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terry_g
10-24-2009, 12:11 PM
I am planning on buying a rotary table for my 8" x 30" Craftex mill.
The three I am looking at are :

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B062ST

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B062

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B2485

I am curious as to which one to order. The one with the 3MT bore would easier to centre a 3 jaw chuck on. Turning an arbour that fits in the 3MT taper and extends far enough that the of the chuck lightly clamp it should be adequate for centring the chuck I would think.
What advantage would the 24mm bore have?
The six inch one comes with the tail stock and dividing plates, Would the extra 2" inches be worth the extra investment?
the dividing plates for the eight inch rotabs are $139.00 extra I would build the tail stock if needed.

Thanks
Terry

Carld
10-24-2009, 12:33 PM
Your asking for opinions so mine is for #3 on the list. While it is only 6" it has the tail stock and plates.

I prefer a straight hole in the center of the table because it's easier to make adapters to hold the part on.

Paul Alciatore
10-24-2009, 02:13 PM
I have a 10 inch RT with a 3MT bore and I like it. A tapered bore will allow inserting a centering pin without any side play. A straight bore will always have some side play and will therefore introduce some centering error if you are using a fixture to speed things up.

Here is a drawing of one such pin that I use to aid in centering both the table on the mill and the part on the table. Ignore the 2MT designation on the drawing it is actually 3MT.

http://img.photobucket.com/albums/v55/EPAIII/RotaryTableCenterFinder.jpg

Since my lathe (SB9) also has a 3MT spindle bore, I can just buy (they only cost a few dollars) a 3MT pin with enough extra meat on the other end and put it directly in the lathe spindle for accurate machining of the other end. This is probably the most accurate way of mounting a part for turning and is a great advantage.

The OD of the protruding end is a match for the bore in some parts I needed to mount. The part can be just dropped on that pin for instatant centering so changing parts in a multiple run is very fast. The 0.400" ID was drilled, then bored for maximun concentricity, and finally reamed to the final size for maximum accuracy there. A 0.200" diameter edge finder will easily fit in the hole and can be used to center the RT on the mill. It requires several cycles of X then Y then X again but it only takes a minute or so to get within a few tenths. When I do this I always move each axis in ONE direction only to avoid backlash problems. I choose the 0.400" size to provide some room for these motions and to provide the same 0.100" offset that the edge finder will normally have when finding an outside edge. This avoids confusion.

The tapped hole in the center of the pin is for easy removal. A 1/4" x 4" bolt with a sliding weight (reverse hammer) will quickly and safely take it out without any need to access the back of the RT.

Similar things could be done with a straight bore in the RT, but the accuracy would be less. It is almost easier to make tapered adapters than straight ones because the centering problems and errors instantly disappear.

Pherdie
10-24-2009, 02:42 PM
I have (and would purchase again) the eight inch with MT3, division plates and tail stock. I would suggest the same for anyone who asks.

Even with the eight inch table, I have frequently been pressed for clamping room on a number of smaller pieces. I can't even imagine trying to deal with that same issue in a six inch table unless making tiny objects (< 4" in dia.).

For me the MT3 taper provides a great quick reference for mounting items. I have an MT3 shank turned at one end to 1/2" diameter. Drill a 1/2 inch mounting hole in your stock, drop the MT3 shank in the table and the stock onto the 1/2 cylindrical end of the MT3 adapter, clamp, and you're set.

You can also use the same adapter to quickly set your rotary table up on your mill. Leave the table loose on the mill insert the MT# shank. Put a 1/2" collet in the quill, lower the collet down onto the 1/2 diameter portion of the MT3 shank while allowing the rotary table to 'float' on the mill table, then tighten the collet. Next, move the mill table so the rotary table is positioned as desired and clamp the rotary table to the mill table. Unlock the quill from the MT3 adapter and zero your mill controls.

Note: In what is probably a futile attempt to placate policing purists, I state that this is not the most accurate way to set up a table and stock. It is a quick and useful way I use to frequently accomplish tasks that are less demanding of absolute precision.

