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.|
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...|
A quick tip ! To magnetise a screwdriver, just drag it over a magnet a few times.
Does not work for stainless items.
A cheap source of 2.5, 3.0 and 3.5 mm coarse torx screws are old hard drives !
|Thread: Threaded Norman Toolpost|
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.
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?|
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|
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
Did you bother to actually read my first post ?
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
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.
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|
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|
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|
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|
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.
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|
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|
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|
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.
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.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.