PTS Flowbench Forum

Daniel perfect

Thanks

Some news from the turning scene.

My first lathe experiences were quite disappointing. Even though I rebuild the whole lathe after cleaning and reoiling, I had a rough surface:


Since I have used a very cheap beginners set of carbite turning tools and I thought it could be caused by them, so I ordered some additional turnings tools. In the meanwhile I found a nice mailing list, where the users told me that this could be a still nonstable connection somewhere between the tool post and the several slides. I moved all parts by hand, but didn't see or feel anything, so I turned the turning tool backward into the tool post and moved it against the material in the chuck. After pushing a bit, I found a very little play in the top slider. I adjusted it and tried new round bars of brass and aluminum:


The difference between the first tries (middle) is significant. I am very happy to have a working lathe

In the meanwhile I also received some new indexable turning tools and a very cheap QCTP (Quick Change Tool Post) with 8 exchange holders.




I know there are much better QCTP sets on the market, but I had to watch my budget and a hardware store was selling them for a very good price, so I catched the chance and bought two sets (1 Post with 4 holders per set).

The indexable turning tools are from Glanze (Indian made, but have good reviews for home lathe users) and Sandvik (bought used on ebay).

Now I can start to make my first parts ... and the first will be some pressure pick-ups which I missed ordering from bruce

Cheers,

Daniel

Did you use any cutting fluid when you turned the first piece?

Play with your speeds, feed and depth of cut on parts like that to get a feel for what they need to be for various materials. Some "cheap" material no matter what you do will give crappy surface finish.

Welcome to the machining world!

Brucepts wrote:Did you use any cutting fluid when you turned the first piece?

Play with your speeds, feed and depth of cut on parts like that to get a feel for what they need to be for various materials. Some "cheap" material no matter what you do will give crappy surface finish.

Welcome to the machining world!

Hi Bruce,

I didn't use cutting fluid on all three pieces, as I wanted to play around with the machine first to ensure that everything is working as expected. Then I will start improving the machine and adding cutting fluid support, larger fluid catch pan and so on.

The problems with the first surface was from the little play in the slides. No I am playing around with speeds and feeds and making a lot of chips

Cheers,

Daniel

Daniel,

Your first picture shows a lot of chatter as Bruce said this can be speeds feeds and cheep metal. I noticed two things one on your second picture your Part looks to be large showing that the tool bit was below the center line of the turning this should be set at center to slightly above center. Second you are using carbide insert tooling and this is even more sensitive to contact placement with respect to the centerline of the turning. I have found these types of tooling to perform best at very near center. The type of chatter is common with weak tool support and flex in the tooling but can be overcome by keeping the tool as close to the holder as possible, not over extending the compound and keeping your speed slow. Just remember that if you search the net for turning speeds for different materials you will find them to be fast as they are for the ideal conditions in a production environment and everything slows down from there as the equipment and tooling change. It looks to me from your brass and aluminum that you just need to get more familiar with your setup.

Best of luck

Rick

Hi Rick,

Thank you very much. I am currently learning and reading and learning to get more into metalworking.
As you can see: I just bought a QCTP set. This set allows me to adjust the height of the turning bits, which wasn't so nice with the standard Tool Post.

Now I can center them exactly, so I hope it will be a better surface than the both examples before.

By the way: What turning/drilling emulsion could I use which can be brushed on the piece ? I don't want to mess around with a whole cooling/drilling spray set.

Daniel

Daniel,

You need to be careful with this as many cutting oils and cooling solutions smoke and emit nasty fumes, and since this is upstairs in your living area it could cause some issues with your home life. You may find that vegetable based oils will suit your needs many such as safflower oil have a high smoke point like 400 + degF.

Rick

Hello Daniel, congratulations on your initiative to become a man Diy machine.
Firstly you have a problem of this structure of your machine, it was not made for this type of work that you show us. but for micro mechanics (light work).
but for sure you'll do everything you need to be careful and respecting the limits of your machine,for you to have better results and enjoy this great set of tools at hand you must do several experiments as has been said to you.
you should first do some tests on wood because it is less risky and cheaper. observation is that the wood you need high speed this will bring you more abilities to handle and then you worry about other material and finishes.
some tips, you must to completely eliminate the vibration of the tool to bore a hole in the center (use drill center) and always use the rotating tip, so you eliminate the great effort that your board needs to do to hold the piece and eliminate vibration,Evidence that this occurs and the deepest mark of the first tooth of bracket(sorry I not translate correct).
speaking on board do not open too fixição least two teeth left, because if they are not Chinese standard and has only hardened the material very prone annuity and break easily (already broke a set of tweezers)
the perfect hint of Rick and above 10mm is always good to get a little tool so you change the angle of attack of the cutting tools now.in case of cutting tool to separate the piece into two (bleed) from above the center (center line)
in your case and have two better tools to work, to give an initial roughing and finishing second, removing from below 0.50mm to have a good finish.
cutting fluid! in your case I think is better and cheaper and less dirty you use to spray with iron particles fuciona oil well (helps in cutting but not cool) improves the finish
in aluminum only use alcohol because it cools quickly and good finish (best tool for aluminum diamond excellent)
Cast iron does not require cooling only proper tool for this (rust quickly)

tips
The tool for focusing the use of cutting edge wheel.
always wear protective glasses mainly with non-ferrous material.
care in the winter with long sleeves (I have 38 points in the arm)

expensive than labor, for writing all this sorry for the mistakes! would be easier for me to make a screw with two threaded entries
I hope you enjoy these my words something

What you may also try is when you set your cutter height have it just slightly higher that the center of your piece you are cutting on. This helps me. I usually just take a small metal machinist rule and crank the cutter in, without it turning of course, to where it holds the machinist rule in between the cutter and the work piece. I raise the cutter until the top of the rule just ever so slightly tips in. That seems to work well for me. That seems to help cut off the metal instead of scrape it off.

John

Thank you very much for all the tips.

Today I made my first real piece. When I ordered stuff from bruce, I forgot to order pressure pickups. So I found my first project.

When I figured out the overall lenght of the pickup is larger than my hss boring bits. So I ordered some extra large hss boring bits to make the final pressure pickups for the flow bench.

So, here is just a prototype:




I turned down hexagonal brass bar to 8mm, bored a 3mm hole and cutted a M8 thread.
When the longer hss boring bits are in my hands, I will build similar pickups, but after the thread, there will be the connection for the tubing.

Cheers,

Daniel