Member postings for Alan Jackson

Well done Tony, It really looks the business, Looks more purposeful than the original must have looked. Such a shame you cannot ride it.

Alan

I use this triangular toolpost, which can be also used by mounting the circular spacer block beneath the triangular toolholder and the spindle run in reverse (if it is safe for your lathe to cut this way) I think it gets a slightly better finish this way.

Alan

Edited By Alan Jackson on 17/06/2023 17:48:23

Edited By Alan Jackson on 17/06/2023 17:49:07

I have a Colchester Chipmaster and I have added tee slots to the cross slide. This with a few attachments gives it all the versaltity that a Myford has and much more.

Alan

Hi Taf,

Thank you for recording your struggle to get this mill as good as it will be when finished, Very interesting to see your solutions to the problems. Its going to be a great machine when finished

Alan

In MEW300 I proposed a small adaptable lathe that could be easily changed in stages from a simple basic lathe through to a version with powered axes then finally onto a fully CNC lathe that could also be used manually or a mix of manual/ CNC as desired. The version show has a cast iron bed but this could be simplified with rectangular steel bars. I attach a screenshot. There are many more screenshots in my album.

Alan

I my view the prismatic vee guide has the advantage of being a narrow guide that is automatically self adjusting for wear.

Whereas a flat bed has a wider guide and has to have means for adjustment to the guideway.

It also suffers in that the ratio of the guide way length versus width for a flat bed cannot match the ratio of a vee guide for the same saddle width.

Alan

You could do it this way and used an eccentric to engage or disengage the stepper motor from the feedscrew. It will also enable about a 10:1 reduction gear ratio. My one is geared down 10:1

Alan

With apologies for being flippant I wrote this some time ago

Alan

A while ago I tried out a vertical parting tool it worked ok but I must admit I did not give it exhaustive testing to destruction etc.

In order to clarify the operation of a vertical parting tool here is my rather primitive description of how I think it works.

Imagine that you are the parting tool holder whereby your two hands are held straight out from you body. You hands are gripped together and your fists are the cutting edge. You have a friend who represents the metal being cut and he (If you are a front parting tool) pushes down on your hands while you do you best to resist him pushing down. You can see that he can quite easily push your arms down. If you want to now become a rear parting tool you can turn round 180 degrees and your friend would now push your hands upwards still he can easily overcome your resistance to him pushing up. So in order to stiffen you up, say you are frozen solid or have rigor mortise and are wearing a large pair of lead diving boots to anchor you down. When your friend (or should I now say de-parting undertaker) pushes down on you hands he will not be able to move your arms down because they are rigidly fixed to your body and he have to apply more force until you tip forward on you toes. Note that as you tip forward you rotate about your toes moving your cutting tool hands deeper into the metal being cut. If you are now rotated 180 degrees to become a rear parting tool your friend (some friend) now has to apply more upward force until you tip backwards on your heels. Also note that your cutting tool hands now move away from the metal being cut as you rotate backwards on your heels. Now you have to play the part of a vertical parting tool as I am proposing, so you now can be thawed out or de- rigor mortised. So lay flat on your back and push one arm vertically upwards and clench your fist to form the cutting tool. Your friend now has to apply considerably more force to overcome your vertical arm. Your arm will be in direct compression and until your elbow or wrist give way you will have much less a problem resisting his downward cutting force. It will also not matter if you are a front or rear vertical parting tool as long as the rotating force is pushing down on your hands. You can now get up and go back to your work or whatever you were doing. I apologise for being so flippant but I hope it does explain the reasoning.

Regards

Alan

Cancelled

Edited By Alan Jackson on 19/01/2023 10:35:00

Hi all,

Does anyone know when the results of the 2022 John Stevenson Tropy will be announced, or have I missed its announcement?

Alan

I have found that if I have say a machining or construction problem, it is better to leave it for a few days, and I nearly always come up with an entirely different and better way to the first plan.

