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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: Bandsaw woes
11/04/2017 15:22:46

I have had problems with the guide rollers being too tight for the blade thickness. Over time the blade was squeezed enough to thin and stretch the part that went through the rollers. The blade did not stay straight as a result and the weld snapped with very little wear on the teeth. I opened the gap slightly on the guide rollers and now the current blade has been in a long time with no sign of the distortion to the blade that was showing up before. Industrial bandsaws often have some sort of indicator to let you know when the blade is at the correct tension. I have seen pressure gauges on some and on others a Belville spring system with a coloured ring on part of the tensioning mechanism. When it was tight enough the coloured ring was in line with a pointer. It is surprising how much tension is put on some of these blades.

Clarke CBS7MB I got for half price because it had been dropped in its crate.

Martin C

Thread: Alternative to PC based Cnc controllers
11/04/2017 14:17:39

The problem with all this is - it makes me want to spend some money and play with one myself. I look forward to reading the complete tale when it is written up.

Martin C

PS Is play the correct word for this?

Edited By Martin Connelly on 11/04/2017 14:18:15

Thread: Work Holding: drilling and taping a ball bearing
11/04/2017 13:57:06

How much of the surface of the ball is actually used? I ask this because it looks to me like you could just turn a spherical surface on the end of the rod to achieve the same result. Use a suitably hardenable steel and polish afterwards.

Martin C

Thread: Drilling holes
10/04/2017 17:07:50

The problem of taking too large a bite with a big drill is that the feed per rev for the outside edge of the drill is too large for the edge near the centre. If you reduce the feed per rev to suit the inside diameter then the outside runs the risk of rubbing instead of cutting. So a technical reason for going up in stages that is not just to save overloading a small machine.

Martin C

Thread: Aircraft General Discussion
09/04/2017 10:29:06

How long was the flight time to get there? 45 minutes straight and level at top speed? Round here and Lincolnshire were mentioned. You could have said I thought Great Britain was flat.

Martin C.

09/04/2017 09:32:04

With the highest point in Lincolnshire being 551 feet above sea level Geoff's tale seems a bit less than verbatim reporting. You need to get to North Wales, the Lake District or Scotland to get any peaks near to or over 3000 feet high. Situated between Waddington and Scampton Lincoln's cathedral high up at the top of Lindum Hill was the biggest hazard but all crews took care to avoid.

Martin C.

Thread: Traction engine tyres
04/04/2017 18:09:48

You could buy rubber sheet of suitable thickness and cut slices off it. Don't know what you think is expensive.

Martin C.

Thread: Warco WM250
03/04/2017 18:09:03

Maybe the spade connected to the live lines fed a power on lamp.

Martin C.

Edited By Martin Connelly on 03/04/2017 18:09:23

Thread: Who supplies indexable tools for screwcutting.
03/04/2017 17:54:19

Buck and Hickman sell to industry, prices will surprise you though.

Martin C.

Thread: Run out on a rotary table
29/03/2017 18:36:46

Here is what I described a couple of posts back. Using a spin indexer for simple dividing with whole degree spacing. Clamping the end in a vee on a screw jack I set the depth of cut to 1mm as this would leave a small untouched surface opposite each face. This would take away variations due to burrs on the apex. The resulting dimensions from flat to apex varied from 11.02mm to 11.05mm.

img_20170329_181417.jpg

Martin C

Thread: Lifetime Guarantee ( Ford)
29/03/2017 14:50:36

In an effort to save fuel modern engines run leaner. This results in both higher exhaust temperature and less moisture in the exhaust gasses resulting in a rapid exhaust tube heating.. Without a carburetor, which never gave exactly the best fuel air mixture but was close to the best ratio over most of the engine range only, modern engines with sensors in the exhaust gasses make exhausts last longer. I think a lot of damage was done by mechanical chokes and short journeys where the exhaust was left with internal moisture in a cool steel tube.

Martin C.

Thread: New pound coin
29/03/2017 13:58:41

Due to the cost of changing the coin mechanisms for machines when a new coin is introduced I see new vending machines are being fitted with card readers and can accept payment by Android Pay and the Apple equivalent (not sure of the official title). We are heading towards the cashless society that the government would surely love as it will kill some of the cash transactions that avoid the taxman's eyes.

Martin C.

Thread: Lifetime Guarantee ( Ford)
29/03/2017 13:51:28

My first car was an old Hillman Minx (B reg 1964 I think) with very thick steel bodywork. Tried bashing out a dent and could not move it.

I've just replaced my 11 year old car, the gearbox was dying, the engine was starting to use oil, the CV joints were getting some play and the gaiters on them were starting to perish. Three of the alloy wheels were starting to weep air at the rims (one needed filling up more than weekly as it dropped from 35psi to 10psi in that time). It needed new pads at the back and the rear disks were looking a bit scored. The plastic covers over the lights were getting fogged by micro abrasions.

The bodywork was perfect.

Martin C.

Thread: Run out on a rotary table
29/03/2017 13:29:45

I know you have a rotary table and are using it for this task but it seems over the top for simply rotating something to 5 different positions. I would use my Stephenson's indexing head and ER32 collets (ARC Eurotrade sells them, they step in 1° intervals) for this type of job and as JasonB suggested support the workpiece near the working point with vee block, engineer's jacks, back plates or a suitable combination of them. Lightly clamped in a screw jack vee block would be my first choice. That way run out has no effect on the machined result.

You can use the same method with a rotary table just using it to rotate to the 5 positions and securing the work piece like you would for any other milling job to ensure a consistent result for each face.

Martin C

Thread: Making single-point Threading easier on a Mini-Lathe
29/03/2017 11:16:51

Regarding the rapid camera panning and splicing video segments together, would a split screen or an inset window be a good option. The software you used may have this as an option. It seems a good way of showing what a control panel is doing in other videos I have seen.

Martin C

Thread: Cost effective way for manufacturing a small plastic part
29/03/2017 10:55:55

You can get 4mm square nylon strimmer cord. It comes on a reel but a bit of warmth should allow it to be straightened out before use. Due to the problems of drilling plastics with accurate sized holes what are the material requirements you need to meet, something else may be a better option.

Martin C.

Thread: ER40 Collet run out.
29/03/2017 08:40:54

According to a blog in CNCCOOKBOOK the torque value for correctly tightening ER40 collet nuts is 140 ft lbs. The blog is quoting Tecknik USA.

**LINK**

Martin C

Thread: Machining Aluminium Bronze
22/03/2017 18:13:16

Due to its wear resistance this material is used for mandrels and wiper dies on pipe bending machines when bending stainless steel, it avoids cross contamination of the stainless with ordinary steels.

Martin C

Edited By Martin Connelly on 22/03/2017 18:13:45

Thread: drilling sandstone
21/03/2017 14:50:14

I would try a masonry bit. Why would you assume it is no good? You have not stated the diameter, that may have some bearing on the responses you get.

Martin C

Thread: Machinery removals
21/03/2017 13:25:05

David, the second slinging example is showing normal bending of the load under the forces caused by lifting but in an exaggerated way. It should show collared eyebolts but this may not show on a small graphic. It is a common and accepted lifting method as long as the "correct use of eyebolts rules" are followed. An understanding of the tension in the slings is important as well as the de-rating of eyebolts for an angled pull. It is necessary to understand the difference between working load limit (WLL) and safe working load (SWL) if you are to lift something in a safe manner. The department I work in regularly lift multi-million £ loads of 30 to 60 tonnes, we take lifting safety very seriously.

Martin C

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