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Spindle
04-03-2009, 03:10 PM
I need to use an engine hoist to lift my 12" rotary table. Should I use a plate with an eye mounted to the table t-slots, or a side mounted canitlevered bracket?

dockrat
04-03-2009, 03:30 PM
I dont think clamping a plate to the top of the table and lifting is a good idea but ya'all can call me wrong. Just make a sling....simpler than a cantilevered lifting plate. Slip an eye bolt into the clamping slot on the rtab.

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

http://i253.photobucket.com/albums/hh67/Dockrat1/IMGP1218Medium.jpg

J. R. Williams
04-03-2009, 06:07 PM
I made a fixture that bolts to the side of the table with an arm that extends over the table with a lifting eye welded at the C.G. of the unit. The fixture is welded. Easy to install and use to move the head.

JRW

JoeFin
04-03-2009, 06:16 PM
I had an 18" Troyke (300lbs) that I used to lift that way.

Now I have a 12" Yusa I can just pick up - but i have to think about it first

Spindle
04-03-2009, 06:20 PM
Mine doesn't have any slots or holes in the ends, just 2 deep pockets. It looks like they're made for a lifting fixture which i'm building now.

JoeFin
04-03-2009, 06:37 PM
Mine doesn't have any slots or holes in the ends, just 2 deep pockets. It looks like they're made for a lifting fixture which i'm building now.

Got a picture of those slots

lane
04-03-2009, 07:37 PM
I just use a bar bolted across the table with a eye bolt in the center . Lift with hoist . Easy and fastest way to do it . Every shop I ever worked in did it that way . Want hurt a thing , and no chance of it slipping.

Spindle
04-03-2009, 08:04 PM
Got a picture of those slots

I'll work on that in the next few days. Why isn't there was a "manage attachments" option here.

Rich Carlstedt
04-03-2009, 09:08 PM
The simpliest method is to put two Tee Nuts into the slots, push to the middle, and then get some eyebolts with the same thread and screw them into the nuts. put your sling etc through them and pull away.
no fixtures needed, and if the lift is from a single point, the slings will keep the eyes together.This method also allows some allignment flex for setting on the table
Rich

Spindle
04-04-2009, 12:02 AM
That's the way I'd like to do it, but I've never had a rotary table before now and don't know the do's and dont's.

derekm
04-04-2009, 07:46 AM
The 250mm Fritz Werner has a central hole with 16mm thread.
So I took a 16mm bolt, cut the head off, then cross drilled it 9mm and attached a D shackle.

Spindle
04-04-2009, 09:45 AM
I like that, but I don't think mine's threaded.

derekm
04-04-2009, 06:48 PM
I dont think clamping a plate to the top of the table and lifting is a good idea but ya'all can call me wrong. Just make a sling....simpler than a cantilevered lifting plate. Slip an eye bolt into the clamping slot on the rtab.
...


I dont think you need to worry about the slots.
The shear area in each T slot is approx 2 x 3/4" x 1/4" = 3/8 sq in
shear strength of grey cast iron = 58,000 psi => the strength of one slot is around 22,000 lbs. Thats a safety factor of 100 to 200 on the weight of the rotab.
You endanger the slots more tightening up on a workpiece than you do lifting the rotab.

Spindle
04-04-2009, 08:30 PM
I have no doubt about the slots being robust enough for the task. I am more concerned about the weight of the table being suspended by a gear mechanism designed for the horizontal forces of rotation, not vertical force of suspension. Although mine does have 2 lockdown clamps opposite each other that would probably eliminate that potential problem.

dockrat
04-04-2009, 08:37 PM
I am more concerned about the weight of the table being suspended by a gear mechanism designed for the horizontal forces of rotation, not vertical force of suspension.

That was my concern also. I should have stressed that. I'm sure the slots would be fine. Just didn't want to overstress those highend chicom bearings in mine :D

oldtiffie
04-04-2009, 09:08 PM
I made a fixture that bolts to the side of the table with an arm that extends over the table with a lifting eye welded at the C.G. of the unit. The fixture is welded. Easy to install and use to move the head.

JRW

That seems a really good idea JRW.