Alan

Edited By Alan Jackson on 08/01/2023 10:49:27

Edited By Alan Jackson on 07/01/2023 18:03:46

HI Noel,

A while ago I slightly remodeled the design in Solidworks. The fixed horizontal pivot is now a solid bar and the fine adjustment is now on the centre of the vertical arm assembly. I have shown the two separate components parts duplicated. Hope this explains things. The submission for the trophy only allows about four or five photos and a limited text so that limits an extensive description.

Edited By Alan Jackson on 07/01/2023 17:39:32

Hi Noel,

I have just found your comments on my grinding wheel dresser, and I apologise for such a late reply.

As to explaining how it works. It is just a fixed horizontal pivot rod mounted above the grinding wheel. The pivot rod is hollow and has a threaded adjustment screw protuding at the furthest end from the grinding wheel.This is to allow fine adjustment of the vertical arm assembly depth engagement with the grinding wheel. The vertical arm assembly is free to rotate on the horizontal pivot rod and enable the diamond to engage with the grinding wheel, the depth of engagement is set by the adjustment screw. The vertical arm assembly can be removed or slid away from the grinding wheel when starting the grinder and slid forward then rotated on the horizontal pivot to be swung across the grinding wheel face to dress the wheel. After dressing, the vertical arm assembly is withdrawn on the horizontal pivot rod and the grinding wheel is switched off for inspection.

I hope this clarifies the operation

Alan

Edited By Alan Jackson on 07/01/2023 11:40:44

This will do all you require

http://www.lathes.co.uk/stepperhead/

Alan

Edited By Alan Jackson on 07/12/2022 10:09:36

How about doing this, it can be mounted on the front side if the chuck is screwed on or the rear side if the chuck has a bolted or camlock mounting.

https://www.youtube.com/watch?v=S8HvS13L7MU

Alan

Superb

One of the reasons for designing and building the Stepperhead lathe was to try to show how outdated the Myford style lathes are. They were designed on the 1940s with a slow speed, plain bearing, headstock needing constant oiling. A separate countershaft arrangement is needed to vary the spindle speed by changing belts over differing pulley sizes and by engaging a back gear. Its sole saviour it that it has a Tee slotted cross slide, enabling various attachments to be fitted. The topslide design is a source of problems, needing a large weakening hole in the crosslide to locate and secure the topslide with awkwardly accessed screw fixings.

With Stepperhead the intention was to bring the homeworkshop lathe up to speed by a series of modular components that could enable the machine to change from being a basic simple lathe, then by adding separate packages i.e. stepper motors to drive the axes via a simple stepper drive circuit and finally by adding a laptop computer to CNC operation with an infinite range of threads and feed speeds in metric or imperial enabling the ability to perform many other operations. The spindle speed is inverter controlled from 15 to 3000 rpm. Backgear is enabled by a simple polyvee belt change. The ability to raise and lower the head and tailstock relative to the bed provided a massive range of operations, plus the ability to index the spindle as well as move the X and Y axes together or independantly enables infinite operation either manually or by CNC control.

The savings gained by eliminating the following items:- a separate countershaft, a back gear arrangement, a speed feed/thread gearbox, a tumbler reverse, and a spindle clutch, would have easily paid for the computer, stepper drives and motors and provided a quiet versatile machine.

Alan

Edited By Alan Jackson on 29/06/2022 10:14:12

Hi Hopper and vga,

Yes I do have a vertical slide for this cross slide. I could have carried out this operation on my Stepperhead lathe but the Chipmaster is a much bigger and more rigid lathe and even on this I could only make about .020" cuts without chattering etc. I modified the original cross sliide by adding 0.500" steel strips bolted from underside.

Edited By Alan Jackson on 17/06/2022 10:26:01

I have added tee slots to my Chipmaster cross slide this enables many operations like this

https://www.youtube.com/watch?v=YjjuNBnu_N0

Alan

Edited By Alan Jackson on 16/06/2022 12:01:34