Make Your Own ER11 Spindle

[bergerud]

There are three holes.

[ktjwilliams]

Hey Dan,,, How U been ?? I finally ordered an ER20,,, A lot of my favorite bits are 1/2 inch and I just can't find replacements for em in 1/4 inch.... My neighbor GAVE me a metal lathe.. Been practicing cutting various types of metal, very interesting trying to use this thing, lot different then my wood lathe,LOL.. But I have now figured out some of the quirks with this machine,,, Like having to center the cutting tool,, it scared the hell out of me the first time the work piece jump up on top of the cutter tool cause the tool wasn't centered.. lol... I mastered centering the work piece in the 4 jaw chuck, with a small piece of wood with a bearing mounted to it and a dial indicator.. Well I think I'm getting close to being ready to try cutting the ER20.. I bought from China cause as we all know they R not as hard as USA stuff.. When I get use to this thing, I'll order a couple of USA spindles ER11 and ER20... any advise ?? Oh,,I mounted a small paint brush to the machine, I keep it oiled and resting on the work piece while cutting.. works good keeping things lubed...

[bergerud]

I just got a US ER16M to try from Maritool. The ER16 goes up to 3/8. I only need up to 1/4 but I think the bigger collets hold the 1/4 shanks more accurately. The 1/4 collets on the ER11 are thin being on the upper limit of the capacity and so distort when tightened. Splitting hairs?

I hope you ordered the ER20M type chuck. The ER20A type has a big nut. Do not even try to turn the chuck by holding it in a lathe chuck. You may, after awhile, get the taper centered in the 4 jaw, but, you will not be able to get the axis of the collet taper and the axis of the lathe parallel. (We are working with 10 thousandths here) Use the stub method I described in the thread " ER Spindle Conversion - details" which has moved down a ways in the threads.

Another thing about the ER20 is that a lock pin might not be a good idea. The extra torque required to tighten it should probably should not be transferred to the carriage bearings.

Good luck, you may ruin the first one in the learning process. Anyway, I am glad someone is giving it a go. Funny that the two of us that have ER chucks seem to be the only ones excited about ER chucks.

There are a lot of people who read the posts but do not post themselves. If any of you out there have converted an ER chuck to the Carvewright, we would like to hear about it.

[gregsolano]

I like the idea and would purchase one if someone was selling it but I do not have a metal lathe and between buying a lathe and learning how to use it for just this one project it would not make sense. I do have the CT chuck and I am happy with it. If the person you talked to decides to start making and selling them then I would be interested in buying one.

[ktjwilliams]

Well Dan,, I ordered the "A" because I found one that had a thin shaft to begin with so it won't require a hole lot of cutting down... Guess I'll have to go find that old post on the conversion.. I don't fully understand what the heck UR talkin bout with stub method... I was just planning on using the 4 jaw chuck and the tail stock for support.. In any case,,, The "A" has to be better the QC LOL !!

[bergerud]

My first mistake was thinking that a precision ground China chuck is straight! The chucks from China are garbage as they stand. Both bearing journals have to be turned to make the thing straight. The stub method is as follows. You put an old bolt shank in your lathe chuck and turn it down to the size if a bit shank. This gives you a near prefect way to mount the collet chuck on the lathe. Since the bolt was just turned, it is as straight and true as your lathe can be. Now you attach the collet chuck to the stub as if it was a bit. You will be shocked at how the shank of the collet chuck wobbles. (The $50 US ones are a lot better.) But no matter since you are going to make it straight.... Go back and read that old post so you do not repeat my mistakes.

[Jeff_Birt]

The chucks from China are garbage as they stand.

There is a lot of high-quality stuff made in China but unless you are dealing with a known supplier most of what you get is poor quality. I submit for evidence: http://blog.jitbit.com/2011/04/chinese-magic-drive.html (in good humor). Once you turn the shank down the alignment between the taper and shank will be shot, and we won't even get into how accurately the taper was to begin with. Bergerud is correct, the money spent on a US make collet chuck is money well spent.

The 1/4 collets on the ER11 are thin being on the upper limit of the capacity and so distort when tightened. Splitting hairs?

Actually this is a really good point to bring up. Part of the problem could be the collets, cheaper collets are softer and will 'smush' (technical term). A problem many folks have with ER collets in general if over tightening them. If you over tighten the closing nut you will distort the nut and then every collet you use with that nut will be ruined eventually. This is the #1 killer of ER collets.

TIP: You want really short wrenches, for the mills I sell that use ER16 collets I supply them with two 6" long stamped steel wrenches (like bicycle wrenches). They are short enough that it is hard to get enough leverage on them to over-tighten the nut. Tighter is not better in this case, get yourself some short wrenches.

I cut a pair of the above wrenches out of 1/8" 6061 aluminum more than a year ago as a test. I wanted to see how much wear/rounding would occur on the wrenches with normal use (steel nut/aluminum wrench). They are still in great shape which shows how much torque really needs to be applied.

[bergerud]

We are talking about the $15 collet extension chucks on eBay. They seem to have a concentricity problem (axis of taper and of axis shank not parallel). I was told by a supplier " The shank is ground centreless and the taper is ground spinning the chuck held by the shank so it is nearly impossible not to make it concentric". Well, I guess the machine chuck which holds the collet chuck shank is not so true!

The beauty of this conversion process is that these problems can get fixed if you turn both bearing journals. The taper is the "face side" that you start with. Using a high quality collet, you hold the cheap collet chuck by the bit and turn it to be concentric. If done carefully, the cheap collet chuck can become as accurate as the high quality ones.

Somewhere, I saw collet nuts which had a bearing in them. The idea was that the bearing eliminated the torque on the collet due to friction when tightening. I suppose one would like an even shorter wrench for these.

[ktjwilliams]

Dan I read the details last nite and got the idea an understanding of Y to do it that way, Great idea,, At present I don't want to go buying $ 60 & $ 70 USA spindles yet.. I think the ones from China will cut much easier then the USA ones cause I don't believe they will be as hard.. Once I cut a couple and get it right then I will invest in a USA made one.. However the collets I use ARE NOT from china, Those ARE STRICTLY USA made.. I would not trust a china collet.. As far as tighting, I cannot twist or move the bit just by finger tighting.. So after finger tight I put the wrench on and give maybe a half turn.. No problems... At first I thought the bit would push in or come flyin out but, neither happened and it works well with that little tightening...

Kevin

[Dan-Woodman]

How will you put the square hole in the end to accept the flex shaft? I think they make square keyway cutters for that,but just wondering how you guys would deal with it.
later Daniel