I can just about visualise it - do you have a pic or a scanned sketch that you can post please?

Rich Carlstedt
04-04-2009, 11:01 PM
The two clamps easily support the weight of the table.
Rich

J. R. Williams
04-05-2009, 11:11 AM
Oldtiff
I do not have a photo of the lifting bracket. The bracket has a flat plate, 1/4" thick steel, that bolts to the pad area of the table (the flat for the vertical mounting) with a steel bar (1/2" x 2") welded to the plate. Then with a little trial the center of gravity is determined to locate the place to weld on a lifting eye (5/16" steel bar stock) for a hoist hook. The flat plate is tapped for two 3/8" x16 socket head cap screws. This fixture is used to lift the table from it's storage box up to the mill table. Storing the unit in a closed wood box when not in use keeps it clean and dry. I use a small chain hoist to lift the rotary table and my 9" dividing head. The hoist is mounted on a shop built jib crane arm that is mounted to the side of the mill. It has a nominal 6 ft long arm made from "unistrut channel".

JRW

derekm
04-05-2009, 12:16 PM
Heres a another way that works for rotabs with radial slots

Image two C shaped pieces of metal made to go from the bottom of the rotab to the bottom of the rotab slots. With the top of the "C" in the Rotab slot, so the the sides of the rotab slots locate the "C" sideways, and the bottom of the C under the Rotab. The bottom of the "C" is the right width and depth to go inside the mill table slots, with the rotab flat on the mill table.

The tops of the "C"s have 2 holes which enable 2 bars to befastened on either side of the "C" tops, with bolts and pins and so to join the "C"s together across the top of the rotab. one C is bolted the other pinned

In the middle of the joining bars there is a hole for a shackle pin above the the CG.

The cradle cant slide and the rotab cant topple as the slots in the Rotab are located on the "C"s.
The shear strength of the bottom of the "C" is well above the weight ( 2 x 1/2" depth x 3/8" width = 3/8" Sq inch => 22,000lbs) by two orders of magnitude
The rotab is supported by the base and and the cradle is quickly, easliy and securely attached without tools.

Spindle
04-05-2009, 02:37 PM
The Table in question:
http://i648.photobucket.com/albums/uu201/ironrelic/RTbottompocket1.jpg
http://i648.photobucket.com/albums/uu201/ironrelic/RTtoppocket1.jpg

derekm
04-05-2009, 05:35 PM
The Table in question:
http://i648.photobucket.com/albums/uu201/ironrelic/RTbottompocket1.jpg
http://i648.photobucket.com/albums/uu201/ironrelic/RTtoppocket1.jpg
in this case the "C"s go in the recesses or pockets rather than underneath the table and as before the rotab slots provide location not lift

Roy Andrews
04-06-2009, 12:22 AM
i have had my 12" troyke apart and can't imagine how lifting it with the table could possibly hurt it. the gears don't hold the table on and you would think a heavy cut trying to pound that table around is a lot more force than just picking it up.the nut and boss that hold the table to the base have got to be around 4". cant imagine the force it would take to stress that.

oldtiffie
04-06-2009, 02:51 AM
Oldtiff
I do not have a photo of the lifting bracket. The bracket has a flat plate, 1/4" thick steel, that bolts to the pad area of the table (the flat for the vertical mounting) with a steel bar (1/2" x 2") welded to the plate. Then with a little trial the center of gravity is determined to locate the place to weld on a lifting eye (5/16" steel bar stock) for a hoist hook. The flat plate is tapped for two 3/8" x16 socket head cap screws. This fixture is used to lift the table from it's storage box up to the mill table. Storing the unit in a closed wood box when not in use keeps it clean and dry. I use a small chain hoist to lift the rotary table and my 9" dividing head. The hoist is mounted on a shop built jib crane arm that is mounted to the side of the mill. It has a nominal 6 ft long arm made from "unistrut channel".

JRW

Thanks JRW as that has cleared it up for me. I had it in mind that the "table" was on the mill and not on the rotary table.

Spindle
04-06-2009, 05:07 PM
Thanks for all the input and advice. I haven't had one apart, or even used one yet, and I didn't want to break it on its way to the first project.