Member postings for Neil Lickfold

Not sure if this has been covered before.

But to get a very precise diameter, I set my compound slide on a 1/2 deg aprox angle.

Then when I am close to the diameter I need, I use the compound slide to make the X movement.

With this set up it then becomes possible to get to micron sizes.

You have to either take some test cuts or use a dti to figure how much each graduation on your cross slide takes off the diameter. Also make sure the cross slide gib is not too loose as well.

I use this method for sizing pistons to F3D (6.5cc race engines) where a difference of 0.003 mm in diameter is either too tight or too loose and worn out.

Neil

I brought an Eric Drive VFD that is programmable for acceleration and deceleration .My motor is a 550w 1440 RPM.

I have a 2 way switch where the original forward reverse switch was. Above the lathe is the control box mounted in a housing box. On there is the main on off for the VFD, and the pot with some numbers representing Hz approximately.This controls the motor speed. The control on the VFD displays the actual HZ .I have the hertz range set from 30 HZ to 60 hertz. That along with the belt changes, I do not need to go into back gear any more.

I have not done it yet, but intend to connect an adjustable micro switch, so that when it gets to the switch the motor stops. I have mine ramping down and breaking, and set that to 0.2 seconds. I also have the start ramping at 0.2 seconds as well. The intention is to use it for cutting internal threads and having it stop at about the right place.Any quicker at stopping,and you risk the Chuck coming undone.

When setting up the VFD there are parameters like the Max motor current etc. When set up ,it still has loads of power even at low RPM's. The only waning is that the motor can get hot if continually run at very low rpm's.In these situations, they recommend adding a small fan to keep the motor cool.So I have my min hz set at 30 as recommended by the place that sold the motor and VFD unit.

My only wish is that I should have gone this way much sooner that is for sure.

Neil

My motor had problems back in 2005. I thought it was a cap problem, so took the motor off and to a place to check it out. The man un soldered the cap,tested it and said it was all fine. I took it apart, he looked at the brushes in the switch, although not perfect he said that it still should have been working. I put it all together, he soldered back on the cap, connected some wire and worked fine. He said that sometimes over time, the soldered connection of the wires to the cap need re soldering. I took it all apart as I thought that there was a problem with the centrifugal switch. I was wrong.

It worked faultlessly until 2012, when everything stopped again. This time it was the forward and reverse switch that went. So I retired the motor and put on a 3phase motor with a VFD drive. The motor still works fine, and is sitting on the shelf as a spare for something one day.

There are a new generation of boring bars that have vibration dampening technology. Some have a carbide or some other heavy metal that vibrates and counteracts the vibration from the tool. Another one in the small bar sizes is the Dynamic series from Kyocera, or the Dimple series from Mitsubishi.They make them in steel and carbide shanks. Carbide costs a lot more but has a lot longer diameter to length ratio.

After using the vibration dampened tools, you will not want to use standard tools again.

I have made dampened tools to external turning for tools that needed to have along over hang.

To test the effectiveness of the tool in making it , I tap the side of the tool and if it does not ring, it will be fine.

In the small bars I like the ones with a sort of triangular shape that allows 3 cutting edges instead of the 2.

Neil

My myford has a ground lathe bed, so does a friend's lathe. Mine is a super7 made around 1974.

The only slide that has scraping is the compound slide. Not sure if that was original or done by the previous owner.