Making my first pen...

[workinforwood]

I have so many questions, although many of them I don't know the question yet. I figure, I'll keep my questions and answers in one spot if ya'll don't mind, and hopefully you guys will help guide me on my way. I have a vision and sort of a plan, I am just unsure how I get there.

Today, I have to call it quits in the shop to spend time with other things and family and have to work tommorrow, but here is where I am right now. I am truing a rod of aluminum and taking it down to the size I want the OD of the thread to be. The rod is easily 30-40% larger than it needs to be, and I do have smaller ones, but I want to use this larger rod to give me a feel for the machine and the sizing process..It's not like the rod is big money. And I'm using aluminum for it's ease of machining for my first pen. The questions though...well, I don't know that this bit I am using is the best choice for this job and if it is a good bit, I don't know what the angle should be. The rod is running about 8" long between the bed. The more I angle the bit so the point does more of the cutting, the rougher or deeper the grooves are in the rod as the machine travels across. With the point being agressively angled, when I am close to the middle of the rods length, it digs a bit extra so now the rod will not be straight across. In the picture, the bit is only at about a 1 degree angle, it may look like it's flat across, but it is only close to flat across and the cut is a bit smoother and in the center of the rod it cuts the same as anywhere else, nice and even, yet it still does have some grooving marks all the way across. Right bit, wrong bit, wrong angles, grooves are normal or should it be smooth..these are the questions I have and the rod isn't even to the right OD yet!

 

[Wild Turkey]

Jeff,

I am not a machine operator, but did work on CNC equipment for 20 years. Here goes what I do know. Speed, fast as you can, take very light cuts, and use a round nose cutting tool. The aluminum is soft compared to other materials and will flex if too much pressure is placed on it while turning. The type of cutting tool will determine what kind of finish you will get on the rod you are turning. Use a slow feed rate with all of the above and you should get a straight cut. Hopefully your travel of tool is even with the material you are cutting as well. Many factors to consider. There are guys out there much more knowledge than I have and maybe they can come with other answers as well.

 

[Texatdurango]

Jeff, Looking at the photo it looks like the cutter holder is on the right side of the tool post. I don't know whether it makes any difference or not but I have always seen the cutter to the left of the tool post. Also, I would not cut with the flat side of a bit like the one shown above, I would use a different holder so that one of the three tips was doing the cutting rather than a flat section of the tip.

I found a place last year called Swarfrat Enterprises http://swarfrat.com/. I purchased several of their DVD's and found them to very helpful with starting to use my metal lathe. In particular,"Mini machines 101: Cutting V-form threads on the mini lathe" and "Mini Machines 101: Lathe Fundamentals and Basic turning" were very helpful.

 

[Paul in OKC]

Ok, see if this makes sense. I would put the tool post 'square' with the axis of the lathe, and mount your tool in a holder on the left side. That tool is basically designed to cut with the 'left' side of the insert at or near 90 degrees perpindicular to the work piece. Work with as short a piece as needed. The closer you get to size, take smaller cuts. Thought at times a big cut right down to size will keep chatter down. Slow the feed rate down.
What kind of lathe do you have?

 

[Mike of the North]

I don't have time do a lot of typing so look at these web sites for help.
http://www.archive.org/details/textbookofadvanc00smituoft
http://bbssystem.com/viewtopic.php?t=89
http://techtv.mit.edu/videos/144-machine-shop-8
http://www.wewilliams.net/SBLibrary.htm

 

[workinforwood]

My lathe is 12x30 and yes, the cutter is mounted to the front and right side of the post, kinda on an angle like that so as to spear the metal.:biggrin: I will change to the left and use mostly just the point of the cutter for the next pass then. I learn best through talking with people and experimenting. I don't seem to learn very well through books and video's:bulgy-eyes: and I do have some of those. I do pick up fast, I just make mistakes, discuss what I did and that's how I know what to do. It's just how my brain works I guess. When I see Steve post a pic and talk a bit about what he did, it makes the most sense to me that way. I'm a left brainer!

 

[mredburn]

Aluminum bieng soft will grab the cutter if you are to aggresive with your cuts, The tool on the right side or left wont matter other than working close to your tailstock or headstock the crossslide could get in the way,or your tool holder will hit the chuck before you get the stock turned all the way up by the head stock. Have you checked to make sure your tool is even with the axis of your stock? if your above or below this it will effect your cutting. The easiest way to check is with a 6inch machinist ruler, with the lathe off run the tool point up to the stock and lightly pinch the ruler between the tool point and the stock. it should be perpendicular to the stock. If it leans in at the top your to high if it leans towards you or in at the bottom its to low.

 

[Mike of the North]

If you down load this http://bbssystem.com/viewtopic.php?t=89 and go to page 10 it shows the angle of the cutter to the work piece for roughing and finishing, if you lived closer I could show you how in a few minutes, be careful you can hurt your self quick if it does not feel right step back and think about it for a minute. You may want to check and see if any of the local schools offer machining classes, a few minutes with a high school machine shop teacher would teach you the basics.