Transfering/ laying out holes for adapter plate.

[mac1911]

I am attempting to make a adapter plate for my lathe.
I have a smithy 1220
The spindle and flange are one piece and had 3 mounting holes with just enough access to install the bolts. Removing the spindle would be a choir.
Im no machinist and am a little stumped on a accurate way to get the holes in the correct locations on the adapter plate.
I was planning on machining the adapter to fit the flange on the spindle then removing the 3 jaw chuck and replacing the mounting bolts with hardened tipped set screws then using a draw bar to hold the adapter in place use the set screws to make the locations.
Im trying to make adapter for this 5” 4 way

 

[dirty tools]

Military training for me was
measure O.D.(outside diameter)for the new plate
measure bolt hole circle diameter
measure bolt center to bolt center

use cast iron for the backing plate

find center pilot hole it
scrib bolt hole Circle
scrib bolt holes

another way
cut a paper. Pattern

 

[Jim F]

Transfer screws ?

 

[mac1911]

Military training for me was
measure O.D.(outside diameter)for the new plate
measure bolt hole circle diameter
measure bolt center to bolt center

use cast iron for the backing plate

find center pilot hole it
scrib bolt hole Circle
scrib bolt holes

another way
cut a paper. Pattern

Been trying to find a piece of cast Iron. Scrap is not what it used to be in this area.

 

[mac1911]

Military training for me was
measure O.D.(outside diameter)for the new plate
measure bolt hole circle diameter
measure bolt center to bolt center

use cast iron for the backing plate

find center pilot hole it
scrib bolt hole Circle
scrib bolt holes

another way
cut a paper. Pattern

Cant get paper to sit all that flat , quick attempt just did not feel adequate.
Im probably going to have to get better lay out tools. If I try that route.

 

[pontiac428]

I can hit circular patterns every time with nothing more than a punch, scribe, metal scale, and a dividing compass. I believe the art form is called "layout" and used to have entire chapters dedicated to the practice in the textbooks. I learned the tricks in mechanical drafting, but it's the same thing that the ancient Greek scholars were doing four thousand years ago with chalk and string.

 

[Aukai]

If there is enough register to engage the chuck, these might work. Blind hole spotters

 

[pontiac428]

These are representations of exact methods for patterning holes on a circle. A rotary table is the easy way to machine the part, but you can map out the cartesian coordinates of each hole and just work it out on your mill table with a drill. You can find as many digits past the decimal you need, find center, and go to town.

 

[Janderso]

I am attempting to make a adapter plate for my lathe.
I have a smithy 1220
The spindle and flange are one piece and had 3 mounting holes with just enough access to install the bolts. Removing the spindle would be a choir.
Im no machinist and am a little stumped on a accurate way to get the holes in the correct locations on the adapter plate.
I was planning on machining the adapter to fit the flange on the spindle then removing the 3 jaw chuck and replacing the mounting bolts with hardened tipped set screws then using a draw bar to hold the adapter in place use the set screws to make the locations.
Im trying to make adapter for this 5” 4 way

Love the chuck!!

 

[mac1911]

These are representations of exact methods for patterning holes on a circle. A rotary table is the easy way to machine the part, but you can map out the cartesian coordinates of each hole and just work it out on your mill table with a drill. You can find as many digits past the decimal you need, find center, and go to town.

View attachment 438770View attachment 438767View attachment 438769View attachment 438768

I get it for those trained and working in the art. Im a complete beginner. I will have to read up more on layout.
I dont have a rotary table, eventually I will come across one. Like I did this chuck.