Member postings for John MC

Hi Emgee, the motor is driving a G H Thomas designed sensitive drilling machine. Originally the motor was mounted so the belt could be crossed to get the correct rotation. I have now mounted it in the conventional mounting position for a small drilling machine hence the need to reverse the direction of rotation.

I built the machine when GHT described it in ME, 1983-4? The motor came from K R Whiston, remember them?

The drill could do with a little more power, 88w at the moment, starting torque could be better, once up to speed a 1/16" through steel is OK. Been looking for a more powerful motor, no luck yet.

John

Kudos to Emgee, the link was just what was wanted, motor now running in the right direction.

Now I have had a good look at the motor, reversing the position of the rotor would not be a good idea, the innards are not symmetrical.

Once again again, thanks Emgee.

John

I bought a cheap bench grinder a few years ago. First thing I did was bolt it down otherwise I would be chasing it around the workshop! That done it would then shake whatever was on the bench onto the floor! The principle cause of vibration was the wheels, out of true both radially and axially. I had two old lathe top slides of fixed together and clamped to the bench, with a diamond I was then able to true the wheels. Not perfect but usable. I used this awful quality grinder with an equally awful drill grinding attachment as my main means of drill sharpening for many years with much better results than the awfulness of the equipment might suggest.

One suggestion I would make regarding the nice looking work rests, make something that will stop the rests digging/tipping into the wheels should the fastenings loosen, (assuming it has not been done). I have witnessed two bad workshop accidents in my employment, one was as described on a large offhand grinder.

John

Many thanks for the replies. I don't think turning the motor over will change the direction of rotation! I'll dismantle the motor and do the necessary next week and report back.

John

Morning all. I need to reverse a small (240v, 1/10hp) motor. The motor has 3 wires and a permanently connected capacitor. The wiring diagram for the motor tells me it is non-reversible without dismantling. So I googled the problem and found a video that suggests that all I need do is remove the rotor and replace the opposite way around. Is it really that simple?

John

Could work if you can find a spring with suitable wire diameter. The wire needs to contact the flanks of the thread about halfway up the depth of the thread.

John

For absolute accuracy the screw should be centered from the threads PD (pitch diameter). A tricky thing to do. The way I would do this is, as suggested with a DTI with a "big foot" on the outside diameter, then check with wires what the PD is doing. A bit of a faff but well worth doing for absolute accuracy, especially if the method of manufacture of the screw thread is unknown.

Incidentally, the same applies to gears, true up on the OD initially, then check the PCD.

John

From memory I believe the whole "dovetail" in the tool post moves in and out to lock and release the holder so some very accurate work was required to ensure repeatable setting. Yes, they were (are?) expensive, again if memory serves, half as much again as a Dickson.

A large local, to me, engineering company had Bergstrom QCTPs on there very hard worked NC lathes, the tool posts where replaced with Dickson products because of wear in the Bergstrom posts.

John

On the question of whether or not the tool holder should be pushed or pulled against the tool post for rigidity I quote from the Bergstrom Quick set tool post sales literature;

"Tri-lateral design. The large contact surfaces ensure positive clamping without vibration and chatter."

Sales literature here; http://www.lathes.co.uk/bergstrom/

Rigidity in any machining operation is fundamental to success, I would urge anyone buying a QCTP to consider this.

John

Newton's third law?

In a Dickson the piton pulls and the dovetails push in equal amounts.

In some others the dovetails pull and the pistons push.

Is there really a difference in rigidity?

Most definitely, the loads from the cutting point of the tool need to be fed into the machine. Any lack of rigidity (stiffness?) and gaps in the path will cause vibration.

"Fancy tools and toolholders are a mirage to deceive the beginner.
Don't get a QCTP until you have several years of experience or more money than sense. You shouldn't be in such a hurry that you need the 'quick' part and if you are too lazy to set the height with shims you are in the wrong hobby."

Good point there, While I have had QC tool posts on my lathes for a long time now many years ago my first "proper" lathe was a round bed Drummond No chance of buying a QC tool post on my wage so I had a selection of shims that lived permanently under my favoured tools. Changing tools was almost as quick as a tool change with a QCTP!

John.

My advice when buying a QC tool post would be to make sure the tool posts "mechanism" pulls the tool holder into the post on locking, as a Dickson does. Some do the opposite, that is to say the tool holder is pushed away from the post. This will have a significant effect on rigidity.

