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Member postings for not done it yet

Here is a list of all the postings not done it yet has made in our forums. Click on a thread name to jump to the thread.

Thread: Beginner needs help with Colchester Bantam Lathe
21/07/2016 07:14:01

 

All the start winding does is push the rotor in the same direction every time, and provide extra power to overcome the starting load

There is bound to be a slight (at least) difference in speed at which the start windings are turned off for forward or reverse.  The rotor is accelerating at the time, so the resulting force on the switch will be different, dependent on which direction of travel. Physics fact!

 

I still think that fault is caused by the run winding being out of circuit in that direction

 

If that were the case, please explain how the machine works OK at lower speed settings

 

 

 

 

Edited By not done it yet on 21/07/2016 07:14:59

Thread: SX3
21/07/2016 06:58:07

No disrespect to Ketan, but ask somebody at axminster, too? Nothing like getting both sides of the story before making any fair comparison?

 

And do remember that concentrating on the single main difference may mean missing a plethora of minor points. PRICE is not always a good indicator. SERVICE after the sale might easily be a deciding factor. Only you can ascertain which is the better machine/deal after you weigh up all the pros and cons for your particular situation.

Edited By not done it yet on 21/07/2016 06:58:56

Thread: Beginner needs help with Colchester Bantam Lathe
19/07/2016 07:48:48

There is a clear click when a bench grinder runs down and the start winding contacts remake. Quite possibly the OP might hear this continual clicking in and out for the start windings if one's ear can be positioned close enough to the motor?

It may be that the start winding contact springs are aged or worn? Changing them might effect a cure, but there is always the risk that the start windings may not be disconnected at full speed in the reverse direction and result in a motor burn out.

The cross-over points for 2 and 4 pole motors and required starting torques are discussed in this link, and may be of help (but I doubt it smiley!

http://www.engineeringtoolbox.com/electrical-motors-torques-d_651.html

I don't know enough about motors, but I do know I prefer 4 pole to 2 pole varieties!

Thread: warco lathe quick change
18/07/2016 07:02:09

Do think carefully before going for a set. You may consider a set as good value, but the question a new purchaser may not be able to answer definitively is 'Do you need every one of those holders?'.

I made that mistake, it being that I will likely never use the knurling attachment as I will be making the 'scissor' type which is far superior to the 'push' type. That one holder meant the set was no better value than spending far less, initially, and obtaining (or making) more standard holder's later. Other possibilities are that you may already have a parting off tool or would, in hindsight, prefer a different sized blade. Just a couple things; there may be others.

Thread: I'm looking for a supplyer
17/07/2016 18:54:41

It makes not a jot of difference whether measured in Imperial or metric units. Everything on this planet can be measured in either units!smiley

Thread: Bee Keeping
17/07/2016 18:48:56

how are bees affected by Glycophosphates?

 

You are referring to glyphosate (monsanto 'round-up'?  That is a herbicide, not an insecticide. I'm not aware of the effects on bees, if anything seriously deleterious, but it is bad news when used in large quantities on GM crops supplied by monanto as 'round-up ready'.

 

The idea is that weeds can be controlled without affecting the crop. Unfortunately some weeds are becoming a huge nuisance because they, too, are either already resistant to glyphosate or are becoming more so - requiring ever greater doses of the herbicide. Not good, because glphosate has greatly increased the incidence of de

formed offspring in mammals (humans in Argentina and also farm animals that are fed on those crops).

 

 

Bad news as the levels of glyphosate in the food chain is caus

ing concern for hum

an health. They may well have shot themselves in the foot as this herbicide has been in use for decades and is now showing up these nasty effects because of their GM activities and increased use on food crops. Attention, too, for dessicating crops such as OilSeed Rape, prior to combining. No not good news all round for monsanto!

