I decided to make a 4 way tool post for a fun shop project. Cold up north an I’m getting cabin fever. Anyway I have a 2”x4”x4” piece of 4140 normalized steel block here. In my research I haven’t found what the correct dimensions the tool post should be for a 11”x36” metal lathe. This will hold 1/2” tooling. Could someone that has a comparable size machine and has a 4 way measure theirs? I would be very helpful.
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Shop made 4 way tool post help
- Thread starter Brad125
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- Dec 27, 2014
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Justs a suggestion, find the distance from the top of your compound to the center of the spindle, subtract 1/2 inch! That's the bottom of your 1/2 inch tool.
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- Apr 16, 2019
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Making your own I would see if you could have a “ rocker “ on at least one of the four , it sure would be handy when using HSS tools . Heres something of what I’m talking about https://www.micromark.com/Rocker-To...MI8o6cqILW_AIVCKbICh3UqgQsEAsYBCABEgJHCfD_BwE
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Clever idea
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- Oct 31, 2016
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The dimensions are not that critical except for the slot. The top of the slot has to be above centerline to allow room to shim the tool bit to centerline because the tip of the tool bit will be lower than the top of the tooling. The bottom of the slot has to lower than 1/2" from centerline again to allow room for shims.
The easiest way to find centerline is to make the 4 way except for the slot. Put a sharp dead center in the spindle and install the 4 way on the lathe. Put the 4 way against the dead center and scribe a line using the cross slide. Scribe a second line a1/16" more or less above this line and a 3rd line around 5/8" below the second line. This will give you sufficient room to be able to shim the tool bit to centerline. Also make the slot slightly less that 1/2" deep. This way when you need to square the tool bit to the chuck you can place the tool bit directly against the chuck. Should also make the 4 way so that the slots are as close as they can be to the center of the 4 way. This will help with rigidity.
The 4 way on my craftsman 12x36 is 2 1/2" x 2 1/2." The height of the slot is 1/2." It is designed for 3/8 tooling. Your 4 way would need to be no more than 3"x3."
The easiest way to find centerline is to make the 4 way except for the slot. Put a sharp dead center in the spindle and install the 4 way on the lathe. Put the 4 way against the dead center and scribe a line using the cross slide. Scribe a second line a1/16" more or less above this line and a 3rd line around 5/8" below the second line. This will give you sufficient room to be able to shim the tool bit to centerline. Also make the slot slightly less that 1/2" deep. This way when you need to square the tool bit to the chuck you can place the tool bit directly against the chuck. Should also make the 4 way so that the slots are as close as they can be to the center of the 4 way. This will help with rigidity.
The 4 way on my craftsman 12x36 is 2 1/2" x 2 1/2." The height of the slot is 1/2." It is designed for 3/8 tooling. Your 4 way would need to be no more than 3"x3."
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- Oct 11, 2016
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So here's the deal: Your lathe will be different from other models of the same swing.
So bear with me and I'll describe what will work for YOUR lathe.... (FYI I use 4-way tool posts on all my 3 lathes even though I also own various types of QCTP - Aloris and Dixon)
1) Measure your shanks of your carbide tooling. HSS will always be 'out of spec' for your needs. For instance, say you use a lot of 12mm tooling, which is easy and cheap to get. This will be dimension A
2) Now turn a scrap piece of work to below 1" so you can use a micrometer on it. [do not remove it from the chuck] Dimension B
3) now for the tricky error-prone bit: measure as accurately as you can from the top of your compound to the top of the turned part. Dimension C
the *bottom flange thickness for your slot in your 4-way will be C-A-(1/2 B). If you mill this accurately, you will never need a shim for your 4-way tool post.
So bear with me and I'll describe what will work for YOUR lathe.... (FYI I use 4-way tool posts on all my 3 lathes even though I also own various types of QCTP - Aloris and Dixon)
1) Measure your shanks of your carbide tooling. HSS will always be 'out of spec' for your needs. For instance, say you use a lot of 12mm tooling, which is easy and cheap to get. This will be dimension A
2) Now turn a scrap piece of work to below 1" so you can use a micrometer on it. [do not remove it from the chuck] Dimension B
3) now for the tricky error-prone bit: measure as accurately as you can from the top of your compound to the top of the turned part. Dimension C
the *bottom flange thickness for your slot in your 4-way will be C-A-(1/2 B). If you mill this accurately, you will never need a shim for your 4-way tool post.
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- Apr 23, 2018
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If I had a dollar for how many clicks I give Dorian for this one catalog...
They have some great diagrams and a *worksheet* for sizing your tool post. You don't have to buy theirs, they freely give you the information.
They have some great diagrams and a *worksheet* for sizing your tool post. You don't have to buy theirs, they freely give you the information.
Couldn’t you just mount the tool post to the compound and put an 1/2 endmill in the chuck and mill out the slots for the 1/2” tools? Theory should say it would be dead nuts on center height…. I wasn’t going to do this I just seen a video where a fella made his like this.
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- Mar 27, 2022
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That would make the half inch shot at the center line. Meaning a half inch tool would be a 1/4” too high. Unless you shimmed the block a 1/4” up.