Member postings for old mart

I would look into replacing the belt with a linked belt.

Ebay UK 254121291285. This type comes in several sizes.

Edited By old mart on 09/08/2019 14:20:34

I hope the feared storms do not materialise, having seen the pictures of the water cascading over that relief weir before the end part failed. That amount of water flow would undoubtedly overwhelm the small channel which runs alongside the north side of the dam. Having reduced the water level has hopefully bought enough time for any flash floods to stop before another overtopping.

I just made a height gauge that matches the top of the tool tip which is just the right height to face off perfectly.

I know nothing about clocks, but those marks are familiar, spooky, isn't it.

The six splined shaft fitting should be a clue. A measure of the bore as well as the diameters/teeth count and gear thickness should do it.

The Smart & Brown model A that I use has only got 25mm through the spindle, a nuisance at times.

Posilock and autolock and Acramill are different systems utilising threaded shank milling cutters.

Posilock is used by Osborn in their Titanic II system.

Autolock is used by Clarkson.

Acramill is another system using the same threaded cutters.

Chronos LTD sell new posilock chucks and spare collets. Their collets will fit Osborn Titanic II also, but not Clarkson or Acramill.

If you google Clarkson Autolock instructions, there are diagrams showing how to use them which also apply to the similar posilock system.

I did some machining on the outrigger bearing holder for the bottom of the quill. It is screwed into the quill body by a 26 W X 2.048" thread, just right for 2" OD taper rollers to fit in the 2" bore. There is a 2" long spigot which just fits the quill bore and a shoulder, which , with the thread and the bore for the spindle, were all turned in one chucking. Trouble started when I turned the work round to finish the external part and the bottom bearing housing. I couldn't quite get everything running exactly within 0.001" tir, even with my best four jaw chuck. Tomorrow I will bore some soft jaws in the Pratt 6 3/4" serrated jaw chuck. Now I am glad that I decided to have a 1.999" by 2" long spigot in the design, plenty to hold in soft jaws, and room to check the shoulder and skim if necessary. Then I will feel confident in getting the concentricity I want.

I have finished the machining of the lower part of the R8 spindle. As the upper half will now be part of the existing spindle, I shortened the lower part, bored it larger, about 20mm diameter and threaded the outer 3/8" long. I used a lefthand threading bar cutting away from the chuck. As the available grooving tools would not quite go down the bore, I used the 16er laydown insert to create a start clearance at the bottom of the thread. There was a quiet ting of the tip fracturing, I had forgotten to put the spindle in reverse. I got the insert turned round and the spindle going the right way and the thread is fine.

If there is increased rainfall in the area, it will go downstream whether or not the dam exists. Normally the dam would be full and overflowing. They may have to stop pumping if the rain starts in earnest, but there will now be a period of respite before the level rises back to danger levels. That bypass channel on the north side of the dam is of vital importance now.

That EML290 looks good, I see that a DRO is optional, which may well be within your budget.

I noticed in the Wikipedia entry for the dam that a proportion of the water feeding the dam is diverted into the stream alongside. I assume that steps have been taken to divert all the incoming water into the stream and that it can handle the increase.

I recommend getting an indexable milling cutter such as this 16mm diameter type advertised on ebay UK 401828258237. It takes APMT11 and APGT11 size inserts. There are alternative sizes such as these 12mm diameter ones 123850739467 which include inserts for steel. APGT11 inserts for aluminium 273401110660. If the holders are too long, just cut them down with a hacksaw.

I last set the OD of the Pratt chucks to run dead on was when I gave the inside of the jaws a light grind to remove the slight bellmouthing. I used a solid carbide drill to provide tensioning holes through the case hardened jaws. The Pratt chucks have good tight scrolls accurately ground and centre within 0.003" at all diameters. I rarely need to fine adjust the chucks, but the option is always there.

Edited By old mart on 06/08/2019 16:45:24

I see the HV has iso30 spindles which is a step up from R8, and tooling is quite easy to obtain.

At your budget, you have a very good choice of machines from Warco, Axminster and Chester, to name three off the top of my head.

Glad you remembered, I have only got experience of the light vertical which lacks the power feed. You will find that the main column is the heaviest part. The base is a weldment and much lighter than it looks.

Good luck with the move.

Those people who are worried about the possibility of the chuck moving when only the bolts are holding it to the backplate are rarely concerned when using a milling machine with no register at all and 100% interrupted cuts.

I have four chucks, two 5" Pratt Burnerd and a good Chinese 125mm and a reasonable Chinese 160mm modified to enable fine adjustment. The Pratts, unusually, have front and rear mounting holes/ threads in them, so I use six SHCS screws in them. The 125mm is rear mounting, originally three bolts, but there is plenty of space to drill and tap a second set. The 160mm has six 6mm SHCS screw in the rear because the backplate was slightly under 160mm and the original 8mm's would have been too close to the edge.

The registers in each backplate are about 0.010" undersize and the bolt holes are loose to match. Just slackening the screws a little enables the workpiece in the jaws to be set dead on with a DTI, by gently tapping the body of the chuck with a copper hammer and rechecked when the screws are retightened.

The chuck manufacturers would not recommend this as they want to sell set tru types at double the price.

Of course this only applies to scroll chucks, not four jaw independents.

Edited By old mart on 05/08/2019 16:50:07

There is always a danger of sucking up unexploded munitions from various wars off the British coasts.

I second Howard Lewis's approach. You need to know what interference fit the new ring gear will need and how wide it is, as a shoulder is required on the flywheel. Try a file on the teeth, if they are not too hard, then your lathe should cut them off with no problem, using carbide inserts such as TNMG. Remember to set up the flywheel the right way round for the shoulder.

It depends whether you are a beginner or not.