Back to the issue at hand. In so many words I think the MT#3 taper is far more useful than limited as compared to the 24mm through bore. The only thing I see more appealing in the six inch unit is it's much smaller weight and footprint.

Go for the 8" and dividing plates, you'll be glad you did.

Fred

uncle pete
10-24-2009, 03:23 PM
I have a 6 in. Vertex and other than initial cost and your mill is big enough, I'd say get an 8 in. Far easier for set up, Room to work, Ect. I plan on buying a 10-12 in. in the future with a MT3 center hole.

Pete

Paul Alciatore
10-24-2009, 05:51 PM
Watch out for the 12 inch size. I find I can barely move my 10 inch. I even dropped it once due to oily hands.

JoeFin
10-24-2009, 06:57 PM
Watch out for the 12 inch size. I find I can barely move my 10 inch. I even dropped it once due to oily hands.

At what age do you mount a small sturdy jib crane next to the mill

I'm just planning ahead.....

I have a 12" Yusa and a L&W Dividing Head and at 52 I should probably start making plans. I had a Phase II 6" rotary table, but some guy older then me traded me out of it with the 12" Yusa. But by comparison the Yusa out-performed the Phase II in every way

barts
10-24-2009, 07:29 PM
I've been considering the 10" Phase II vertical/horizontal table... but I can't seem to find out: is the center hole MT3? Or a straight bore?

- Bart

uncle pete
10-24-2009, 08:13 PM
I bought a cheap engine hoist, When I'm too old to pump the handle I won't even know what the shop tools are for. A 150-200 lb rotary table will be a trivial matter.

Pete

TexasTurnado
10-24-2009, 11:29 PM
I've been considering the 10" Phase II vertical/horizontal table... but I can't seem to find out: is the center hole MT3? Or a straight bore?

- Bart

Mine (circa 1990, and made in Taiwan) has a MT3 - may or may not be the case for those from China.

oldtiffie
10-25-2009, 12:00 AM
I am planning on buying a rotary table for my 8" x 30" Craftex mill.
The three I am looking at are :

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B062ST

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B062

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B2485

I am curious as to which one to order. The one with the 3MT bore would easier to centre a 3 jaw chuck on. Turning an arbour that fits in the 3MT taper and extends far enough that the of the chuck lightly clamp it should be adequate for centring the chuck I would think.
What advantage would the 24mm bore have?
The six inch one comes with the tail stock and dividing plates, Would the extra 2" inches be worth the extra investment?
the dividing plates for the eight inch rotabs are $139.00 extra I would build the tail stock if needed.

Thanks
Terry

Hi Terry.

Can you please post a link to your mill?

There is no point in putting a "too large" (or too heavy) rotary table on your mill. If the rotary table over-hang unduly limits the "in" travel on your "Y" slide it is quite counter-productive. The milling spindle should be able to be put "forward" of the rotary table axis.

It is quite easy and very effective to make a face-plate for your rotary table in the event you need a bigger surface - eg. to make a 6" top the same as an 8" top without the cost or "hassle" and at quite reasonable expense.

I have both a 6" and an 8" rotary table/s. The 6" gets the most use as it is handy and light where-as the 8" is heavy and cumbersome. Both of mine are "Vertex" (China) and I am very happy with them.

My 8" will only fit on my HF-45 dove-tail column mill where-as the 6" one will fit and work very well on both my HF-45 and Sieg X3 mills.

My 6" has 3 slots (and not 4) as it fits in very well with the 3-jaw chuck and collet chuck that I use (both also fit straight onto my lathe). The 8" has its own front-mounted chuck and face-plate.

I never use the bore/s in my rotary tables to either "centre" a job on them or to centre the rotary table under the mill spindle axis.

terry_g
10-25-2009, 09:37 AM
This is the mill that I will be using the rotary table on.

