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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: Hi from Mid Lincs
12/06/2019 20:19:55

My wife is from Helpringham.

Martin C

11/06/2019 17:57:00

Mid Lincs must be somewhere near Horncastle looking at Google Maps.

Martin C

Thread: Problem with slitting saw arrangement...
06/06/2019 18:23:54

It may help to increase the friction between the saw blade and mandrel by fitting a paper washer before putting the blade on. It will still slip if it jams but may have a little more friction than a metal to metal joint. If you have a second chuck maybe you can hold the mandrel body with it to tighten the drawbar before fitting the blade.

Martin C

Thread: Electronic Indexers - How Is Cumulative Error Avoided?
31/05/2019 14:14:31

I made a 127 tooth gear using the calculate each position method as 360 x X/127 and a stepper motor with a close coupled harmonic gearbox. It required 88.8888 steps per degree, just under 252 steps per tooth. I decided that was going to be accurate enough for my needs.

Martin C

Thread: What are these change gears for?
27/05/2019 19:18:22

It could also be used as an indexing plate for anyone who wants to cut 127 tooth gears to suit some other gear profile. Advertise it for this use as an option and you may get more interest in it.

Martin C

Thread: Harrison wiring
25/05/2019 07:37:04

A couple of things need to be known to help with answers.

Are there any covers or safety screens with switches that need to be in the safe position to enable operation?

Was it supplied by 3 phase mains at 415 line volts or a VFD at 240 line volts and what are you supplying to it?

Martin C

Thread: HSS or CS taps and dies
21/05/2019 20:21:59

I always use Rocol RTD, metric size minus pitch for drilling and anyrhing over 1.5 x diameter for thread depth is a waste of time.

Martin C

Thread: Work Holding For CNC Milling
14/05/2019 18:33:52

Connecting rod?

Martin C

Thread: Removing a sight glass
06/05/2019 20:38:36

Hoses Direct sell these as push in polyamide items for tanks with wall thickness of 5mm minimum. Diameter 24mm or 30mm. Really cheap so I don't imagine the Chinese lathe manufacturers would use anything different. Try tapping out from inside the gearbox with a suitable sized socket as a drift.

Martin C.

Thread: Standard dead length Crawford collets
04/05/2019 15:27:37

I have obviously forgotten about it, I'll put it down to age and time passing.

Martin C

04/05/2019 15:15:18

I think I gave a copy to Tony at Thought it would go well with his archives. That may be how you got a copy. I downloaded it and printed it off years ago but have not found it online since then.

Martin C

04/05/2019 13:01:11

Sorry about the scribbling on some pages. I didn't know at the time that it was going to be a useful historic document.

Martin C

Thread: Stainless Steel Metric Fasteners
20/04/2019 17:32:12

I have bought them for work in the past from RS or Buck and Hickman. Not necessarily the cheapest but RS always delivered next working day so suited urgent requirements.

Martin C

Thread: Backlash
20/04/2019 17:27:26

Typical method for CNC is to set up a dial indicator. Move towards the indicator until it moves a suitable amount to be sure it is off its stop and set it to read zero. This is the zero position. Reverse away from the indicator and back to zero to check zero is correctly set on the indicator, repeat as necessary.

Move forward another mm or other suitable distance to ensure the indicator moves away from zero then back to the zero position. The difference on the indicator from zero is the backlash value. If you can't enter this value into your program then calculate the number of steps to move this distance and add them to the reverse move.

Repeat the above with the backlash compensation and check the indicator returns to zero when the reverse move is made.

It is probably a good idea to reverse the direction and check backlash from the other way as well.

Martin C

Thread: Gyroscope origins
17/04/2019 08:23:45


Martin C

Thread: Telescopic bore gauges
17/04/2019 08:20:34

I agree with the two earlier posts regarding dial bore gauges. Yes they are fiddly to set up and to some extent use, it is also possible to misread them. They do however give repeatable results that do not rely on good feel. Cheap telescoping gauges can feel like they need stripping and polishing inside to improve them.

If you need to bore pockets for bearings the dial type may be a good choice for you. As also stated above it depends on a lot of factors to make the decision of what is best for your current needs. When a lot of similar sized holes are required a three point micrometer bore gauge with checking and setting ring may be useful but this tends to be for industrial quantities.

Martin C

Thread: Smart and brown lathe
15/04/2019 18:42:41

Join the two previous posts and you've got a model m that belonged to the Atomic Energy Authority.

Martin C


Edited By Martin Connelly on 15/04/2019 18:43:15

Thread: Removing a grub screw
15/04/2019 18:33:10

If it is in a through hole then a right hand drill may catch and drive it out of the hub.

Martin C

Thread: A close shave or why safety glasses are a must
10/04/2019 10:34:00

Two incidents come to mind from work. I was about to drill a small hole in a stainless nut for locking wire. I asked a nearby workmate to put his glasses on but he was reluctant so I insisted and wouldn't start until he did. Once started (using a high revving pneumatic drill) at some point the small drill disintegrated and a piece hit the workmate just below his glasses on his cheek. He thanked me for insisting on tbe glasses.

Another workmate was releasing a luggage elastic from something and it slipped from his hand. Tbe end swung around the structure it was on and hit the centre of one lens of his safety glasses with enough force to knock them back and cut his eyebrow area. Blinking would not have helped there.

Martin C

Thread: Further Adventures with the Sieg KX3 & KX1
10/04/2019 10:19:58

A simple but effective way to set z height is with a ground dowel, 10mm for example. You manually lower the tool to about 9mm above the surface you want to be z=0. You then creep up the z axis until the dowel just fits under the tool and set z=10 (or whatever your dowel is). A bit more time consuming than a tool setting switch but if you have plenty of time but money is tight it is an option.

Martin C

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