Member postings for Jim Guthrie

I found the same problem initially with my KX1 where I wanted to use small diameter mills and the recommended spindle speeds were much higher than the KX1's 7000rpm. But I found a feed and speed calculator which allowed for wide spindle speed ranges and I used it to calculated feeds and speeds for the typical mills I would be using - 0.5mm - 2mm carbide slotting cutters. I can't now remember which piece of software it was since it was quite expensive and I used it on its 30 day trial period.  But I've just found another calculator online which allows the the maximum spindle speed as a parameter and that might be worth a try.

**LINK**

I still had to do a bit of experimentation and it got a bit expensive for a while with the ends of small carbide bits pinging off during cuts. But I've now got a set of feeds and speeds which give me a reasonable life from the cutters.

Jim.

Edited By Jim Guthrie on 03/07/2019 09:08:54

Roger,

My ML10 is about the same vintage as your father's machine - 1973. Here's a picture of the belt tensioning arrangement on the machine which is as original. The central nut acts on left and right hand threads on the threaded arms. The operating arm is still there on your machine and the original linkage might be hiding away in a tin in the workshop somewhere.

The setup could act as a clutch of a sort but would not lock in the slackened position so you would have to have used one hand to hold it which would limit what you could do. Perhaps you father's modification was to give a locked open position.

Jim.

Edited By Jim Guthrie on 03/05/2019 17:07:48

Mine cost just over £100 in 1973 (Ted Heath's three day week year) and I remember that the price doubled when I added in the three jaw, four jaw and Jacobs tailstock chuck. So that's a fair bit of inflation given that my lathe was the original plain bearing version and your 1981 version probably was a Speed 10.

Jim.

Jason,

I used a feed and speed calculator some years ago to get the optimum feed speeds for my small diameter cutters. I can't remember which actual program it was but it certainly cut down my cutter breakage - before that it had been an expensive exercise finding out the hard way. I've just had a look at another feed and speed calculator available online and for a 3mm diameter cutter with a max spindle speed of 5000, which were your settings, the feed rates are well down into the low hundreds. It doesn't cover plastics but I usually double the feed speed for brass or aluminium. The problem with plastics is that a calculated high feed speed is useless since the material will melt, or just distort in front of the cutter. I do a lot of machining of thin styrene sheet and that can happen. The plastic sheet can also lift with the spiral action of the cutter, overcoming your method of holding down.

https://littlemachineshop.com/mobile/speeds_feeds.php

For my small size mills I am way out of the manufacturers' specs since they expect me to have a spindle speed well into five figures.

Jim.

Edited By Jim Guthrie on 01/03/2019 08:33:23

That's some feed rate. The highest G0 rate on my KX1 is 1000mm/min and my G1 rate rarely gets above the low hundreds. I work mostly with small cutter sizes of 0.5mm to 2mm and with a max spindle speed of 7000, feed rates tend to be in that low region. I'm just trying to visualise my KX1 working at 2500mm.min.

Jim.

Edited By Jim Guthrie on 28/02/2019 22:42:33

Edited By Jim Guthrie on 28/02/2019 22:43:01

Jason,

If this was the problem machine which might have been messed around with to some extent, then one thing to check would be the taper gib in the head. If the gib has got end play then it can lock the head up when travelling fast in the up direction with the wide end of the taper to the top of the column. That's the way it is in the KX1. That gib is the one thing I curse in the KX1 and it gave me a lot of trouble getting it right when I decided to try and adjust it some years ago. You're fighting the weight of the head, the nod of the head and the gas strut to get it right and I found it very easy to get it wrong, causing the head to be either too loose or too tight. I often wondered why I couldn't have a nice parallel gib strip with multiple adjusting screws. It might also be worth checking if the gas strut is working since that will put an additional load on the head drive if it is not.

Jim.

I would agree. I think that was the way John set up the original Mach versions, basically to avoid a new (to CNC) user getting embroiled in some of the finer points of Mach3 setup. I know that I found myself in deep doo-doo when I downloaded another version of Mach and I have always kept the original Seig DVD installion disk with the setup files handy. John's son Adam also did a set of screens for Mach 3 which were an improvement and I'm not sure if these are readily available today. IIRC you purchased the screens from Adam and he set them up to show your name in the profile box in the bottom right corner.

Jim.

Neil,

The nearest I get to hand operation is to use the MDI interface in Mach3. I use that quite often to do simple cuts and facing. Once I get into the swing of it, it's almost as quick as using handwheels. I've got a Centec 2A in the outside workshop that's hardly turned a wheel since the KX1 arrived.

Jim.

Ketan,

What about spares for the existing machines? I have had occasion to get a replacement drive belt for my KX1 a couple of years ago and I would be interested to know where spares might be obtained in future.

I note that John's support forum stopped working a few months ago and I suspected that someone had turned it off.

Over the last nine years I have found the KX1 very reliable and from the traffic on John's forum, it would appear that there weren't all that many problems from other users.

