Member postings for Paul Lousick

I have been looking for a used 10" or 12" rotary table but cannot afford the price tag. Up to $1000. I believe that all of the big ones are built much better than the cheap Asian clones. I would not like to destroy one to make another.

Why not just use one" as is" as Hopper has said. this is what other people do.

Paul.

The color of gun metal looks similar to bronze when machined and is slightly darker in color than brass. It is very easy to machine. The base casting (upper left) is made of gunmetal and the spring retainer (middle piece with bolts) is made from brass.

Neil.

Back in the early 80's we used to be able to buy a water injection unit that added a small amount of water to the air/petrol mixture from the carburetor. Supposedly to cause a better fuel burn. I also remember something about a similar system being used in early fighter plane engines.

Paul.

Roger,

Backing off of the engagement lever not only increases the backlash but increases the stress on the teeth because the load is only taken on the tip of the tooth.

I was conventional milling with the rotary table to try and eliminate backlash and was actually applying pressure by hand to keep the worm gear in mesh when the breakage happened. I did not notice that the worm engagement was coming loose.

Problem was that I was using a 6" rotary table to machine a 250mm dia x 16mm thick piece of boiler plate (460 MPa) which is not easy to machine. The Rotary table was not one of the cheap Asian clones but a good one, made in Japan. To replace it I bought one of the cheap clones but was not as good as the original. Since then I have replaced the worm gear ($150) on the original.

Paul.

Roger,

Backing off of the engagement lever not only increases the backlash but increases the stress on the teeth because the load is only taken on the tip of the tooth.

I was conventional milling with the rotary table to try and eliminate backlash and was actually applying pressure by hand to keep the worm gear in mesh when the breakage happened. I did not notice that the worm engagement was coming loose.

Problem was that I was using a 6" rotary table to machine a 250mm dia x 16mm thick piece of boiler plate (460 MPa) which is not easy to machine. The Rotary table was not one of the cheap Asian clones but a good one, made in Japan. To replace it I bought one of the cheap clones but was not as good as the original. Since then I have replaced the worm gear ($150) on the original.

Paul.

WARNING.

Ensure that the worm screw is adjusted so that it is fully engaged with the worm gear when you are the rotary table.

The engaging ring (the one with the small lever) has a tendency to undo when taking heavy cuts. The vibration caused by the flutes on the milling cutter will undo the ring and the worm will only be engaged with the tips of the teeth on the worm gear. The gear is only made from cheap steel and the teeth can break (see photo). The clamp screw (screw with small tee handle) which is supposed to lock the engaging ring does not always work.

Paul

Has anyone used a RepRap Prusa i3 printer. (Pros / Cons, etc)

Available as a kit or fully assembled. Lots of replacement parts available on %-bay

Paul.

Which series and episode ?

We have Antique Roadshow in Australia and I checked the latest episode that was released here and did not find anything. We may not have your latest show yet.

Paul

If the job is firmly clamped in a vice which is fixed to the drill table prior to using a centre drill it should be in perfect alignment when you change it to a twist drill. No need to position over the pilot hole because it is already there.

Heat red hot with a gas torch, quickly clamp in a vice and bend or bend over an anvil or solid block of steel before it cools.  Use a longer piece of rod and hold with gloved hand or by a pair of pliers. You can easily bend rod up to 10 or 12mm dia by hand when it is hot.

Edited By Paul Lousick on 27/03/2016 12:33:28

John,

I like your suggestion of using a milling machine for rough machining a cast or forged crankshaft to cut thru that tough outer layer.  A rotary table (if you have one) would be a better way of rotating the shaft than by turning it by hand, especially if if is a bigger crankshaft. Then do the finish machining between centres on a lathe.

Paul.

Edited By Paul Lousick on 23/03/2016 21:48:19

An external hone can be used to finish the shaft. There was an article in an early edition of ME for making one. Do a Google search for DIY designs.

This one uses a stone from a car cylinder hone.

Agree with Colin, you will need a temperature difference of more than 200deg C.

Liquid Nitrogen at a temperature of -200 deg C will shrink a 4" diameter mild steel shaft by only 7.6 thou.

I intend to shrink fit a cast iron cylinder into the steam chest of my traction engine by heating the steam chest in the BBQ to about 250 deg C and freezing the cylinder in the refrigerator to -15 deg C.

Paul.

Hi Jeoff,

As stated above, have the castings replaced.

If, as you have said, there is "sufficient good metal for the wheels", the holes could be filled with with something like Loctite Fixmaster steel putty which is a steel reinforced, two-part epoxy which can be machined, drilled and tapped.

Paul.

It depends on how strong a joint you want to achieve and how much load it is to withstand.

CRC Freeze Spray instantly cools small components. It aids in the assembly of close tolerance or interference fit configurations and is a helpful tool for many other engineering and automotive applications.

Loctite Threadlocker Red 271 is designed for the permanent locking and sealing of threaded fasteners and can be used for mounting bushes and bearings in housings.

Paul.

Edited By Paul Lousick on 22/03/2016 05:29:57

It is common practice that screws and nut orientation is only a representation of their finished position and it is virtually impossible to set a nut to an exact angle. The important thing is that it is tightened to the correct torque.

The problem falls back onto the inspector who has little experience and training and should not be in that position to start with.

Car road service mechanics have equipment which can break into cars without doing any damage.

Andrew,

Instead of using the link, try a Google search for: Robson super drill

or the Tooling site who is selling it: http://www.toolking.com.au/super-drill-pack-large-metal-drill-bit/

Paul.

Super Drill

An Australian invention that allows you to drill any size hole from 1/2" to 2" (12.7mm to 50mm) in steel and timber.

Designed to fit into your standard drill press the super drill works using 2 specially designed fully adjustable cutters to easily cut holes any size you need, using no more than finger pressure needed to get perfectly clean round holes every time.

Cutters are re sharpened using a diamond lap or hone and can also be replaced when they wear out.

https://youtu.be/N21yA0Y6T1A

There is a design patent on its manufacture but could be made for personal use.

Paul

Boilers usually have a clack valve (check valve) between the boiler and the pump or injector and an isolation valve between the clack and the boiler so it can be isolated if it is leaking steam/water back to the tank.

Is the tank higher than the boiler ? Water should not flow into the boiler unless the supply pressure is higher than the boiler pressure.

Paul.