 

 

 

 

Edited By not done it yet on 17/07/2016 18:49:52

Thread: Ideal Beginners Lathe?
17/07/2016 14:10:15

Although I have never used a milling attachment (had a milling machine), I agree with Ajohnw. Shame perhaps, as I will be selling my CL500 shortly,  but I am giving my honest response. Had it twenty years and never really used the milling part. Replaced with a Raglan LJ. Now replaced my old mill with more 'old metal' which, IMO, was far better than buying new or second hand chinese.

Edited By not done it yet on 17/07/2016 14:11:32

Thread: New three jaw chuck
17/07/2016 13:59:52

My recommendation? Get your Pratt Burnerd repaired or overhauled. Or think of more money to replace with an item ofequivalent quality.

Thread: Bee Keeping
17/07/2016 13:47:49

I have kept bees for about 15 years. Although some seem to have continual problems with the art/craft, beekeeping is quite simple, even though some seem to think otherwise.

 

With regard to wasps - they are a beneficial insects, and nests should not be destroyed unless they are a nuisance or pose a health risk. Wasps consume large quantities of unwanted pests, grubs, etc, are good scavengers and generally help to balance the environment at bug level.

 

Bumbles are one of many bee species. They are, like wasps, are 'eusocial', which means they live communally but the colony dies out at the end of their active season. Mated queens overwinter buried in north facing banks, etc (so they don't wake up too early in the spring due to unseasonal sunny days warming them up). Hibernating queen wasps will survive atlery low temperatures - think here freezer temps!

 

Bumbles will not normally use the same nesting for a few years, so once used any bumble nests put out for th

em should be thoroughly cleaned, preferably left as a mouse home, before using in another position in the garden.

 

There are loads of solitary bees and wasps out there which are useful polinators (a

s well as flies, etc). An earlier poster was spot on re reduced insect populations. Of late, particularly down to the temporarily banned neonicotinoid systemic insecticides. They kill any species, not just the real 'target' pests. I remember, as a child (and later as a motorcyclist) that on warm summer nights it was like snow flurry, with moths and other insects illuminated by the vehicle lighting. It has worsened much more in latter years due to these new ''improved'' insecticides. IMO, they should be banned permanently, particularly as we do not know if they are truthfully safe, even to humans.

 

 

Questions?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited By not done it yet on 17/07/2016 13:54:18

Thread: Repairing iron pulley wheel damage
14/07/2016 18:08:38

Can't see the pics here or on the link, but do drill stress relief holes if there is any chance the cracks can propagate.... safety may well depend on rotational speed ...

Thread: What size generator.
14/07/2016 09:08:07

Think here that a 5HP motor, partly loaded, on single phase domestic supply might well empty your mains supply at start up! Lights go dim and possibly the main supply fuse will be activated if the wife has the oven and a few other loads in operation at the same time. My large stick welder or 2HP compressor both noticeably dim the lights momentarily at switch on.

You would likely need a rolled steel magnet framed generator, not a rotating field genny, to avoid a stall situation at start up. To be safe, I would hazard a guess at ten times running current? That is why most larger motors are three phase. I would guess that a three phase motor would start with much less overload capcity but I don't know how much less.

Soft start, such as a VFD could provide, is a definite advantage. I would suggest borrowing, or even hiring, a generator to check out suitability, after seeking advice from a generator hire company.

Thread: three phase motor current
14/07/2016 08:46:41

Resistance, inductance, reactance, back emf, Flemming's left and right hand rules, magnetic field strength and saturation - and possibly a few others - all inter-react dependent on speed.

Andrew's thought experiment emulates starting current required for these motors. Until it gets going, Ohms law applies initially (apart from not being at constant temperature) along with building and collapsing induced magnetic field (due to A/C frequency), dependent on the structure. Hopefuly zero rotation does not persist for long or the dreaded smoke will escape!

Motors are designed with all things in balance at their operating conditions. One certainly cannot continue to increase the frequency ad infinitum and expect to extract useful power.... One might even think of an extreme, like induction furnaces, where the electrical energy is coupled to a small lump of metal which simply heats up, when the induced fields are concentrated on the target.

