My first lathe arrived today

[emtor]

Hi Emtor,

Yes that is more like it ! I use very few carbide tools, preferring HSS. But that finish is very good.

I'm happy with the finish, but I do have quite an amount of chatter.
No chatter while facing, chatter while turning along the axis of the workpiece, and lots of chatter when chamfering.
Last night I got long spirally strings of chips,-up to 3-4 feet long, and then I noticed that one inch was yellow,-one inch blue, then one inch yellow and so forth. Equal and consistent distances between the yellow and blue.
I'm thinking,-does the workpiece move back and forth into the cutting tool while rotating? -Or maybe it's just tool / toolpost / cross-slide etc. chatter.
Tomorrow I'll check wether the chuck is consentric or not.
When I got the lathe the first thing I did was taking the three jaw chuck apart, cleaned it and oiled it.
When inserting the jaws I started with number one into the correct slot, rotated anti-clockwise until the jaw snapped into place and pushed the other two into place also. I noticed that number three didn't move inwards while turning the chuck key clockwise. I had to fiddle a bit with it before it fell into place. It seems (judging by eye) like all jaws are correctly centered, but number three did have problems mating with the scroll.
I have three spare jaws and I'll try those to see if I encounter the same problem. If no problems then it was jaw number three who acted up,-if the same problem occurs with the spare jaws then I may have a problem with the scroll.
I'll also insert the live center, put a piece of rod from a printer into the chuck and see if the face of the rod rotates evenly around the live center. (No measuring devices as of yet).
I won't give up until these problems are fixed, and . . . I haven't had so much fun for years,-should have bought the lathe years ago.

 

[BaronJ]

Hi Emtor,

I think as an initial buy, I would get a dial gauge, at least 0.001" (1 thou ) per division, or metric 0.01 mm (1.27 thou ) per division, and a cheap mag base. You will need to buy or make some clamps to support the gauge.

Actually they are easy to make, particularly in aluminum. Drawing below.
A bit of square bar, drilled to hold the gauge stem, usually 8 mm diameter and use 8 mm rod as needed. Some gauges are a slightly different diameter stem. So drill to suit.

Cross drill a hole at each end, and thread to fit a clamp screw, put a saw cut through from the end into the 8 mm hole.
The idea is to be able to tighten the screw to clamp the gauge stem, do the same at the other end to clamp the 8 mm rod. Make as many as you need.

The holes marked 3 mm need to be drilled tapping size. The holes marked 8 mm are simply drilled.
One end is 90 degrees to the other. When all the holes are done simply slit with a saw from the end into the edge of the 8 mm hole.
Drill one half of the 3 mm hole to clear the screw threads.

 

[emtor]

Ta-taaaaa . . . . I solved it!
Last night I noticed that the long strings of chips were blue-yellow-blue-yellow etc.
Thanks to my experience in making knives and hardening and tempering steel I knew that the chips were subjected to varying heat caused by a varying load. I knew that this was caused by runout. I took out the jaws and reinstalled them making sure that jaw number three followed the other two.
Then I turned the workpiece and when finished it suddenly dawned on me that what I had heard was only the motor and gears.
I took another pass and there was no chatter. Took a deeper pass and no chatter. Then I let the workpiece stick out a good way from the chuck and took
an even deeper pass, this time the tool was eating steel . . . still no chatter.

The problem was runout from misaligned jaws.
The lathe feels rock solid now and is a joy to work with.

 

[BaronJ]

Hi Emtor,

That's great news to hear ! I'm glad that its problem solved.

However I would still invest in a dial gauge.

 

[emtor]

I did order a dial gauge today, HSS cutter set, and center drills plus a few other items.

After some turning the 1" diameter workpiece got way too hot to hold in my hand and the shavings were almost black and crispy.
I must have taken quite deep cuts. This lathe seems to be a sturdy and solid machine despite being a "mini lathe".

 

[BaronJ]

Hi Emtor,

It is surprising just how big a cut you can take. But I wouldn't do it too often.
Fine on the parts that you have ordered. Rather than the cutter set, I would have bought some HSS tool steel blanks and ground my own. You have more control over the shape. But it does mean that you need a grinder... More tools.

Forgot to add, watch the temperature if you are aiming for a given size !

 

[silence dogood]

Emtor. When I took my lathe apart the first time, I found some flashing and paint over spray. After cleaning it up, one place that made a big difference were the half nuts. You also can't trust the Chinese nuts and screws. They seem to be too soft. I replace many of those with better quality.

 

[emtor]

BaronJ --> I won't be taking as big cuts in the future. I just had to see how much it would take to introduce chatter.
Turned out it took quite a bit.
I did order HSS blanks . . . and I've already bought a grinder
The set I ordered are solid HSS steel, not inserts that are either brazed or replacable.
I've heard the same regarding chinese nuts and bolts . . . soft.
I've cleaned out the room now . . . soon time to take the lathe apart. I'll inspect the half nuts.
I had to replace the belt. It was a real pain to take it off and put it on the other pairs of pulleys.
The new belt is a fan belt for old cars and is easy to come by. 100 mm longer than the original and much easier to change speeds now.
The lathe has a belt tensioner so the extra length is of no concern.

You're right about tolerances when hot or cold. A part turned to dimension will have a lot of play inside a hole when cooled off.

Well,-it's a chinese lathe, and although among the better ones it's not a Swiss clockmaker's lathe, so it will need some modifications here and there.

 

[BaronJ]

Hi Emtor,

Fine about the belt, on my Myford its a right royal pain to replace it. It seems that most people go for link belts !

Sounds like you have everything in hand

 

[emtor]

Hi Emtor,

Fine about the belt, on my Myford its a right royal pain to replace it. It seems that most people go for link belts !

Sounds like you have everything in hand

The original belt was so short that to get it off the pulley took a screwdriver and loads of prying and bending.
Neither the belt nor the pulleys would have lasted very long doing that. The new belt could have been a tiny bit longer but this was the best I could find at the car parts store.

Went up early this morning and mixed some lapping compound, 220 and 600 grit. The gib for the compound slide looked like it had been machined with the help of a lawn mower. Now it's back in place and it moves quite a bit smoother, and adjusting it rock solid takes less force on the set screws now.
Also the annoying binding of the wheel has improved. Next up is the cross slide. -Lapping is extremely boring BTW.

Yes, it seems like I've got everything in hand.