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B048

Terry

ammcoman2
10-25-2009, 10:03 AM
I have the same size mill sold by KBC, and a 6" Vertex R/T that came with it. I've since made a 9" table top(?) to fit on it as there are many instances, as others have said, where one needs more space for clamping.

The only possible drawback with an 8" R/T would be the weight. This is something one is aware of as one gets older!

There is definitely enough space on this mill for an 8" unit.

Geoff

BigBoy1
10-25-2009, 10:10 AM
My rotatry table came with a center with a Morse #3 taper. I wanted to mount a four jaw lathe chuck to the rotary table for holding items. My four-jaw chuck has a threaded back mounting arrangement. I obtained a Morse taper extension

http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=2613664&PMAKA=214-8624

and cut off the portion of the extension at the taper pin knock-out hole. I then treaded the stub to match the four-jaw chuck mounting thread. I use the Morse Taper stud on the back of the four-jaw chuck to mount the chuck to the roraty table.

JoeFin
10-25-2009, 10:19 AM
This is the mill that I will be using the rotary table on.

http://busybeetools.ca/cgi-bin/picture10?NTITEM=B048

Terry

Looks just like the Ol' Grizzly Mill I used to have. It was a nice easy accessable work platform. If I remember right the table load was 200 Lb Max which will hold any RT or DH we are going to lift.

Rich Carlstedt
10-25-2009, 11:30 AM
Go with the six inch RT for the following reasons.
Looking at all of them :

1. These are foreign made tools.
I don't have a problem with that , except that Quality specifications are hard to come by. So how accurate is the taper/straight Bores in both concentricity (1) and Perpendicularity (2) to the axis ?
A taper is worthless if the bore is off.
A straight bore can at least be plugged and rebored, or as I have done on some cheap RT'S - remachined the bore so it was concentric. If its straight, thats pretty easy. As far as plugs being sloppy, I never make them that way, They are always tight and need to be lightly pressed into the bore.They are removed by driving out from the backside.
Such plugs are more easily made than modifing a taper shank, and cheaper as well.

2. The size of your mill is such that the RT can overwhelm the table, in both weight (if not centered on the knee) and when standing vertical off to the side . You don't have a deep knee to suppport offset loads without deflection in my opinion.

3 The kind/size of work you expect to do has a great bearing on the decision.
If you intend to do 6 inch work, then the 8 inch may be better, but I suspect you will be under 4 inch most of the time based on equipment choice.

4. The dividing plates give you supreme use of the RT. You will be able to cut gears or cams with these attachments, as well as do shaft keyways (timed) or splines. Just realise that a 8 inch RT and a 8 inch tailstock take so much room on the X axis (you only have 30") that room must be had for spindle clearance.

5. The 3 "T" slots on the table are undesirable to me
I much prefer 4 slots for clamping. many times I use two clamps at 180 degrees. A 3 slot forces you to use 3 clamps, or the work will be unevenly clamped on one side ! A no-no for good work.

Well, anyway this is my opinion
Rich

Lew Hartswick
10-25-2009, 11:38 AM
At what age do you mount a small sturdy jib crane next to the mill

I'm just planning ahead.....

:-) I'm 77 and at school (I volunteer at) I made some "fixtures"out
of 2 x 4 s to be able to slide the 12" rotary table on and off the
mill table and a FLAT top cart and onto the storage bench. NO WAY
can I lift that sucker. :-)
...lew...

dockrat
10-25-2009, 12:09 PM
At what age do you mount a small sturdy jib crane next to the mill

I'm just planning ahead.....

I made a block and tackle set and attached it over my mill.I can lift my 10" table high enough with one pull of my left arm with it and guide it onto the table with my right arm.

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1188Medium.jpg

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1215Medium.jpg

JoeFin
10-25-2009, 01:29 PM
I like the setup Dockrat

Just send the table 100% X travel, load and then move into position. I'll probably look into fabing up the pullys and use a "Fixed" jib-crane arm to move it on and off the cart and mill like Lew uses.