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Member postings for John Baron

Here is a list of all the postings John Baron has made in our forums. Click on a thread name to jump to the thread.

Thread: Correct use of slitting saw for deep cut.
30/12/2019 17:19:28

Hi Guys,

I recently cut a tapered slit in a 82 mm long length of gauge plate using a 0.8 mm slitting saw with a 6.35 mm bore for an adjustable parallel I was making.


I used a length of 1/2" steel rod to make the mandrel. The thread is M6 with a tiny shoulder that fits into the bore of the blade.


The mandrel was held between the lathe three jaw chuck and the tailstock live centre in order to rotate it.


I used a simple wooden jig to secure the piece that I was slitting. I used the other tapered parts as a wedge to hold the parallel whilst I slit it. The lathe was run at its slowest speed without using back gear.



The cutting lubrication was Trefolex applied using a brush. The hole you can see through the middle is threaded M6, and is used to pull the two sides together in use.

Part of the problem with cutting a slit like this is that as the cut progresses the blade pushes the workpiece backwards and then down. As you get to the end of the cut the blade is trying to lift the work.



As can be seen it worked quite nicely, even though the blade did start to deflect as it got to the deepest part of the cut.


The two half's of one parallel showing the brass guide and the slit bottom half.


One thing that did take me by surprise was that the thin end twisted ever so slightly ! I didn't expect it to stress relief as it did, A little tweak with a mover whilst in a vise helped sort that problem. Both pieces now slide all the way from end to end.

Thread: Those little screws for carbide inserts...
30/11/2019 20:49:11

Hi Guys,

A quick tip ! To magnetise a screwdriver, just drag it over a magnet a few times.

Does not work for stainless items. smiley

30/11/2019 20:45:17

Hi Guys,

A cheap source of 2.5, 3.0 and 3.5 mm coarse torx screws are old hard drives !

Thread: Threaded Norman Toolpost
11/08/2019 12:32:54
Posted by Michael Gilligan on 11/08/2019 07:03:24:

Thanks for the reply, John

I tend to use espacenet, which has good worldwide coverage and quite flexible search criteria ... but I can try on uspto.

Several tool-holding patents are available, around that date, in the name of Van Norman, but I have yet to find the one for this elegantly simple design. ... Perhaps it is hidden within one of the others, as an alernative 'embodiment'.

[or perhaps I was just having a bad day]


Hi Michael,

I do recall that was how I discovered about "Van Norman" Lathes.

I must admit to not being able to rediscover it. If you do come across it, please let me know.

11/08/2019 06:31:45

Hi Michael,

Unfortunately not ! I did find the original info on line quite some time ago, but I've been through a couple of hard drives since then and my backups are not all that they should be. Over time I've lost a lot of information that I can no longer find on line.

Have you looked at the USA patents office ? I think you can search it by both name and date. The earliest reference I could find was some time in the late 1880's. But I'm blessed if I can remember exactly.

Thread: Slot drills in a woodworking router?
11/08/2019 06:13:19

Hi Robin, Guys,

I agree with the above comments !

It works well the other way round ! I've often used carbide router tool bits on the mill for cutting steel, unfortunately slot drills don't work in wood... though you might like the smoky smell

Thread: Threaded Norman Toolpost
10/08/2019 20:17:26

Hi Chris,

Take a look at these pictures !


This picture shows the pin after it has been split into two halves and before one half has been drilled to remove the threads.


This picture shows the above being checked for clearance before drilling out the threads in one half..

Note that the split pin is machined at the same time as the hole is being bored.


It did occur to me that you may have thought that the first picture in the original post was mine !  I can assure you that it was not, although I do admit to having looked at that design and discounted it as poor.

I have all my original drawings should you want a copy. My drawings are based on the original Van Norman 1880's patent document and not on the later modified ones using a slit and a pinch bolt to clamp the tool block. It was Norman's original design that was used by Rolls Royce in their experimental workshops.


Edited By John Baron on 10/08/2019 20:19:19

10/08/2019 16:42:04
Posted by ChrisB on 10/08/2019 16:39:03:

How does the clamping work John?

Michael Cox's collet type Norman tool post is also very interesting **LINK**

Did you bother to actually read my first post ?

10/08/2019 16:13:47
Posted by geoff walker 1 on 10/08/2019 15:53:31:

I have a Myford / Drummond M type, which uses Norman tool holders

Over the years I have added to the collection and now have 10 tool holders

I think it's a great system easy to swap and change and each one is set so the tool is accurately centered when tightened in place. The only downside is you have no angular indexing, but that's not a problem for me.

Some years ago I bought a second top slide and converted it for a dickson toolpost. I bought the tool post and holders from A & R precision in coventry. They were expensive but really well made. I've used the top slide and dickson set up about 3 or 4 times in all. The whole lot is collecting dust on a shelf. I always use the norman tool holders. I must be one of the few people on here who does not like the dickson set up.


I Ebayed mine and got about half back of what they cost me. For a hobbyist not a good buy at all.


These are pictures of mine.



My rear tool post and tool block with parting blade holder.


Edited to insert pictures.


Edited By John Baron on 10/08/2019 16:24:34

Edited By John Baron on 10/08/2019 16:39:38

10/08/2019 16:08:13
Posted by ChrisB on 10/08/2019 14:52:22:
Posted by John Baron on 10/08/2019 14:19:13:

If It was good enough for Rolls Royce its good enough for me !

