By continuing to use this site, you agree to our use of cookies. Find out more

Member postings for Les Jones 1

Here is a list of all the postings Les Jones 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: Chester DB8
09/01/2021 15:36:43

Just click on the camera button. (The next to last on the top line.)
That will display your albums and the picture files in them.
Select the file you want to display in your post and click on the OK button.

Have you measured the length of the belt path round the pulleys ? This would be a good approximation to the belt length.

Edit. I have just noticed your last post that you gave the number of teeth on the pulleys. These are the same as on the DB-10G.

Les.

 

Edited By Les Jones 1 on 09/01/2021 15:40:16

Edited By Les Jones 1 on 09/01/2021 15:41:17

Thread: VAT changes post Brexit
08/01/2021 22:11:47

I ordered one of these this morning as a result of LINK REMOVED (I also ordered a set of 15 ER11 collets for about £12.00) I too was wondering if there be additional charges when it arrives.

Les.

Edited By JasonB on 09/01/2021 06:57:51

Thread: Chester DB8
07/01/2021 20:25:23

Brian has said that a different length belt with the 1.5 pitch part of the specification seems to fit the pulleys.
(This wat in the post on the 7th at 12:40)

Les.

Edited By Les Jones 1 on 07/01/2021 20:25:43

07/01/2021 19:46:02

Hi Jason,
I think it may be better if Brian confirms this measurement by using string or tape round the two pulleys in place of the belt before he orders one.

Les.

07/01/2021 17:35:19

Many thanks Jason for explaining that. (I never even thought of dividing the measured pitch (In mm) by Pi.) The thread that Michael linked to suggests that the DB8 belt has 124 teeth. As Brian has given the diameter of the pulleys if he tells us the number of teeth on one of them we should be able to tell if the 1.5 pitch belt is the correct one.
One other point is that the Sieg C4a and C6 both use the same timing belt. This makes me think that the DB8 is based on a Sieg C4A and the DB-10G is based on the Sieg C6.

Les.

07/01/2021 15:02:59

The belt for the DB-10G is called a 1.5 * 124 * 15. I think this is the same belt that is used on a DB8 lathe. I think the 1.5 part is related to the pitch but it does not seem to have any simple relationship with either metric or imperial units.

For comparison with the DB-10G the the small pulley (On the motor) has 19 teeth and the OD is 28.1mm. The large pulley has 90 teeth and the OD is 134.25 mm The distance between the pulley centres is 154mm.

Les.

06/01/2021 22:24:50

Hi Michael,
Your link has given the required dimensions of the belt which is a good start as Brian does not seem prepared to to take any measurements. This seems to be the same belt as on my Chester DB-10G (Chester were no help when I needed to replace this belt.) When I measured the tooth pitch of my old belt I thought it was 3/16" (= 4.76mm) But I found it was called 5mm pitch which is probably what it is under tension. RS stock one that has the correct pitch (5mm) and number of teeth (124) but it is 16mm wide as opposed to the correct belt which is 15mm wide .Brian would have to measure the distance between the flanges on the motor pulley to see if this would fit.

Les.

Edited By Les Jones 1 on 06/01/2021 22:25:42

06/01/2021 15:09:29

You can thread some string or tape round the two pulleys to get a rough idea of the length and measure the width of the pulleys to get a rough idea of the belt width. you may even have a piece of the belt that was still intact enough to measure the tooth pitch.

Les.

06/01/2021 14:17:30

As John says if you measure the belt length, width and count the number of teeth there will be a much better chance of identifying the belt. I have a Chester DB-10G and it is just possible that it uses the same belt.

Les.

Thread: Myford super 7 lathe tripping consumer rcd
02/01/2021 16:04:50

Andy. That is a good theory.
Nick, You could prove this by connecting a lamp or some other load to the lathe circuit. If that trips the RCD it probably proves Andy's theory. Tracing neutrals in a consumer unit can be difficult if it is fully populated.

Les.

