Member postings for Peter Cook 6

Another thing yo think about is the ratio of milling to drilling you will be doing. With single size collet holders, each time you want to drill, you will need to swap the holder for the Jacobs chuck. With ER collets you can pick the size and hold drills as well as the milling cutters. I have a much smaller mill, and ER16 collets. I rarely swap out the holder for the Jacobs chuck.

Can't speak for a long case, but I have a Vienna wall clock with repeat. The repeat cord comes out through the side of the case, which makes sense as you would not want to open the case to activate the repeat (It would probably be dark).

The "cord" on mine is heavy sewing thread 0.9mm dia. it is threaded through the lever and has a knot tied to stop it pulling through

0.85mm thread has a break strength of 85lbs. If the repeat takes that much load you have other problems with the movement!

Edited By Peter Cook 6 on 26/02/2021 21:07:39

Put a nut on each bolt and tighten down to lock the bolts into the holes . The thread shape will tend to centre the bolts. I measure the outside distance and the diameters of the bolts to do the math. I find inside measurements harder to get accurate.

There is some useful information at

Understanding Microscopes and Objectives | Edmund Optics

It implies that the distance from the object to the real image plane of the microscope is very standardised. May not be true of prewar Russian units, but looking at your two samples I would suggest that they are designed (optically) to be very similar. The only difference being the mechanical design of the focus mechanism.

I suspect that you will end up repositioning the thread in order to get the objective to focus.

Edited By Peter Cook 6 on 20/02/2021 14:22:44

Assuming the top is the English one, and the other the Russian, are the focal planes the same? The threads seem to be in different positions along the tube as well as being of different pitch, or is there something I am missing?

As it stands, can't you simply machine off the Russian thread and cut a new English thread in the correct place for the English microscope, which seems to correspond to some solid material on the Russian tube.

Try the free versions of some of the software. See what suits you. Like you I have no design background. There seem to (me to) be two paradigms which underlie the software. One is based on orthogonal projections which are combined to create 3D models. The other starts from 3D and offers differing views.

My brain struggles to integrate orthogonal views, so I found the first style of software hard to get to grips with. I tend to think in pictures so the second type seemed to suit me better.

I settled on MoI as I found it the most intuitive (to me), but even so the learning curve was VERY steep. MoI is not free (far from it) but as I have got to grips with it I have found it easier and easier to create models - and it links (via Cura) with my 3D printer to make the things I visualise.

Thanks for the encouragement.

The lathe (a 6mm Wolf-Jahn copy) is really only used for polishing pivots so the loads should be small. If I do have problems I will try PETG.

An update for anyone interested. I modelled the pulley set, and printed it in PLA in two pieces. A single motor pulley and a set of three to drive the lathe. The largest pulley in the set of three is 55mm diameter. I printed with standard Cura settings for my Ender 3Pro, no support and standard 20% infil.

It came out well. With 16 x 8 x 5 bearings presses into recesses in both ends of the 3 pulley stack, a piece of 8mm steel rod for the spindle, and M3 bolts to hold it together. Very pleased so far. Todays project is the frame for the motor and to hold this set.

12.7 per inch is 2mm pitch ( exactly). The manual seems correct.

Thin stainless sheet glued down on a piece of MDF. Thin stainless is available as cooker splashbacks or just as sheet.

I am planning (what I do to add to my project list when it's too cold to go across to the workshop) to make a back shaft setup for a 6mm Wolf Jahn lathe which is mainly used for polishing clock pivots.

The lathe has a three step pulley in the headstock and uses 3mm belt. It's driven rather too fast by a small sewing machine motor (which came with it).

After 3D drawing a suitable set of pulleys for the back shaft setup, it occurred to me that rather than turning them out of aluminum, It might be equally possible to 3D print them. The OD of the largest pulley is <50mm and the overall width of the set is <25mm. They will ride on some 8 x 16 x 5 bearings I have left over from another project.

Has anyone printed pulleys in this way, and used them with 3mm round belts.

Any gotcha's or specific materials to use.

Just a gentle warning. Six months after getting whichever lathe you choose, you will discover a desperate need for a mill.

Thanks, the clamping option looks a good one. Not sure the level of precision I can achieve is quite up to Tug's suggestion - although with three to make I might try it.

Thanks again.

Edited By Peter Cook 6 on 05/02/2021 19:19:23

I want/need to make a block with a split collet to connect a drive rod to a leadscrew.

The suggested method when making the collet is to use a through hole and leave a flange on the back which can be used to clamp the collet blank firmly in place while drilling the hole for the shaft.

Because of the shape of the block with the leadscrew thread at the back I can't do that. The collet body will be 10mm brass, the block aluminium. The shaft is 8mm diameter

I was thinking of supergluing the drilled and tapped collet blank into its hole, drilling the shaft hole and then using heat to get the shaped collet out for finishing.

Will superglue be strong enough to hold the blank in place while I drill the 8mm hole? Will heat be enough to get it out? Or are there better ways of doing this?

Edited By Peter Cook 6 on 05/02/2021 18:09:58

More likely to be the (un?)intended consequence of a hub and spoke distribution network. From wherever it started to the sorting hub, from there to the local distribution depot, thence to you.

Thanks for the kind comments.

John H - Quite correct it was a 1/4HP induction motor not a synchronous one. My excuse is that it was late when I typed the posting.

Hollowpoint - I have not really used it in anger yet so can't really comment. However tests show good torque down to 400rpm on the motor (more than the induction motor) and adequate down to 200. That gives me 135rpm (400) and <68 (200). I can control the motor down to about 70rpm (26 rpm on the spindle), but there is no useable torque down there. Top speed is limited by the spindle bearings which are rated for 10,000 rpm.

Ian T - that looks exactly like the kit I got (down to the same remote control), however I decided against using the DC control board, display and remote as you did. Investigation of the motor power control (the black box) showed that the input from the control panel to the board was a simple 5v PWM signal and the 5v supply and input stage on the board within the power controller was fully isolated from the power side.

I decided to build an Arduino based controller (another learning curve) which would also measure and display the spindle speed. The display is a standard 4 * 20 character LCD display. Like you I designed (in my case using MOI) and printed a box for the Arduino, the interface circuitry and the display (two more steep learning curves - the box was my first attempt at 3D printing).

The speed measurement is by a Hall sensor (again standard Arduino kit) activated by a couple of small magnets let into the back of the spindle pulley. Another bit of 3D printing holds the sensor in place between the pulley and the back of the headstock. The control knob is a rotary encoder (I decided a simple pot was too coarse for the 0-4000 rpm of the motor). The run/stop switch and control knob are in a separate box so that I can move them about and find the best (most convenient) location before building them into the new baseboard.

In the longer run I plan to add feedback control to the spindle speed using the PID libraries available for the Arduino - but so far attempts to do so have ended in failure - I am going to have to get out my old control theory books to get the parameters right.

If anyone wants any more info, please let me know.

I enjoy seeing the projects other members have completed, and am in awe of the standard of engineering on show. As a contribution, and in thanks to those who have helped me up the learning curve I offer phase 1 of my first real project.

I have converted my Taig lathe from a basic synchronous motor to an Arduino controlled DC setup. Speeds now available range from <100rpm to 10,000 rpm ( spindle limits).

The new motor is a 200V DC 200W 4000rpm ex vibration plate spare from E-bay which came with a a driver unit (the black box) which accepted a PWM input.

Implementation has involved learning turning, milling, Arduino programming, 3D design, 3D printing, and resurrection of my 50 year old electronics expertise.

Phase 2 is to build a new baseboard to bury the wiring, Phase 3 is a leadscrew and thread follower system for screw cutting.

More images are in the Album.

Edited By Peter Cook 6 on 02/02/2021 23:36:30

Most of the dial gauges I have (albeit not in Mitutoyo's league) came with both a lug back, or a flat one, and can be interchanged. All with four screws.

If you don't have a flat back in the original packaging with yours, I suspect it is fairly simple to make one. Mine are simple flat pieces (of steel or plastic depending on the guage quality) a couple of mm thick with four mounting holes round the periphery.

Take the lug back off (in a CLEAN environment), measure it up and make one.

I think it depends on the magnification you are looking for. I have a set of these. https://www.amazon.co.uk/gp/product/B06XYYCFRP

They work OK for High magnification work, but you don't get binocular vision. The focal distance is too short for both eyes to see the object.

For binocular vision I use a pair of strong reading glasses (x3.5), with a flip up set of magnifying readers clipped on top (https://www.amazon.co.uk/Reading-Glasses-Magnifying-Magnifiers-Readers/dp/B07WW3J4ZN).

The readers are stronger than my reading prescription, and give nice magnification about 12-24" away. I can see things on the bench 3-4ft away, but looking for stuff across the workshop means swapping to my regular glasses. With the extra lenses flipped down (mine are x2.5) vision is highly magnified at 4-8" but beyond about foot all is a blur.

I find the combination great. Flip down to see when the cutter just touches the work, flip up to watch the machining.

I suspect the reason your friends are so expensive is that they give High magnification at long working distances - and that needs specialised optics.

Edited By Peter Cook 6 on 14/01/2021 21:45:11

That is the beat adjustment. The pin at the other end of the arbor is apparently lined up with a window before starting, and the escapement should then be in beat.

There is a thread on the NAWCC bulletin board that discusses this movement.

Gustav Becker Verge Crutch Assembly | NAWCC Forums

It shouldn't need an lot of friction, the force it's transmitting is only the drive from the escapement to keep the pendulum ticking. If it is slipping out of beat when running, try cleaning and roughening the two mating surfaces (slightly) to increase the stiction between them - and don't oil them!!

Edit - Michael got there while I was typing!!

Edited By Peter Cook 6 on 14/01/2021 18:26:26