That's funny. I get the impression you missed the point of why you would. I will point out one more time that the adapter and centers I photographed are all FACTORY products. The small end is also the end that goes in to the FACTORY spindle adapter. Have a good day.

Bill in OKC 

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better

On Saturday, June 4, 2022, 11:43:20 PM CDT, rlm_mcv via groups.io <rlm_mcv@...> wrote:

Sorry but you have missed the reasons why normally one would not make the adapter sleeve fit the small end of a Morse Taper as you previously suggested.  I am not interested in going out on a new tangent topic. Have a good day.

On Saturday, June 4, 2022 at 11:29:03 PM CDT, Bill in OKC too via groups.io <wmrmeyers@...> wrote:

And sometimes you need more bearing area to hold your piece between centers to work it. Larger center with a deeper center hole from a larger center drill will give you that. If you need the smaller center, use a different spindle adapter that takes smaller centers. Let's you use a smaller center drill, too. 

And if you need a full size center to the size of the spindle taper, they make MT5 spindle centers, tough a 9" SB won't need them. Nory 10L. But a 15" or larger SB (or other brand lathe) might.

Depends on what you need, and what you have. More options gives you more versatility, most of the time. And there are ways to give a dog driver more reach. Zillions of old books at archive.org if you want to read about it. 

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better

On Saturday, June 4, 2022, 07:48:29 PM CDT, rlm_mcv via groups.io <rlm_mcv@...> wrote:

Bill

You can hold a rotating object better with 2 hands rather than one.  The more surface contact offered by boring to the larger diameter of the sleeve offers the same principle of griping power.  Sometimes rather than a center you could be using a cutting tool in the taper that requires gripping power.  Examples would be boring something attached to the cross slide or using as a drill press against tail stock.

Another issue was sticking out to far using the small diameter.  Another user pointed out that if your out to far dogs dont reach.  Using your body again as an example you have less control holding something at arms length than you do close to your body.  Same with the lathe there is more control and accuracy closer to the spindle bearing.

The 3rd reason for wanting the shorter configuration is maximizing the length of material that will fit in the lathe.

I might want a long center if I was leaving my chuck on for some reason but otherwise I would probably want something short for the above mentioned reasons.

On Saturday, June 4, 2022 at 07:51:59 AM CDT, Bill in OKC too via groups.io <wmrmeyers@...> wrote:

Not saying you shouldn't, but all of these items are factory stock. None of it is home-made. Unless you make all your own, this is about what you're going to get. Both of the ones in the photo I attached earlier are factory-made carbide-tipped centers, and both of mine need reground. I hope someday to either find or build a decent toolpost grinder so I can true them.  I do have a couple of new centers. There is also a standard for stub centers, but I didn't actually look at it, and haven't actually seen any IRL or online. 

Except that the 7x mini-lathes use a shortened MT2 tailstock center. Don't know if they conform to the standard, as I traded mine off for a couple of Unimats a while back. 

Bill in OKC 

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better

On Thursday, June 2, 2022, 12:33:27 PM CDT, rlm_mcv via groups.io <rlm_mcv@...> wrote:

I prefer to use the largest diameter possible to have the most grip in a taper.  I also prefer to keep things as close as possible to the spindle (least overhang), to reduce stress and amplification of a mounting run out error.  The added benefit is it gives you the greatest distance between centers too.  Your preferences and or reasons might differ from mine.  Different applications can justify different setups.

On Thursday, June 2, 2022, 09:39:07 AM CDT, Bill in OKC too via groups.io <wmrmeyers@...> wrote:

Just sent the photo. It should make things clear. The adapter barely protrudes from the spindle. Mine is 3.25" long. The Morse taper sockets are 3-7/8" & 4-1/8" long according to the table I am looking at. Shank lengths are 3-7/8 & 4-7/8, and my #3 center is 5.1", and the #4 center is 6" long. The adapter is only 3-1/4 " in length, so there is a fair amount of protrusion. Another photo attached, and remember that the spindle adapter has a bit of protrusion, itself. About 1/8" on mine. Heavy 10L, so YMMV.

Bill in OKC 

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better

On Thursday, June 2, 2022, 09:03:10 AM CDT, rlm_mcv via groups.io <rlm_mcv@...> wrote:

I am having trouble with this part of your statement also. "Remember that the narrow end goes in the adapter, not the large end." 

The whole idea of a taper is to hold a tool or adapter.  That includes keeping it from turning within the bore.  The adapter already is only about 1/2 the length of the full taper and has no hold on the tang so why would you size for the small diameter and reduce the holding power even more?

On Thursday, June 2, 2022, 08:44:31 AM CDT, Bill in OKC too via groups.io <wmrmeyers@...> wrote:

My adapter for the Heavy 10L is 1-5/8" OD at the big end. It's .940" ID, with a wall thickness of 0.350" An MT 4 taper is 1.195" OD at that point on the taper. That gives you a wall thickness of 0.255", and that's thicker than the wall on my MT3-MT4 taper adapter. Only about 2/3rds of the taper goes into the spindle adapter. It won't be that much bigger than a #3. Remember that the narrow end goes in the adapter, not the large end. 

Found my MT3-MT4 adapter sleeve, wall thickness is 0.170".

I calculated the taper on my adapter some time back. Got  about 0.6148, table I have says an MT4.5 is 0.624. I am assuming I calculated that taper correctly, which is maybe not a good bet. :)

HTH!

Bill in OKC 

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better

On Wednesday, June 1, 2022, 12:20:18 PM CDT, rlm_mcv via groups.io <rlm_mcv@...> wrote:

I would check closer before making that MT4 as I think it would be a very thin sleeve and could prove it's self problematic in use and removal.

On Wednesday, June 1, 2022, 12:15:06 PM CDT, Bill in OKC too via groups.io <wmrmeyers@...> wrote:

Might want to add an MT4 while you're at it. Just in case. It will be a while before I need one, but the Smithy CB-1220XL 3-in-1 machine my brother decided I needed has an MT4 spindle, MT3 tailstock, and came fairly well tooled for a lathe that never got used. My Atlas TH42 uses MT3/MT2, and I somehow wound up with a fairly nice little chuck on an MT1 taper long before I got my first lathe. The Atlas MF milling machine uses MT2, also.  Having the variety of adapters means you don't have to be so careful as to what Morse-tapered tooling you buy. ;) 

Bill in OKC

William R. Meyers, MSgt, USAF(Ret.)

Aphorisms to live by:
SEMPER GUMBY!
Improvise, Adapt, and Overcome.
Physics doesn't care about your schedule.
The only reason I know anything is because I've done it wrong enough times to START to know better

On Wednesday, June 1, 2022, 12:05:52 PM CDT, rlm_mcv via groups.io <rlm_mcv@...> wrote:

I have not but would say that is your call.  You can also ream the finish internal taper using a Morse Taper finish taper in the tail stock.   I would only do this turning the spindle by hand not under power. 

Conciser making MT1- MT2- MT3 adapters and a blank or two while you are setup?

On Wednesday, June 1, 2022, 11:50:18 AM CDT, Rangelov <rangelov@...> wrote:

That will make it easier to hold and keep it true.

Should mark spindle and adapter in case the adapter is removed and reinstalled.  Probably unnecessary since is probably true. But why not?