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Member postings for Martin Connelly

Here is a list of all the postings Martin Connelly has made in our forums. Click on a thread name to jump to the thread.

Thread: Warco WM250V Screwcutting
02/03/2022 00:47:45

You need a gear with 40 teeth on the TDI. This will allow you to go 2mm x 20 = 40mm per half revolution which is 32 pitches of your thread. This is why metric TDI systems come with multiple gears for the TDI.

You could also go 1/4 turn of the TDI for 16 pitches (20mm) with this 40 tooth gear.

To use the 48 tooth gear on the TDI you would have to move 5 of your 12 divisions or multiples of 5 such as 10 or 15 which would move you in 20mm steps (16 pitches of 1.25mm). This is likely to be error prone which is why the 40 tooth gear is the best option.

Martin C

01/03/2022 08:17:11

To add to what DC31k has asked, how far do you have to move the saddle to rotate the thread dial one or five revolutions? Five is better for accuracy. A typical inch based one will move an exact number of inches per revolution, I would expect 2" but a metric one will move a multiple of a metric pitch so 50mm is a possibility. Doing 5 revolutions will help differentiate between the two.

Martin C

Edited By Martin Connelly on 01/03/2022 08:17:34

Thread: I need to screw cut a 19 TPI thread.?
27/02/2022 18:36:58

Some Smart and Brown lathes use a 95 (5 x 19) tooth gear for 19TPI. In this case you would probably look at 20tpi and replace an idler with a 95/100 or a 38/40 combination if there is an idler in the gear train.

Martin C

Edited By Martin Connelly on 27/02/2022 18:39:52

Thread: Clarkson auto lock
27/02/2022 12:52:04

Babiels, I have a 1/2 inch collet and sleeve that are of no use to me. If you want them you can have them for the price of the post and packing. Message me.

Sleeve is 0.811" bore, 1" outside diameter 30mm long

Martin C

Thread: Mechanism with spiral spring
26/02/2022 08:08:33

Two tone door bells do this.

Martin C

Thread: Sieg C1 lathe autofeed and screw cutting
25/02/2022 08:20:58

sieg change gears.jpg

The illustration from the manual shows the gear train set up for fine feed of 0.05 mm/rev. There is a means of adjusting the position of Z1 and Z2 to obtain the correct gear meshing, item 79 support plate, usually referred to as a banjo due to its shape on a lot of lathes.

Martin C

Thread: How to remove a SMD resistor
24/02/2022 17:38:48

The controls department where I used to work used a hot air tool specifically designed for this type of thing. Looks more like a soldering iron than a hairdryer.

Martin C

Thread: Gear hobbing
24/02/2022 17:36:29

Big difference between a mandrill and a mandrel devil

Martin C

Thread: Tube Benders
22/02/2022 18:00:53

I have seen one that says 24.3mm radius, however this is not defined as inside, outside or centre line. My bet would be centre line radius as it is about 2.5 x diameter, 3 x diameter and 4 x diameter for the 3 sizes it bends. 2.5 diameter is about the tightest you can go with simple tooling that presses the pipe around a former without getting too much ovality or other issues with the bend.

Martin C

Thread: What are the yellow fittings please
21/02/2022 08:54:17

Merseyrail use the third rail outside of the running rail system.

orrell park station.jpg

Martin C

Thread: Acceptable run-out on Axminster SX1 milling machine?
21/02/2022 08:39:10

You said you gently snugged up the drawbar, which is all that should be done to it. What you have not mentioned is how much effort you put into tightening the collet nut onto the collet holder. These need a lot of torque to seat them. It will not change the internal runout of the holder though.

A further check that should be done is to mark the collet holder high point with a pen then remove it, replace it in a different position (eg 180° about) and repeat the exercise to see if the high point stays at the same place on the holder or is now in a different place. There is a possibility that the spindle taper is only correct at one point or that there is internal damage or debris stuck in it.

Martin C

Thread: Front door locks
19/02/2022 18:07:12

The Euro cylinder deadbolts in the link do not have a British Standard Kite Mark on the face. There is no information as to them being bump, pick, drill or snap resistant. I would look for something that at least had these features and was prepared to state that to be the case.

Martin C

Thread: HOW FAST - ANEMOMETER CALIBRATION ?
18/02/2022 11:51:03

Hold it out of a car window on a calm day. Use the speedo to calibrate it. Account for the fact that most cars have a speedo that under-reads by a couple of percent.

Martin C

Thread: Tufnol or Acetal for hollow bolt
18/02/2022 09:38:57

Tufnol comes in different types to suit different conditions. Is there any obvious thread (as in cotton thread or similar) in the ones that have failed? If so which way is it laid? Is there any sign of it being layered like a piece of slate? This may give some indication as to the best material. I would be inclined to stick to what the original design used to cater for temperature, pressure and contaminants.

Martin C

Thread: TREND VARIJIG Part Dimensions Wanted?
18/02/2022 09:27:59

I think it will be the same thickness as the frame plus the thickness of the part of the template guide that rests on top of the frame.

Martin C

Thread: 5-40 machine screw
18/02/2022 09:23:35

This is where some of us reach for our Zeus Books as discussed in a recent thread.

Martin C

Thread: dovetail cutters infeed per cut
18/02/2022 09:19:24

The largest diameter on the tool that will come into contact with the workpiece is what you should use as a guide for rpm. So in your case start by treating it as a Ø1" cutter or a Ø1" drill. Then as stated above feed at a speed and depth of cut that cuts without rubbing or labouring the machine.

If you have a low power machine you can do the height in two parts, cut the top half a little less than final dimension. Remember this will not be the same point as the final dimension with the tool down to the bottom of the dovetail. Then do the bottom half taking the last few passes to final dimension over the whole of the machined face.

Another option for a low power machine if you have a suitable cutter is to take out the bulk of the material with a woodruff or tee slot cutter, saving the dovetail cutter for the remaining material.

Martin C

Thread: Here's an interesting one
17/02/2022 15:32:15

There is something I would label a scam on eBay, the listing of a photo or box with the detail that what you are buying is a photo or a box not being in the main description, only lower down in the details. I am sure it is designed to catch out the unwary looking for a bargain. Clearly if you read the full details you will not part with your money but I bet there are some who will get caught out and keep quiet due to embarrassment.

Martin C

Thread: Covid
15/02/2022 14:25:30

A report out today links low vitamin D levels to higher likelihood of catching Covid and having a severe case compared to those with a good level of Vitamin D. It would be nice to be able to step out into the sunshine to improve my levels but it has just been cloudy weather (not climate) today.

Martin C

Thread: Learn to use a metal lathe
15/02/2022 13:25:28

Blondihacks on YouTube is probably a good place to start as she covers some of the beginner's questions in a good, clear way.

Metal Lathe Tutorial 1

Absolute Beginners Start Here

Absolute Beginners - Day 2

Martin C

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