Machining Delrin Round Stock?

I have machined many projects from delrin rod.
It's one of the best machining materials i have run across.
It's very easy to work, and is very useful for low speed/moderate load bushings and thrust washers.
It's very forgiving for first timers and is a great practice medium due to it's relatively low cost and ease of access

Steps should be taken to avoid overheating delrin as it has a relatively low melting point .

I have used carbide , HSS, and carbon steel tooling to work it with great success, it may just be my favorite material to machine!
 
Sorry Bill, you're right.

Tom, you raised a good point, one that was alluded to earlier in this thread. Proper work support is critical when working with Delrin because it will push away from the cutter as diameters drop off. Working with thin stuff caused me to look hard at tool geometry and it helps but we should always work close to the chuck when possible or use a live center or follow rest when we can't. In Jim's original post, his work was larger at the tail end and this is likely due to the part deflecting away from the cutter at the unsupported end; a live center or follow rest would help reduce that tendency.

Making big, short stuff with Delrin - a joy! Making small, thin stuff with a consistent diameter and nice finishes - not so easy! Delrin is a good teacher.
 
I machine a lot of Delrin. The work is flexing, further and further the further it is from the chuck. As said metal will do this too. Without knowing diameter and length it is hard to recommend a solution - but you CAN make very light cuts on Delrin. I have had no trouble with melting, from extremely heavy roughing cuts to very light spring passes for .001". Unless you're up at 4" diameter or more, use the highest speed you have. I use the triangular replaceable (CCMT? i forget) carbide bits for this and almost everything else. Stop. Measure. Cut. Remeasure. If the part has high length to diameter you may have to use some other method to "even out" the diameter along the length. But make sure you plan to approach finished diameter with at least 3 light cuts (under .010) to minimize the effect of deflection.

A follow rest may help too.
 
I machine Acetal/Delrin rod all the time, both using lathe and bridgeport. One of my cases is made from acetal that I pot my electronics in. I get excellent dimensional stability using HSS tooling. I always take a very light final cut to achieve an excellent finish.

I typically turn it around 280 RPM and have no issues with melting, even when hogging out with a boring bar with carbon inserts. Not knowing your complete specs. (I turn 1.75" Acetal rod at .7" length), but at 1/4" rod, I would use a 5C collet to hold the work. At that diameter, you can hardly go any length out of the chuck without tailstock, follower, and/or steadiest without flexing become a major issue. Need sharp tool and take light cuts.

Since I have a slow spindle (700 RPM max) old lathe, I use a lot of HSS tooling. I stopped grinding HSS unless I need a special form. Instead I use Arthur Warner Co. tooling/inserts. Once there is any wear on the insert, you just simply hone the top side and you are good to go. A whole lot cheaper than carbon insets and cuts better on my lathe. Puts a nice finish on the acetal.
 
cazclocker said:
I have found this thread very interesting too. I have a small project coming up that will require me to create a small push-handle for the end of a small shaft, out of Delrin. One question as another of the beginners here, is what is a Swiss-type lathe? What are the defining characteristics of it?
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A Swiss lathe has a moving head stock that does the work of a conventional lathe carriage, the work is held in the head stock by what ever method available, chuck, collet, etc.
The work passes through a bushing that rotates at the same speed as the spindle, the turning tools are located at the bushing nose where they move in the X axis, the moving head stock moves the stock in the Z axis when being turned. Such lathes require accurate stock to begin with and are often very limited in the length of cut. They are not however strictly CNC machines, Swiss style lathes have been used for precision work for a very long time, they are also not very versatile for general lathe work.
 
chips&more said:
I’m reading that a Swiss lathe is better at machining Derlin? Maybe yes, maybe no.
Click to expand...

A Swiss style lathe is a different method of doing the same thing that any other lathe does, the method employed is simply well suited to long L/D ratios. They have many requirements and limitations that make them unsuitable for general lathe work and most old manual Swiss lathes are very small indeed.
 
High side rake and relief angle HSS tool very sharp finished in a oil stone.
Big round tip to good finish.

But, for 1/4" material, you can't go far from chuck even with everything right.

 
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