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Member postings for John Baron

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

Thread: Cheap stepper motor couplings?
11/02/2016 21:39:01

I agree with the bit of hosepipe. I've used clear PVC fish tank air hose before now.

Incidentally the plastic coupling in the picture won't allow for any offset between shafts not in line.

Thread: Spare part wanted
11/02/2016 21:26:18

Hi Dave,

Brush failure due to overheating seems to be common on these motors. Usually because the copper pigtail joint in the carbon of the brush fails causing a bad joint which then becomes open circuit, forcing the current through the spring that is applying pressure to the brush. The spring which is not designed to carry the amount of current that it is now being forced to carry, starts to heat up and looses its tension. This allows the brush to bounce around on the commutator causing more sparking and subsequent heating leading to failure.

One fix is to turn a PTFE plug to be a tight press fit into the top casting, then drill and broach a rectangular hole to suit the carbon brush. A new heavier gauge spring to push on the carbon brush and a cross drilled hole at the back end for an insulated crimp blade, the type that you can crimp a wire in at one end and place into a terminal block at the other, used to hold the brush and spring in place whilst providing an electrical connection.

HTH.

Thread: Affordable CAD software?.
12/12/2015 21:26:44

Qcad gets my vote too ! Though Draftsight is good. Both are candidates for replacing expensive Autocad, but like any piece of software it takes time to learn how to use it effectively .

Thread: Avoiding stuck chuck - intermitterent cuts
12/12/2015 14:41:05

FWIW the Myford S7 lathes have a spindle lock !

Its that pin at the back to the left of the spindle change gear cover.

Since I don't seem to be able to attach anything I can't post a picture.

Thread: Laser edge finders
26/02/2015 21:07:22
Posted by Michael Topping on 26/02/2015 19:23:14:

Hi,

Has anyone got experience of the laser edge finders as sold by Chronos and others?

I am not getting the accuracy I want with traditional edge finders and wondered what sort of results these give?

Thanks

Michael

Hi Guys,

When I found that Aldi were selling a cheap laser pointer, I bought one and made my own. (See Photographs) I must say that I didn't expect too much from it, but was quite surprised by the results. Initially I thought that it was quite poor, since the dot was about 1.5 mm in diameter. Then I realised that there was a very very tiny black dot right in the centre. Maybe 0.25 mm, and that it was very easy to see the movement when simply tightening the head gib locks. The other thing that I discovered, was that it was easy to find the centre of a hole. By adjusting the hight I could make the circle ride on the hole edge, thus finding the hole centre.

Since I can't upload photographs, this link has the details. You will need to register to see the pictures.

http://www.woodworkforums.com/showthread.php?t=192205

Thread: Weather Warning for Hobby Machines
19/01/2015 21:20:29

Hi all,

With regard to the filters pointed to in the link, these are not intended to protect from voltage spikes or brown outs, but rather to prevent interference from the apparatus connected to the mains supply being fed back into the mains.

Every computer, washing machine, TV has something similar already built in to it, since it is required by law now.

The device that is required to suppress voltage spikes is a "varistor", these are available at places like "RS Components and Farnell Electronics" and are quite cheap. However unless you have the knowledge of how to apply them and the skill to fit them the devices that have them already built in them are a safer option.

Thread: Mystery Drive Belt
16/08/2014 20:21:40
Old washing machine belt. Probably Hoover twin tub from 1980/85 ish. I've dozens of them kicking about somewhere. They are about 8" long with the belt squashed. they are actually rubber with a woven fabric jacket.
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