But the Rolls Royce (Norman) tool post is not exactly a QCTP right? If I understand the working of that tool post, it's quick change feature is it can be slid off the top slide easily, but you need a tool post for every other tool you have, right?

You have a tool holder for each tool you want to use, just as you would have a tool holder for each tool using a QCTP. The post stays on the top slide, it is not removed. Also the centre hight is adjusted in exactly the same fashion as a QCTP using a screw. In the case of my Norman patent tool holder, a M6 cap screw, 39.3 thou per turn or 1 MM.

10/08/2019 14:19:13

Hi Guys,

I've built two of these for use on my Myford S7LB. One as a replacement for the originally supplied 4 way tool holder and the subsequent replacement expensive QCTP. The second one as a rear tool post replacing a parting off tool post that I made. The idea being that I can just swap tool holders between both back and front at will.

All the tool holders that I've made will take a maximum 1/2" tool and right down to a 4 mm square tool. Also the original Norman Patent tool holder used a split pinch bolt and not a slit with a bolt through the block. A split bolt gives better rigidity and better clamping. A quarter turn on an M6 clamp screw from loose to locked tight is all it takes.

I believe that the slit block was used to make the tool holder easier to make !

If It was good enough for Rolls Royce its good enough for me !


Edited By John Baron on 10/08/2019 14:22:10

Thread: Collet Chucks out of true
05/08/2019 21:09:21

Hi Iain,

I would double check everything, 0.08 mm is 3.2 thou that is an awful lot of runout !

I get an average of 3/10 ths of a thou at 3 inches. And that is after I've cleaned everything and made sure that there are no burrs anywhere. A clue to having a burr in a collet is tiny scratches on the work. Similar on the edges of the chuck. Check the collet for scratches.


Edited By John Baron on 05/08/2019 21:10:13

Thread: Rotary Valve engine having more than two cylinders
04/08/2019 21:27:13

Hi Guys,

I've seen an 18 cylinder rotary valve engine ! It was used in aircraft some years ago. Very reliable I understand and well liked by pilots that flew aircraft with that engine. I might have a picture of it somewhere.

Thread: Collet Chucks out of true
04/08/2019 14:50:03

Hi Guys,

The biggest problem with Chinese ER collets is that they are not properly cleaned and deburred. I've found that there are often tiny burrs left after they have been slit. In some cases large slivers of metal have been left.

I use a Stanley knife blade to clean mine and remove the swarf that has been left. After cleaning properly all the ones that I have used have been in spec. I posted pictures on another forum of the worse ones I had.

Stoning the burrs off is easy on the larger collects, not so on the small ones.

Thread: WM18 - Z Axis power feed
23/07/2019 20:13:36

Sorry Guys, I'm getting confused, I was thinking table feed.

But a wiper motor would still do the job of moving the head up and down.

23/07/2019 17:29:51

Anything wrong with pressing a window screen wiper motor into service ? A 3 to 12 volt psu will allow variable speed.

I have a tumbler reverse on mine which gives me a centre off position and allows the handle on the other end to be used.

Thread: Countersink choices
30/01/2019 11:17:30
Posted by pgk pgk on 30/01/2019 10:39:22:
Posted by Douglas Johnston on 30/01/2019 09:53:02:

I find the Weldon style zero flute type tend to be more forgiving than other types and cut very cleanly when sharp. Not so easy to sharpen though where the cutting face is formed by an angled hole through the cone shape.


I've not had need to sharpen mine yet but always planned to spin it up in a cordless drill and offer it up against the belt sander?



Don't do that, you will quickly ruin it !

Weldon single hole countersinks have a tapered cone ! You can see it if you use a pointer aligned with the edge of the cone and rotate the countersink. There is about 20 thou of taper on them.



Edited By John Baron on 30/01/2019 11:18:07

Thread: Hemingway Knurling Tool
09/12/2018 12:17:07

Hi Mark,

I would have glued both pieces together and put them in the four jaw on the lathe, drilled to remove the waste and then bored both holes to size.

However its an interesting technique that you have used. I'm watching with interest.

Thread: Flycutters: help to understand 3 different types
09/12/2018 12:07:32

Hi BW,

Very good effort !

First thing I noticed from your first picture, you have far too much tool stick out. Rigidity is the thing here. I also notice that you have the spindle secured with two nuts. Whilst its hard to see on the picture of mine there is no spindle below the bottom of the disc. The spindle on mine was pressed into a bored hole, and I also used superglue to make sure that it did not move. Whilst not absolutely required, I also faced off the underside whilst holding the spindle in the lathe chuck.

I did a lot of playing about with tool bit shapes. The rounded edge seen protruding through the disc is the one that I use for alloys. There is only about five or six degrees of rake and the front face is virtually flat.

The toolbit for cutting steel is quite hooked. I basically copied my lathe tools.

Last thing ! Check your mill tram. Under ideal conditions you don't want the cutter taking more off on one side, this is most noticeable on a long cut when cutting in one direction and the cutter is taking a shave off at the other side.

07/12/2018 19:30:48
Posted by not done it yet on 07/12/2018 12:57:13:
Posted by John Baron on 07/12/2018 12:09:38:

... The really hard part was making sure that both the male and female parts fitted together properly. ....

Well done, but isn’t that what Gib keys were invented for? One side could be made as a straight edge if the key was retained in the other plane. An infinite number of attempts could then be made to make the key at just the right shape.smiley

I agree ! But at the time I had only recently got the mill, so it was very much an exercise to see if I could make one. I've had a Myford S7 for a long time, so making a suitable fly cutter was the easy part.

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