blown away with what I saw. 2 years ago, the thread would still have needed to be chased, or a die nut of some sort run over it. I have hopefully attached a needle and body that was all made on a small cnc mill. The back of the needle was set up and parted off the bar. Even the M4 thread was live thread milled. In theory, if I could model good enough, I should be able to make these parts on my CNC router, but don't bother as I am good on a lathe.

Edited By Neil Lickfold on 31/12/2016 11:13:01

Andrew, for me, I brought the holder that takes the 16mm full form threading inserts. There are only a few needed and they last a really long time if ya don't do stupid stuff with them. I get the full form and keep threading untill the OD of the thread form is at the diameter of the thread required to Ø0.05mm smaller. So I have 0.5,0.7,0.75,0.8, 1.0,1.25,1.5,1.75, they cover every thing that I want. Anything in between like the whitworth form, 55deg, I just use HSS as I do very little of those threads. I screwcut with the compound set at 1/2 the thread angle, so UNF or Metric I use 60 deg from horizontal. I in feed on the compound slide and leave the cross slide at a fixed position. This way, I don't need a nicely full formed tool, I only need the leading edge of the tool to be ground at 30deg from inline with the tool, and the trailing side only needs to be the form for the 1st 0.3mm or so, how ever much of a cut you take per pass. The trailing edge becomes generated, not fully formed. I leave the leadscrew fully engaged for the entire time of threading. Now days I have VFD and 220V 3 phase motor and a microswitch that stops the spindle at the end of the thread pass. I undercut the thread form end on both inner and outer threads and generally use a radius tool when doing this on OD work and just a simple groove/ oring type groove tool for the inner threads. Where possible for inner threads I use a tap, unless it has to be a precision thread then I will screw cut it, or if it is on the larger side , ie M16 and above.

For 32 tpi UNF I use the 0.8mm full form, 24 TPI, use the 1.0 mm full form,and for the 20TPI I use the 1.25mm full form.These have been the most common threads apart from the metric ones that I cut.

Full form inserts can be brought for about,$NZ 10 to $15 including tax. Cheaper from Asia if you want to wait however long to get them.

Smaller internal threads I use either a carbide internal threading bar used in cnc single point threading, or make my own from HSS. Internal threads, I use the compound slide generally at Zero and just infeed on the cross slide dial, and effectively full form thread. I do this because I preset the micro switch to a stop and then feed on the compound slide to the thread end point safe zone. This way I do not crash the threader into the end wall if it has one.

Neil

The closest I could find was scarce info on the Brown &Sharp #10 collets, but they are not the same as the MA99E collets. I have asked Myford so we will see.

Thanks Neil

Michael, clearly you totally miss understood my initial post. I know they exist, I have a few. I am after the data sheet for the collet specifications, just like you can get the specs on ER32 collets etc etc. But that same data seems to be eluding me and all the searches come up zero. I don't want someone else to make my collets, I want to make some very specific collets. I just want the specification for the the original collet design. So far non of your links etc have shown any specifications for the MA99E collets.

Neil

Michael, those are also things that came up, but no specs given to the collets actual outer conforming dimensions.There is no shortage of people selling , and most is available, except for the sizes I want. They don't make an emergency collet either in the MA99E. Emergency collets are all made, ie slitted,and have 3 or 4 pin holes , where dowels are fitted, and then the collet bored or cut to the required shape etc.

Neil

Hi Allan, I have a friend with a Myford super7 , he is also in Papakura. Send me a PM and I'll see if Bill is near by and may be able to share knowledge between.

Neil Lickfold, Hamilton NZ

The Hardinge website does not even mention MA99E collets. Google only comes back to this page because of the mention of MA99E collets. Nowhere have I been able to see a drawing or any reference information on either the collets or collet holder. I am sure that the taper is 15 deg per side and that the register diameter is Ø23.98 mm from measuring the sample I have. It looks like the front nose is a nominal Ø22.0 with a 5 mm spigot length. The outer diameter of the collet taper looks to be about Ø29.0mm if projected to a sharp point. From the collet front shoulder to the back of the collet looks to be a neat 54.0 mm long and 59.0mm long over all. While what I have measured will make for me a working collet, it would be nice to know what the real spec actually is.

