Mbfrontier's Logan 200 Rehab

Well, just as my spindle bearings arrived another project took over but I managed to get the bearings installed the day after they arrived. After installation I was still getting chatter but not as bad. After changing the carbide insert on my tool holder and sharpening the high speed steel turning bit life is good.

Here is a picture of a mild steel rod I turned with the larger two diameters on the left showing the chatter I was getting before the bearing change and the smallest diameter on the right after the bearings were changed and a new carbide insert on the tool holder.


Here is a picture of the mild steel bar I was turning today after a finish cut with the carbide bit.


Here is a picture of the mild steel bar I was turning today after a finish cut with the high speed steel bit.


In conclusion, I may have been able to get acceptable results without purchasing new bearings but now I'll never know. I can positively say the lathe runs significantly more quiet than it did with the old bearings after the rehab. Therefore, it must be a contribution to a smoother and chatter-free cut. That's my story and I'm sticking to it.

That's it for now.

I agree with your final assessment. Not knowing what you were cutting with, I was tempted to offer that you might want to visit your cutting tool geometry before spending all that bearing money. Carbides are no free lunch either on small machines, and can often be a problem themselves unless one has the right tool architecture. As most carbide tooling is made for negative rake, high feed & speed, they can be pretty marginal on our little buggers. The key was that it also ran quieter. That is a hard thing to determine unless you know from experience how quiet they SHOULD be, but to notice a large improvement there proves your surmise was correct.

Congratulations Mike. Your surface finish looks VERY nice!

Carbide inserts have a nice radius on the point of the tool, which can be problematic with light duty machines. For larger, more rigid machines, this contributes to a nice surface finish. But for these smaller ones, it can be a bear for chatter. I think you are going to be much happier with high speed steel, since you can control and experiment with tool geometry.

With carbide, you will want to turn up the rpm pretty high - maybe higher than you may think, and the chips should come off the part very hot (blue). If your test didn't produce this, you may want to do more experimenting.

I agree though, if you notice a difference in how quiet the lathe is, the new bearings are a good thing!

You did a beautiful job on the machine. It's really inspiring some of us slower folks.
Glad to see it cut so smooth/clean.
If you get a chance, keep us appraised as to how that chain wax work out on the gears.

Thanks for the positive replies.

The chain wax has been working fine. I did add a few drops of Bel-Ray synthetic gear lube to make sure there is lube available to the gear teeth if and when the wax wears off. I like the chain wax for its' anti-rust properties as well as lubrication. I had read about others that feel it makes the gears run more quiet but it seems that the gear lash has a greater effect on how loud or quiet my gears run. I am planning on touching up the lube on the teeth of the gears periodically with the Bel-Ray synthetic gear lube. I will revisit this subject again after I have run the lathe for a longer period.

Currently, I am trying to improve my HSS tool bit grinding skills. It reminds me of learning to TIG weld. The only way you learn is to get in there and learn from your mistakes along the way. I have had some success with grinding and honing right hand turning bits that produce nice finishes on mild steel as shown in my previous picture. Luckily, HSS bits are still relatively inexpensive so I can ruin as many as I want without a major financial impact.

That's it for now.

Mike,

I'm glad to hear you are experimenting with grinding HSS tool bits. I believe this is something missing in the education of hobby machinists (and maybe even machinists in general). With all the different carbide tools available, it seems they are used for everything. Back in the day, the first thing an apprentice machinist had to do was grind up a few tools to use. I believe it helps give a sense of what is really happening at the cutting edge. This is a very useful basic understanding.

Another thing you may want to try is, instead of using 1018 mild steel, get 12L14 ledloy. It machines so much nicer than 1018 and it is easier to get a good surface finish. I have switched to 12L14 and won't go back.

Hey, thanks Aerohawk.

I'm not sure if my steel supplier has anything other than 1018 mild steel. I recently purchased 4 "drops" of 1018 round bar to begin testing and adjusting with when I figured I was nearing completion on my lathe before I went the extra step with the two spindle bearings. I'll have to check and see what else they have available the next time I'm there.

Right on Aerohawk;

Tool bit geo is critical. I've learned that much. HSS is the way to go on these machines in most cases. Carbide is misapplied in many instances, and can lead to frustration. 12L-14 - and a lot of others - definitely turns better than 1018. Tom Griffin on YouTube does a nice job showing the grinding process in his videos. They are worth a close look, especially for we visual learners. Almost like having a mentor standing over your shoulder.

After watching his videos, I've been using Tom's drawings for turning and facing tools to reference the geometry when I'm grinding. They have been very helpful. They are available at tomstechniques.com.

Here's a picture of the first actual part for my lathe that I made since the lathe has been completed. It's the rear spindle collar that I'll be using on a future lathe upgrade. It's nice to finally be able to make parts.


That's it for now.