The KX1 and KX3 must have been unusual in the UK in having, effectively, a supplier supported user forum. I think most people purchasing hobbyist machinery depend on more general forums on the internet for any ongoing support they may require.

Jim.

I got a 3D printer last November so I had to learn a 3D CAD program to make any decent use of it. I had been reasonably proficient on an ancient copy of Rhino but that stopped working under Windows 10 and the upgrade price was quite steep for my pocket.

So I chose to go with Fusion 360 after looking at a few others and the learning process has been close to head banging. The video tutorials on Youtube have been a help and certainly give a good overview of what is achievable with the program. But when I actually got down to drawing up my own designs I found the videos of quite limited use since if I wanted an answer to a specific problem, trawling through hundreds of videos to find an answer was impractical. So I found that typing the problem into Google and looking through the answers became my main method of learning - the Autodesk Fusion 360 support blog usually came up with an answer. Or I just thrashed around in the program itself to see if I could hit on a solution.

I now feel I'm getting somewhere but it took several weeks of banging my head against a wall until I started getting results. One thing I am finding out is that its parametric rules can provide some peculiarites in 2D sketching which I've never found in 2D CAD programs so I'm having to find ways around them. But I'm getting there.

Jim.

Edited By Jim Guthrie on 02/02/2019 11:28:37

Edited By Jim Guthrie on 02/02/2019 11:29:02

James,

I've got an ML10 and I keep an eye on the prices of them just to make sure that my daughter knows what price she might get after I've moved on. For an ML10 with a good set of accessories (3-jaw, 4-jaw, Jacobs, etc. ) and with motor and lathe on raising blocks and a drip tray, around £500 is a fair price. If you have more accessories - like a vertical slide and fixed and travelling steadies, then you could ask for a bit more, or you might try selling them separately. I saw somewhere recently that ML10 steadies are like hens' teeth so you might get a very good price for them. However you might hit Ebay on a good day and get a lot more if you get two or more bidders really interested.

Jim.

Mine is the original ML10 bought in 1973. The motor pulley is 2 1/2" overall diameter and the countershaft pulley is 7" overall diameter. The depth of the V belt groove is 7/16".

Jim.

Edited By Jim Guthrie on 06/08/2018 12:58:59

But Microsoft don't have the advantage of charging over-inflated prices for hardware.

Jim.

Neil,

My point was that his tools for use on the lathe - at the bottom of the PDF pointed to - were the same design as the Eccentric tool-holder. I remember seeing the Fonly and its tools being demonstrated at the London model railway exhibition in the 1980s and I always meant to make some of the toolholders to use on my lathes, but never got round to it.

Jim.

The 2mm Society got there over twenty years ago.

**LINK**

Jim.

Edited By Jim Guthrie on 12/07/2018 17:56:41

Robin,

I answered a similar question about a year ago.

"The two open ended spanners supplied with the plain bearing ML10 were

1/4"BSW:5/16"BSF + 3/16"BSW:1/4"BSF

5/16"BSW:3/8"BSF + 3/8"BSW:7/16" BSF"

Jim

Arc do a 4" rotary table as a plug-in (the 6" version would be a bit big for the KX1)

https://www.arceurotrade.co.uk/Catalogue/Workholding/Rotary-Tables/4-Rotary-Table-with-Stepper-Motor

I've got this part and it does work very well.

The prices really have shot up - getting nearly double what I paid about eight years ago and I got Mach3 and Cut2D bundled in the machine price.

Jim.

Edited By Jim Guthrie on 25/06/2018 09:24:42

Don't forget that the apron handle on the ML10 doubles as a thread dial indicator and you might have to make alternative arrangements if you need this facility.

Jim.

I don't think my RSU works at anywhere near 100 amps. Certainly the cables and plugs and sockets used would never carry anything like that. I just did a check and the resistance of the lead with the carbon rod is about 0.4 ohms so with a voltage of 4.5V, that would give a maximum current of about 11A. I never normally work at that voltage because there would be a danger of burning holes in thin gauge metal. I normally work using 2.5 - 3V on metal gauges of 0.010" and upwards. For any metal thinner than this, I would drop to 1.5 to 2V.

Jim.

Edited By Jim Guthrie on 04/06/2018 21:02:39

I don't think there is much electronics involved in an RSU. It's basically a mains transformer with a tapped, low voltage, high amperage secondary providing the variable power settings by selecting from the tappings. The one I own has a 4.5v secondary with two intermediate tappings which gives six permutations of voltages up to 4.5V AC (measured using my meter so not peak to peak). I believe the power switching is done on the primary side of the transformer using a relay. I think the problem will be sourcing a transformer with a suitable secondary winding, or else wind one yourself.

I believe that some people have used power sources like a transformer from a six volt battery charger to do the job but with no tappings you then lose the ability to reduce the power for finer work.

Jim.