Drilling Delrin fast

[Atlascycle]

How deep is the hole?

 

[Torque1st]

Hey, I try to think outside the box occasionally. I think I used a spade bit to drill some delrin but it has been a LOONNNGGGG time ago.

RE:

+1

That may be the best suggestion yet :D

Since just a couple of thousandths need to be removed from each side of the bit, a fine cut file could be used. Plus, with no flutes to clog, the Delrin chips & curls will come out of the hole easily.

 

[1917]

You might try setting your drill, endmill, reamer or whatever up in the toolpost. The carriage usually has more travel and can be moved in/out faster.
Maybe try a 7/16 two flute endmill. offset in the tool post just right to get the right i.d.

 

[sortafast]

You might try setting your drill, endmill, reamer or whatever up in the toolpost. The carriage usually has more travel and can be moved in/out faster.
Maybe try a 7/16 two flute endmill. offset in the tool post just right to get the right i.d.

thought about that, but set up time might be a bit of a beeyotch. Plus I would probably have to buy another tool post holder. Once set up though, it would be very fast as I wouldn't need to reset the tailstock after every part.

I might try the spade bit and see what happens. I just worry some about deflection since i have to go between 2-2.5" deep, which is right at the limit of the tail stock.

 

[Atlascycle]

If you cannot find the correct size drill then you might want to see if there are any tool sharpening companys around that can grind the drills to the size that you need and then grind the lands in to them for you, or just grind it under sized after leaving a small section to properly size the hole.

We have our end mills reground when they are dull and the grind the relief back in them be fore they send them to be recoated.

Jason

 

[Torque1st]

I might try the spade bit and see what happens. I just worry some about deflection since i have to go between 2-2.5" deep, which is right at the limit of the tail stock.

One of the advantages of drilling in a lathe is that the stock turns which tends to self center the drill.

 

[1917]

thought about that, but set up time might be a bit of a beeyotch. Plus I would probably have to buy another tool post holder. Once set up though, it would be very fast as I wouldn't need to reset the tailstock after every part.

I might try the spade bit and see what happens. I just worry some about deflection since i have to go between 2-2.5" deep, which is right at the limit of the tail stock.

Not sure how it would work with your lathe but you could make a toolpost by mounting a block of steel. Drill and ream it to the size you need using the drill and reamer in the chuck. Center height would be right on. Add a set screw and grind a small flat on your drill/reamer. A lathe can make a nice horizontal mill for some jobs.

 

[precisionworks]

you could make a toolpost by mounting a block of steel. Drill and ream it to the size you need using the drill and reamer in the chuck.

+1

That's a great idea ... there are three or four of these dedicated posts on the shelf by the lathe for jobs I've run in the past.

It's really simple to make one. Buy a length of hot rolled steel square stock - 3"x3" works well for small to medium sized drills. The stock can be center drilled in the lathe chuck, but that means less than half is available to hold the tool ... or two mounting holes can be drilled in the mill (one near each edge) which means the post cannot rotate. Much better as the drill gets larger.

I've also welded up a stack of square plates when a larger post was needed for a boring bar holder:

The goal in making this TP was to hold the 1.75" Pafana (Polish) boring bar. That bar was purchased specifically to bore a ... DELRIN job :D The bore depth on the delrin rod stock was too much for little 1" bar, but the 1.75" bar does a nice job.

The second objective of this TP project was to make it as butt ugly as possible, and all my friends agree that it rivals any TP made by most third world countries :nana::eeew::crackup:

 

[HarryN]

One other option, is to get it done on the right tool. (most likely a mill or drill press). Since you don't have room yourself, consider the impact of jobbing out that specific hole in a batch of 50 - 100 to someone else. If this lets you accomplish more of the "other aspects" of the work, and you can at least break even on the arrangement, why not ?

I have done just enough machining to know almost nothing, but I don't expect a spade bit to be stiff enough for the job of going 1/2 in dia x 2.5 in deep. Maybe a bottom cutting end mill with some chip relief ?