Member postings for old mart

The thick cutter shown is intended for use on a horizontal mill, not an R8 arbor which is for slitting saws. Slitting saws are best used without a key, so they slip if jammed. The forces through the thick cutters are much higher and they are used with keys and spacers on horizontal mills.

Edited By old mart on 27/08/2023 17:29:25

When I looked at one of my depth mics, I realised that the lock mechanism holds the depth rod, and has nothing to do with the micrometer thread 10. The collar 3 should be tightened back up in stages with the micrometer thread 10 screwed in halfway, tighten until resistance is felt and then back it off slightly until the thread feels smooth throughout its travel. With the nut 7 removed from 10, find the shortest rod and put it in place within 10 and stand the mic base on a flat surface. Then unscrew the thread 10 until it just touches the head of the rod. You then remove the rod and fit the barrel 11 with the zero in line with the inner scale. Take care not to turn 10 as you fit 11. Hold the parts together tightly on the taper as you fit nut 7. Then assemble with the shortest rod and screw on 6 finger tight. Check how close you are to zero using the flat surface. If you are close, a fine adjustment to the inner barrel 9 can be made by turning it, or if the zero is too far, then unscrew 7, break the taper and try zeroing again. This requires some patience, and luck. Hopefully, the rods will still be set, they are difficult to calibrate.

Before reassembly, you should use a spray degreaser (not water based) and lubricate the threads with light oil.

It would make good bushes like bronze or brass.

I have two e-stops on the Tom Senior, both latching and turn them both off to make it harder for unauthorised people monkeying with it. There is a window in the metal box that the VFD is housed in and NST (no start) shows when the e-stops are active and RDY (ready) when the green button can work.

The screw 10 should unscrew from the base of the mic, (RH thread). The lock might be jammed and should be backed off or maybe totally removed first, the 4.1 to 4 series of parts. If you still cannot unscrew 10, then you will have no option but to unscrew 3 about 1/2 a turn, as that would also clamp 10 and make it hard to turn. Have you got the spanners that are made for this mic?

Edited By old mart on 25/08/2023 21:17:32

I chose a 6 pole 1hp motor for the Tom Senior light vertical R8 conversion, it can reach 2000rpm, but has been programmed to no more than 1500rpm, which gives a maximum spindle speed of about 3000rpm, which seems a sensible maximum. The benifit of 6 poles is that it looses less torque at lower rpm which with the pulley combinations gives a really good range. I bought from the inverter supermarket and would do so again.

I have a tin full of special taps at the museum, kept hidden lest somebody mistakenly use one. They have accumulated from tool boxes donated over the years. Every one a special, designed to do a single thing better than an off the shelf size, and much too pretty to chuck in the bin.

The code on the ISO or BT40 collet body would tell what the collets are, maybe googling it would help. Whatever they are, it would be a waste of time trying to get them usable on R8.

Do not try to move nut 3, it is for adjusting the fit of the micrometer threads as you screw them in and out. Your their photo shows the knurled parts 6 and 11 which should be unscrewed (RH thread) and screwed back together with one of the length rods between them, only finger tight. In your photos, the nearest part in the first photo looks like the micrometer leadscrew 10 and the nut 7 which have to be fitted into part 11. They can also be seen in the bottom of the fourth photo and at the left side of the fifth photo. The micrometer leadscrew minus the nut has a tapered part next to the nut thread and there is a corresponding taper inside the barrel, part 11. When the parts 10 and 11 are tgether the thread for the nut 7 should be visible. What ever you do, never hold the threads on part 10 with anything metallic, you will scrap the lot, use only plastic pads if you must grip them in pliers. Do not do up the nut 7 tight yet as adjustments will have to be made.

If you can get the mic back together, there will be some fine adjustments before it can be used, first things first, at this early stage.

We use guards at the museum for milling and turning and have a very good record regarding safety. The last accident was somebody falling off some staging and cracking a couple of ribs. We have the added responsibility to avoid adverse publicity by stupid actions in this enviroment.

 I am in the process of designing a chuck guard for the Atlas which is a bit of a challenge.

Edited By old mart on 20/08/2023 20:11:33

You will get more precision if you use a small fly press with tooling to fit it. The trouble with trying to get bends is the springback that varies with every metal alloy. The most stable results are to bend slightly past the design angle and then use minimum force to bring the bend back to optimum. I did a lot of straightening of part machined aircraft components part way through their manufacture and there was always some springback to take into account. I kept a book with the "recipies" for parts as once the first had been successfully finished, the others took 1/10 of the time and this also worked for future batches.

Careful Jason, there are people about who would take you seriously.

As the price of fixed steadies to fit the Smart & Brown model A at the museum was ridiculusly high, and we have milling capacity, I bought two cheap ones on ebay. One was C shaped and would manage about 50mm diameter and the other was a two part hinged one with about 75mm capacity. The bases were modified to bolt onto aluminium 40mm square barstock milled to fit the bed profile, so the centre point of each was on the spindle axis and each using a bolt through clamp. The large one had an extra set of fingers made by us with little ball races to complement the original bronze ones. The work very well and cost very little. I was extremely lucky with getting a travelling steady as an unidentified one came up cheap and turned out to be the exact one for the lathe.

Too late to make a difference, but for a small tabletop wood lathe, the axial forces would be well within the capacity of these blocks. The Lidl lathe will be a fine start and ready to use immediately, assuming some tools and wood are available now, good luck.

Pratt Burnerd and Bison adjustable chucks cost as much as many people spend on their lathe.

I would agree with DMB using a similar method used on circular saws which also have staggered alternate teeth. The simplest way would be to sharped-n the alternate teeth and then turn the cutter around on the spindle before re-aligning and cutting the other teeth. A proper tool sharpener probably simply changes its angle before lining up with the second set of teeth.

Having the motor speed control with a VFD complements the original series of belt speeds, or gear ratios and should not be an excuse not bother to use the mechanical gearing. When I bought a VFD and a new motor for the Tom Senior mill, the benifits of the original 4 belt speeds were not forgotten and the motor chosen was a 6 pole 1hp one. This runs about 900rpm at 50Hz so the Schneider VFD was programmed from 25 to 75 Hz which retains a good proportion of the power even at the lower speed provided the mechanical speeds are also used. Some people will try and get a motor to run at ridiculowsly low frequencies where the torque is very limited rather than bother to gear down.

I fancied one of those 350's.

I replaced the gently sloping roof of my garages, total 22 x 17 feet asbestos with the cheapest possible roof. Single layer industrial building roofing with two strips of fibreglass, one for each adjacent garage. The consensation was bad until I bought sheets of expanded polystyrene to fit between the joists next to the underside of the roof. There was still some condensation from the translucent fibreglass panels, but 95% had stopped. The modern roofing of this type is usually double skinned with about 75mm of expanded polyurethane and the translucent panels are also double skinned. Cutting and fitting expanded polystyrene, if it is still available, inside the building, even 12 mm thick will provide very good insulation.

I have never seen a train 7 metres long in OO gauge, it sounds like Australian or from the USA.