Member postings for Sonic Escape

I found a nice die holder. It was rusty but I applied some rust converter and now it looks much better.

I'll try to summarize the main ideas so far:

1. There is no longitudinal play. Only 0.003mm if I push the chuck with both hands as hard as I can.
2. Radial play is up to 0.01mm measured at 10mm from the chuck. If I push it with one hand. Always return to original position. So it must be just metal bending not play? See the video bellow.
3. The main problem is the 0.120-0.130mm runout. This was confirmed with a test bar and two carbide mils. There is no improvement if I use a different socket hole of the chuck.
4. EasyZero collet nut is interesting but it can dial out only 0.05mm maximum.

I'm looking for a C-spanner to remove the chuck. Now I'm curious to see who is causing this runout. If the spindle is fine I'll replace the chuck. Anyway this one feels very gritty and usually it requires both hands to turn the key.

Then I think it is time to try to remove the chuck to see where is the problem.

One more thing, if I push the chuck I can make the indicator to deviate by up to 0.025mm at 2cm from the chuck. Is this normal or maybe the bearings are worn out?

I didn't noticed it. I just tried now to use that socket hole. I got repeatedly 0.2mm runout! With the other socket holes the runout was again bellow 0.150mm. So maybe that mark means to don't use it

That is a better idea than trying to grind the jaws or the hex! I think I'll try it. Meanwhile I made some measurements with a test bar:

The maximum runout is 0.130mm at 20mm away from the chuck. I repeated the measurements from the video for different levels of forced applied to the chuck wrench. In any case the runout didn't exceeded 0.150mm at maximum distance from the chuck. It is interesting that for a moderate force used to close the chuck the runout is bellow 0.08mm. How good are these numbers?

Edited By Sonic Escape on 08/08/2023 11:16:35

I looking for a way avoid to loose concentricity every time I remove the workpiece from the chuck. Also I want to avoid to remove the 3-jaw chuck. It is fine if I find a solution for diameters up to 20-30mm. My first idea is to hold this kind of ER collet in the chuck:

There are two options I could think of. I could try to scrap the faces of the hexagonal part until there is no runout. And next time put the ER holder in exactly the same position. I suppose that this will take a lot of time.

The second option is to make an ID grinder for the tool post and to cut a little the jaws while they are opened exactly at the same diameter as that hexagonal part. And of course the jaws should apply pressure on something during grinding.

Does any of these two ideas have any chance to work? Because if not then I have more 

Edited By Sonic Escape on 07/08/2023 16:29:32

I did the same. But lately I did a lot of turning between centers. I had to remove the workpiece to check the live center height.

I made a plastic sleeve. In this way I can use longer bars that extend on the left side of the lathe. So less waste of material.

I'm not sure if this even deserves a separate thread. For a long time I wanted to make a height gauge. Without one it was time consuming to adjust every time the tool height. I kept putting it off because it didn't looked like a very interesting project. But it seems that it's not always bad to keep putting things off. Today it occurred to me to do this:

It took only a few minutes to use the vise to insert a piece of soft aluminum together with a depth gauge into that knob. It is very solid and it works well. The two horizontal arms are at exactly the same height. Being lazy can take you to the simplest solution

Edited By Sonic Escape on 06/08/2023 20:31:54

3 months ago I used a brazed parting tool on stainless steel. It worked fine. Even considering that the workpiece was not supported with a live center. But it is about 5mm wide so it is wasting material. Also later I was not able to duplicate the operation. On the same type of material.

Edited By Sonic Escape on 06/08/2023 20:06:23

My lathe is a medium size industrial machine. 750mm between centers, 140mm chuck, 800kg

The center section was cut with a hacksaw?

Thank you for all replies. They were very useful. I didn't knew about RDG tools, there are a lot of interesting stuff there. I think I'll try a T shaped HSS blade. For parting I don't like to make deep cuts required for carbide tools.

On my lathe I can't use a rear tool post. But I can reverse the motor direction. So if I mount the tool upside down it should be the same thing.

I remembered that I have this tool (20x20mm). Does it worth the effort to try to make a parting tool from it? This would mean to decrease the width of the top part to 2-3mm. A lot of grinding.

Edited By Sonic Escape on 04/08/2023 15:51:45

I had a look on other parting tools on that site, Chronos, and I found this model:

It is not a HSS blade type but unlike other models it doesn't hang outside the tool post. Maybe this helps.

Edited By Sonic Escape on 03/08/2023 16:27:56

That is interesting! I suppose it cuts more efficient than a plain blade.

I'm looking for a good parting tool, preferably with a HSS blade. Something like this:

It should cut to a depth of at least 10mm. My tool post can hold tools up to 23mm tall. So I would avoid those 10mm tools that seems to be so common.

Anybody tried this kind of parting tools? I don't see how that insert can stay there ...

Edited By Sonic Escape on 03/08/2023 15:24:10

Today for the first time made something useful on the lathe. A friend needed 4 stainless steel spacers for a packing machine that he is fixing. It took me almost 3 hours. I think I would starve to death if I'll have to make a living from my lathe skills.

I bought a 6.5mm DeWalt Extreme Cobalt drill for the holes. This drill is worth the money. After drilling ~170mm of stainless steel in total the cutting edge is still very sharp! It has also a triangular section on the tail so it doesn't slip in the chuck. I don't know why they don't make all drilling bits in this way.

This was a good time to use also my latest finding on the Sunday flea market, a huge Jacobs chuck. This relict has stamped on it Carpati (Carpathian). So it is an old Romanian model. I suppose this is the largest chuck made for MT3. It looks like it was used a lot but it opens/close smooth and the jaws are in very good condition. It is heavy and I like it a lot.

After every few mm I removed the drilling bit and add more paste and remove the swarf. There was a lot of swarf compressed inside. I don't know if it is ok to make such a deep the hole in one single drill.

In exchange I got an 8mm H7 reamer. It doesn't have a square tail but it still useful.

I think that is a cold saw. It cuts at speeds as low as 20-80 rpm.

Why there is a different blade for stainless steel? I want to cut both stainless and mild steel. But I don't want to buy both  Does it really matter?

Edited By Sonic Escape on 31/07/2023 17:00:02

I want to be able to cut mild steel plates up to 10mm thick. Or square bars up to 20x20mm. Speed is adjustable up to 1400rpm.

Edited By Sonic Escape on 31/07/2023 14:44:14

I want to buy a large TCT blade to cut steel. I found the Evolution brand and I wonder if it is any good. There are many positive reviews but also cases when people complain that after a few cuts the blade didn't work anymore. Or are there better alternatives?