Neil Lickfold

Does any one know where the specifications can be found for the Myford MA99E collets ?

I have a few collets, and want to make some special sized ones. I have some existing 1/4 inch and 16mm, but am wanting a 3/4 inch step collet and a 3/4 inch through collet.

Thanks, Neil Lickfold

Thanks Andrew, PM replied to.

That's perfect Andrew. I sent you a PM message.

John Haine, I will be using a tool in a fixed position with the tool post and want a sliding grooving tool.

Let me know Andrew,

Thanks, Neil

Thanks for the other suggestions. I want a system that I can leave the cross slide in a set position or one of the operations, and then I can feed the carriage along a set amount, in my case 2 turns of the feed when and then groove the part. It will have about 9 grooves per part. The groove depth is not that critical. All the lever stuff I have seen is usually in a fixed position, although it can be positioned along the bed, is still fixed. I cam across a cam design for thread cutting, but is too short a stroke, but all the ideas are there. So I'm thinking of using some pins and bushes instead of a dovetail, and also having the sliding block very close to the base block.

Yea, Im looking for something on the cross slide or tool post mounted. I got a series of parts to make,and they can be really easily made if I have a fixed cross slide position, but use a lever or cam operated sliding something with the 1mm wide parting tool moving radially about 15mm of movement. Saves winding a handle. Maybe an air cylinder and velocity valve may work also. If I find something or make it, I'll post back.

Andrew, have you got any info like size etc of the Pultra slide?

Are they still available and how much are they? Do you want to sell one?

Thanks very much, Neil Lickfold

Thanks all for the replies. It looks like none are available as an off the shelf item. One day I'll make one up.

Merry Christmas everyone.

Neil

Is there such a thing for Myford 7 or similar sized lathes , that have a parting off tool that is operated with a lever or cam ? IE you do not need to move the cross slide to part off , but the parting tool is moved with it's own slide. Something that mounts onto a tool post or is mounted onto the rear side of the cross slide.

Any ideas or suggestions will be appreciated.

Neil Lickfold

The only tricks I know of is to keep it cool cutting. Ie slow surface speeds, high feedrates relatively . I treat it like stainless steel, so 1/2 to 1/3 the speed of steel but 2x the feedrate of steel. It very quickly work hardens, and I find that a geometry for cutting Aluminium works really well. There are Ti specific cutting fluids , in both neat oils and soluble oils. Carbide Ti geometry drills are really neat, but expensive of course. The coated drills last quite along time. If they are resharpend, they really are the same as a std HSS or carbide drill, once the coating has gone. When tapping, sharp taps are best. I find using series taps are better than regular taps. I find that if you keep going slowly it works better than start stop approach. Series taps are smaller in the overall diameter, and you tap in a series of sized taps. Or I have ground down the outside diameter of the tap, and then relieved the od of the tap to the cutting edge. House keeping ie tidy as you go with the chips in the tray is essential.

Neil

I have seen a chuck where 2 jaws can be set, and then locked, and the 3rd one is the only one that moves. The 3rd jaw was moved like a 4 jaw, ie on it's own scroll for that jaw.

It may have been a purpose made, as I do not recall a brand name on it. With the other 2 jaws, there were various shaped jaws that were used with it. They were made in such away that the part could not be accidently placed in the wrong way. The other 2 shoes as I would call them were often referred to as grips.

Neil

Well, I was going to make up a clutch arrangement. But in the end, I just use a micro switch on the VFD and 220 3 phase electric motor. When the micro sets off, the motor stops. I then wind in the appropriate direction to remove the tool from the work piece, hit reverse and then repeat. At about 200 rpm it stops every time to within 0.1mm I have the VFD breaking the motor to a complete stop in about 0.5 seconds I think. If you try and stop too fast you can unscrew the chuck off the spindle.

Neil Lickfold