Thread: drill sets
12/07/2016 11:42:14

I have a set of drills I bought in Ca. I very rarely use them for anything other than go/no go checks. They are my complete standard set of 136(?) drills in Imperial sizes. The rest are ones I have bought or picked up at sales. Some good and some less good. I keep tapping sized drills with the appropriate taps as 'sets'.

 

Over the years I have acquired several boxes and keep a couple of these filled with the drills I use regularly. I would no longer buy a set, but just buy in good quality drills in the sizes I need. I do like my part-set with morse taper shanks, but for best accuracy they do need a good sharpeng regime.

 

 

These days I might consider a complete metric set drills if a good set were to become available at the right price, but I would say that, particularly for the larger sizes, a good means of sharpening is a greater priority than buying in whole sets, of which only a few are used.

Edited By not done it yet on 12/07/2016 11:45:57

Thread: have 4:1 from 3000rpm dropping down to 750 rpm what gears to get 600rpm
12/07/2016 04:35:29

Ahh, I see, bodge. Thread started on the wrong track. The real issue was substitution of an inappropriate drive? Too powerful, too fast (for a plain bearing spindle?) and likely excessive radial loads, beyond the bearing limits and possibly in the wrong direction? Nowt better than proper design, rather than trying to beat the mechanical constraints of the installation.

Thread: Power Transmission Capability of Mower Variable Speed Drives
11/07/2016 13:31:53

What happened when the diameter approached zero? Always flat out?

Certainly good in some instances, but not for all situations, for sure!smiley

10/07/2016 20:44:50

Both Raglan lathes and mills had about a (claimed) 6.5 ratio, so say 6:1 with the variable speed pulleys. Selecting back gear on the lathe can be a pain, but then gives another approx 7 1/2 speed reduction. On top of that I have a VFD fitted on mine (lathe has a 415V three phase motor, so no real option) and all that makes speed selection nooo problem at all! Far better than changing belts on pulleys! One of the (several) reasons why Raglans were so much superior (and costly) than a my Ford!

Scooter systems might be troublesome? Don't want the lathe spindle speed to change with load?

Thread: keyway on involute cutter
07/07/2016 08:30:32

It might just be an economy measure to make the arbors cheaper?

Andrew,

It may not be the original arbor, but is likely. Doubt it was a cheap economy measure, if original, as it is a Centec.

Thread: Swarf!!
06/07/2016 21:34:03

If I know that I am going to demonstrate geiger counters and radioactivity, I take along my dad's old wrist watch. It registers more counts per second than some of the school sources.

Although I was always 'clean', I had my supervisor hunting for contamination on my lab coat until he got fed up with searching. That was 40 years ago, mind. I remember it was the high specific activity tritiated acetic anhydride (that someone contaminated the lab with) that got everyone P bottles for a couple of weeks! No geiger detection, but sure messed up the main scintillation counter at the time, as all our stock of counting vials were seriously contaminated both inside and out.

Thread: have 4:1 from 3000rpm dropping down to 750 rpm what gears to get 600rpm
02/07/2016 23:36:06

Just get a motor speed controller? Fit a RPM indicator (a fiver, or so, from epay). Then choose any speed you fancy.

 

Questions might be ' Why 600rpm?' 'What tolerance?' 'What type of prime mover?' 'AC or DC, if electric, and brushed or brushless?' 'What space restrictions?' Etc.

 

As mentioned, V belts do not drive on the bottom of the groove. Only flat belts do that! Washing machine motors, working with multi v belts, can have a huge speed reduction in one go.

 

Yes, it may be easier , and possibly cheaper, to control the motor speed....

Edited By not done it yet on 02/07/2016 23:36:44

Thread: Swarf!!
01/07/2016 16:43:31

You could always set up a home micro-foundry and recycle it yourself?

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