Thread: Wiring for Parvalux Geared Motor
02/01/2021 14:35:56

I think John's and Nick's diagrams are probably correct. They are both functionally the same. The fact that the mains polarity is shown different does not matter. (Either way is OK.) If the motor rotates in the wrong direction then swap the power wire to the other white wire. (That is the Live in John's diagram. The neutral in Nicks diagram.) If you want to know what the thin black wires are then you will have to dismantle the motor. I can see three possibilities. They could go to a thermal fuse, A thermistor for monitoring the temperature. (This is not very likely on an old motor,) They may also may go to a centrifugal switch which disconnects the start winding when the motor gets up to speed. If it is a centrifugal switch it is faulty as it should measure almost zero ohms when the motor is stopped.
You could do a rough test of the capacitor by connecting it in series with a 60 or 100 watt incandescent lamp. (If you still have any of them.) The lamp should light but not quite as bright as when connected directly to the mains.

Les.

Thread: home made forge
01/01/2021 12:41:10

Hi Derek,
I can't remember the exact air pressure I use but I think is is only about 20 PSI. The nozzle is designed to suck up the oil but I use gravity feed to get a greater flow. I also heat the oil to about 100 degrees C so it atomises better. (The oil is not vaporised in the nozzle. it comes out as a fine mist. I use the water heater part of an old steam press to heat the oil. I start the burner with propane as the oil mist is not easy to ignite. Once started it burns without smoke. (But it is quite noisy.) I had to buy the nozzle from the US as I could not find a stockist in the UK.

Les.

01/01/2021 10:47:37

I have made a waste oil burner for my furnace using a Hago Delavan syphon nozzle.
This is a link to the design of my burner but you will find some other designs on the web.
This is a link to the blower system I used.

Les.

Thread: Reverse Sewing Machine Motor?
04/12/2020 11:48:36

If you can open the motor it should be possible to reverse it. The mains is fed to one end of each field winding. the other end of each field winding is connected to one of the brush holders. To reverse it you need to swap over the connections between the field windings and brushes. This will probably involve extending the wires from the field windings to reach the opposite brush holder. It is possible that there are also small RF chokes and capacitors fitted inside the motor to reduce interference. If this is the case you will probably have to post pictures of the inside of the motor so we can tell you if this has any bearing on the way you swap over the connections.

Les.

Thread: ML7 toolpost - Turns Under Load
14/11/2020 19:28:30

You could try my suggestion by making a washer out of some thin metal. The hole size would be the diameter of the outer edge of the three grub screw holes.

Les.

14/11/2020 16:58:41

Looking at the marks from the engineers blue in your post at 16:09 today the items are making contact more towards the centre. If the same clamping force was applied near the edge of the block it would have more effect at preventing rotation. I think I would be tempted to take a skim off around the centre of the tool post so that the edges were making contact.

Les.

Edited By Les Jones 1 on 14/11/2020 16:59:21

11/11/2020 18:42:36

Is the threaded post a larger diameter at the bottom than the threaded part ? If so are you sure that the tool post block is not clamping against the step on the post rather than the top of the top slide ?

Les.

Thread: Sieg Milling Machines
11/11/2020 16:55:32

I have a Seig x3 milling machine and am totally satisfied with it. I bought this (And other items.) from Arc euro trade and found them a very good company to deal with.

Les.

Edited By Les Jones 1 on 11/11/2020 16:56:26

Thread: LED Constant Current Source Scheme
11/11/2020 09:09:58

Hi Gene,
The idea does not use any current sense input on the chip. It uses the feedback input for voltage regulation. In both cases (Buck & boost.) the adjustable voltage version would be used. The chip adjusts it's output attempting to maintain 1.25 volts on it's feedback input. So by choosing a resistor at the bottom end of the chain of LEDs that gives a voltage drop across that resistor of 1.25 volts with the desired LED current and connecting that point to the feedback input means that the chip adjusts it's output voltage to a value that gives a current through the LED chain that produces a drop of 1.25 volts across the resistor at the bottom of the LED chain.

Les.

10/11/2020 22:06:44

I have used cheap step up switching voltage regulators (Based on the LM2577S) modified for constant current output. This is a link to the modification **LINK**
The same principle could be used with buck regulators The disadvantage of this idea is there is a 1.25 volt drop across the current sense resistor. This is not much of a problem when driving a series string of LEDs but for driving a single LED it wastes too much power.

Les.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
ChesterUK
JD Metals
Eccentric July 5 2018
Warco
cowells
emcomachinetools
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest