I've been reading and googling about collets for my 10f.
Seems the original ones are a 3AT, which I take to mean taper to fit the spindle/headstock. Those seem to be very expensive though.
But it seems people use all different types. I've seen 3c, er11, er32, er42 and all other sorts of numbers.
I'm just looking for something that will bolt up to my 10f, hold end mills for my (new to me) milling attachment and further down the road allow me to explore the other uses collets are good for (still learning very basic stuff).
I'd also like to not spend the bank on them. I see sets on eBay anywhere from 35 bucks and up, but I don't want to buy crap. The buy it now auctions with cheap or free shipping are also very attractive as shipping to Canada usually cost as much (or more) than the item.
I'm also not adverse to building some parts of a collet system myself as long as its not too complex (still new to machining) and it would be good practice.
So, can anyone clear up which of those collet numbers would work in my atlas with the least amount of trouble?
I'm also not clear on the whole drawbar thing. I think I understand the basic principle, which is a bar that pulls the collet into a taper in order to clamp the work. I would prefer not to use a drawbar (because of the atlas change gear cover) unless that's a more reliable system than a chuck with a ring.
Any help appreciated. I'm pretty turned around in my head from all the info.
Oh yeah, please keep it simple. I'm on info overload right now....
I have an old Atlas lathe model 36H that came with 3AT collets. I will try to attach photos of the collets and drawbar. On my lathe I have a MT3 (Morse taper #3) in the headstock, and it requires an adapter to accept the 3AT collets. There is also another ring that should be screwed onto the threaded spindle before installing the adapter to make it easy to remove the adapter by just unscrewing the ring forcing the adapter out. The drawbar fits through the headstock and the change gear cover without any problem, but it must be removed to open the cover of course; simply loosen from the collet and slide it out.
One issue with the 3AT collets is they can only accept up to 1/2 inch diameter maximum stock. I wanted to be able to handle larger material, so I built my own 5C collet adapter. I found a bar of suitable diameter and chucked it up in my 3 jaw chuck and bored a hole in one end and threaded it to screw onto the headstock (1 1/2-8 thread if I remember correctly). This needs to fit snugly and needs a flat face to be able to remove and install with minimum run-out when completed. You might want to cut a male thread in some scrap bar stock that is a nice snug fit in a chuck to use as a go-no go gauge for the inside thread first. Cut the face and the thread before removing from the chuck if possible for best accuracy. Then I screwed the partially finished adapter onto the headstock and bored the other end to accept a 5C collet, and cut a fine pitch outside thread and made a mating cap to push the 5C collet into the adapter. I drilled holes in the adapter and the cap to accept a spanner wrench for tightening and loosening of both the adapter and the cap. I also cut a notch in the side of the adapter to allow inserting a screwdriver to push the collet out if needed, and added a couple of set screws to mate with the slot in the collet to prevent it from turning in the adapter. I used a stainless steel bar I had on hand, but you might want to obtain some 12L14 bar stock that is easier to machine for this project (
www.speedymetals.com). You can get a 6 inch length of 2 inch dia for about $10 at speedy metals. The cap can be the same material if you want. You can find the dimensions for diameter, length, and taper of the 5C collets online. Cutting the taper inside the adapter can be tricky if you do not have a taper attachment for your lathe. I just set the angle for my compound close to the value and made a cut on a scrap bar stock to measure the taper. I used a dial indicator to get the diameter change and measure at two points a few inches apart to get the taper. Then I tweaked the compound and repeated until I was at the right angle. You could also install a 5C collet in your 3 jaw chuck and mount the dial indicator on your compound and then tweak the compound angle until it matched the collet taper.
I purchased an assortment of 5C collets on E-bay and now have up to 1 1/8 inch diameter capability. Of course if the bar you want to hold is over about 3/4 inch, it will not fit through your headstock, so you are limited on length of material. This has worked very well for me for the past 25 years or so.
Another option is to purchase a set of ER collets and a matching collet holder on E-bay. You can get a MT3 collet holder in up to ER-32 collet size which will accept up to 3/4 inch diameter collets. The holder might cost $20 from China, and a set of 19 collets will cost about $33-$75 if you can find them in stock. The 19 piece set will handle all sizes from 2mm to 20mm. This is definitely easier if you can live with the size range. You still might want to fabricate the ring for easy removal of the MT3 collet holder.
If you have questions or need dimensions, send a request.