John

Had bother with mice a few years ago. The cat didn't seem interested. Humane traps caught the little b*****s, I freed them 100ft from the house but they came back, the wife was convinced they were the same ones! Tried "the Little nipper" (other brands available). The trap "fired", the bait disappeared but no mouse. Reluctantly tried poison, end of problem. I have never found a body or detected a smell.

John

I have Dickson tool posts on my lathes with some genuine and some"foreign" tool holders. Never had a problem with them being gripped by the tool post. What I have seen though is distortion of the top hat shaped part that pulls the holder in to the tool post. This component is somewhat thin walled where the hole that the cam passes through. Seemed to be a problem with the smaller versions of the tool post. Worth checking I think as the most likely culprit to insecure clamping. The posts are case hardened so would, I suggest, need a huge amount of work to "wear out".

I've also checked the dimensions of a number of my tool holders, genuine vs copy, significant variation in dimensions except for the angle of the "angled" dimensions and their positions , all the same as near as I could measure. The tool posts have no problem gripping any of them.

The checking and repair for the problem I have suggested was the job of the apprentice at an engineering company I worked at many years ago.

Agreed I should dismantle the clocks to clean them. If my ultrasonic cleaning of the more or less complete mechanism doesn't restore the 8 day running then one of them will be disposed of and the other will go to our local clock and watch repairer for proper attention.

As has been pointed out, the cleaner is quite large so requires more fluid than the more modest sized models, I could be paying £50 - £100 to fill it up so I am looking for a much cheaper option.

In the past I have tried an ammonia based cleaner in it..................

John

Many thanks for the replies, I like the idea of a gentle warm in the oven after cleaning to dry off. What I need is something "neutral" that cleans the muck off the parts but does not touch the metal. I've seen an antique watched by ultrasonic cleaning, wouldn't run after cleaning, a watch specialist knew immediately what had been done. The cleaner had etched everything, it rattled after cleaning but it was very shiny!

I lubricate with "clock oil" or so it says on the bottle. There is definite evidence of oxidisation after a few years. Even though the clocks (spring driven) are in cases dust gets in. A good clean and a lube gets them going again.

John

Good morning all, I'm looking for some recommendations for ultrasonic cleaning fluids. I have a couple of old clocks that I periodically (every 5-6 years) would put in a cleaner then lubricate when they would not last the week on one wind up. This I could do at work before retirement.

I acquired a cleaner a few years ago, it has a fluid capacity of about 10litres/2 gallons. I've used various household cleaners diluted with water with varying degrees of success. The problem is drying the cleaned parts, rust could appear before I had dried the part and get protection on it!

So, what I am looking for is a low cost fluid that will perhaps leave a protective residue behind, is there such a thing?

John

Some good points there, my trailer winch ratchets both ways and there is plenty of control so a gentle put down is easy, just tried it! Unlike the electric type in the OP's video. That seems to be the problem with the cheap end of the market, the better hoists have much more sensitive inching.

As for the difference between pulling and lifting, point well made and should be remembered. Not a concern here, I'll be lifting about 40kg maximum with something rated well in excess of that. My main concern was the capacity of the wire rope, its well in excess of the rated capacity.

There is a safety warning on the winch reminding me not to lift humans!

John

Like the idea of a scissor lift (versatile) but don't have the space around the machines. What I will do is attach an upright to the lathes (Colchester Triumph) pedestal with the lifting kit attached to it, I'll arrange matters so it can reach the mill as well.

A couple of further points,its been suggested that the hand powered trailer winch I'm going to use, good for 800kg, is meant for pulling, not lifting, so I should be careful. Whats the difference between pulling and lifting?

I like the of the eBay jib, but do not want to attach to the ceiling structure. I would assume all the necessary "strength" calculations have been done for the jib, if a design were to be published this would surely be necessary?

John

Some good ideas there, just thinking of something like that for my workshop, not getting any younger! Watched the video, the electric winch seems a bit abrupt, I am thinking of using a small hand powered trailer winch.

Also, if the chuck was lifted with a "U" shaped bracket, on its side. The chuck gripping one leg and a lifting eye arranged on the opposite leg on the vertical centre line, the chuck could then be lifted in the correct orientation for fitting to the spindle nose. This link shows what I have tried to describe;

https://moderntools.com.au/products/sky-hook-industrial-lifting-devices/

Scroll down the page and you will see what I mean.

John

My second lathe of many years ago was a round bed Drummond, the almost complete set of change wheels for that had a 63T gear for metric. No chart but worked out the trains soon enough thanks to the subject being taught at technical college, I wonder if its taught now? Interestingly the error in pitch using the 63T rather than a 127T gear was minimal, way smaller numbers than the accuracy the lathe was capable of.

John