A Little Trick

[Phil Anderson]

A little trick I learned. If you have a live center like this Oneway or other knock-offs like that which came with my Jet lathe, you can lay a standard pencil along it and make about a two inch circle. That allows you to make a tenon or a recess that fit standard 50mm jaws. Might have to adjust slightly to get the exact fit you want, but this will get you very close.

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[John K Jordan]

[COLOR=#1D2129]A little trick I learned. If you have a live center like this Oneway or other knock-offs like that which came with my Jet lathe, you can lay a standard pencil along it and make about a two inch circle. That allows you to make a tenon or a recess that fit standard 50mm jaws. Might have to adjust slightly to get the exact fit you want, but this will get you very close.

That's a good trick! Someone who doesn't know this may sometimes see a demonstrator cut a tenon or recess and wonder how he got it right without measuring! They are probably just eyeballing it with the live center close.

When cutting a lot of recesses for 50mm jaws I've started using another shortcut - a 2-1/16 Forstner held in an end mill holder/adapter with a #2 morse taper that fits into the tailstock. The 3/8" size holds my carbide Forstner bits perfectly. The bit plus adapter is shorter and is sturdier (and shorter) than holding with a Jacob's chuck. This, of course, only works if the piece is supported by something other than the tailstock!

https://www.amazon.com/gp/product/B01MXSP25W
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JKJ

[Bill Jobe]

Terrific idea. I've been trying to create a uniform size to make things easier to from one roughed piece to another. My way of doing that is with a set of calipers. This looks to be superior.

[Steve Arnold]

Great idea!

I love learning little shortcuts like this.

[Pat Scott]

When cutting a lot of recesses for 50mm jaws I've started using another shortcut - a 2-1/16 Forstner held in an end mill holder/adapter with a #2 morse taper that fits into the tailstock. The 3/8" size holds my carbide Forstner bits perfectly. JKJ

Not trying to hijack the thread, but what brand of carbide forstner bits do you use that are 2-1/16"? I'd like to buy a 1-1/16" carbide bit but can't find anyone that makes one.

[allen thunem]

try amazon i found one there or else try 27mm as your search parameters

[Brandon Speaks]

Would 2 1/8th work for the Forstner bit or is 2 1/16th better. I ask because Menards has that size in stock vs ordering online.

[John K Jordan]

Not trying to hijack the thread, but what brand of carbide forstner bits do you use that are 2-1/16"? I'd like to buy a 1-1/16" carbide bit but can't find anyone that makes one.

I found 2-1/16" carbide bits on Amazon.
I see this 1-1/16" carbide on Amazon: https://www.amazon.com/Roman-Carbide-DC1853-Forstner-16-Inch
My only experience with the Roman Carbide brand is from one 2-1/16" bit I bought - it seems fine. This one has a hex shaft for secure mounting in a Jacobs chuck and seems to be well made.

The two Forstner bit sets I have in standard "inch" sizes don't have bits in 1/16" increments. I do see some on Amazon, for example, in 1/16" increments: https://www.amazon.com/Piece-Forstner-Wooden-Peachtree-Woodworking/dp/B00408WUZG but haven't found a set like this in carbide.

I did buy several sets of metric carbide bits on Amazon to get sizes between and close to those I needed. I found that every (fairly cheap) set I bought drill holes slightly bigger than the indicated size, some worse than others. This was the most precise: https://www.amazon.com/gp/product/B01LSAD7BO/ but unfortunately it doesn't have the 27mm size. In fact, I don't remember seeing any metric sets with 27mm.

BTW, I prefer a good quality HSS bit for precise holes since in my experience the carbide tends to be a little "sloppier". However the carbide lasts and lasts and is perfect for recesses and much work on the lathe.

JKJ

[Reed Gray]

I haven't seen him mention it in his videos, but Glenn Lucas has a set up on his tailstock that is permanently mounted and sticks out the back side with indicators for two different sizes of recess and/or tenons. Pointer type things, and I guess they go around the live center. Pretty simple to do. I just use dividers that are super glued in place, and hang on the wall. The above works too...

robo hippy

[Damon McLaughlin]

Thank you for the tip, I'll have to give that a try. I've also done what JKJ does as well though I use a 2" forstner bit (all I have) and fine tune it with a skew.

[John K Jordan]

Would 2 1/8th work for the Forstner bit or is 2 1/16th better. I ask because Menards has that size in stock vs ordering online.

2-1/8" works fine, at least for 50mm Nova jaws. I use that size when drilling on the lathe so I can use the 3/8" end mill holder instead of a Jacobs chuck. (since my 2-1/16 bit has a hex shank)

The difference is small, but according to accepted wisdom (and chuck maker's recommendations) the recess or tenon should be as close as possible to the closed diameter of the chuck jaws. This puts more jaw area in contact with the wood. (Jaws are machined in a circle when closed or nearly closed.) The difference between 2-1/16" and 2-1/8" is not that much. There is a big difference in holding "power", however, in expanding 2" jaws into a 3" recess - the only contact will be in the rounded center of each jaw.

When turning fidget spinners I went to great length so make expanding chuck jaws that were very close to the 20mm hole drilled for the center bearing. It was surprising how well a very small expansion force held when the two diameters are nearly identical. Some of my designs would have split if tightened more than just a tiny bit.

Also, I found a larger recess makes less difference in softer wood since the jaws press into the wood for good contact all the way around. It would be more important for hard woods like ebony or for acrylics and metals. (I've never turned plastic or metals in a recess but plenty with tenons and I try to size the tenon appropriately.)

JKJ

[Thomas Canfield]

A little trick I learned. If you have a live center like this Oneway or other knock-offs like that which came with my Jet lathe, you can lay a standard pencil along it and make about a two inch circle. That allows you to make a tenon or a recess that fit standard 50mm jaws. Might have to adjust slightly to get the exact fit you want, but this will get you very close.

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An additional tip: a block of wood about 3/4" x 1-1/2" when placed on the live center will give a pencil line about 3" for #3 chuck and 5" for #4 chuck. Try it and see. Sure is handy for larger chucks.

[ELY WALTON]

As I recall, Mike Peace uses this trick in some of his u-tube videos... great idea!

Ely

[Lamar Wright]

As I recall, Mike Peace uses this trick in some of his u-tube videos... great idea!

Ely

Good tip Phil and yes Ely Mike peace uses this method to mark for Recess/tenons.

[Leo Van Der Loo]

The nice thing when having and using the standard Oneway chuck and jaws, I’m not bound to use and have to make these precise recesses, I just make them the appropriate size I think goes with the size of the turning, and that can be anything the chuck can open up to.

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[Bob Bergstrom]

I start bowls and boxes between centers. Rather than removing my chuck I slip my drive centers or starter plate into the chuck and mount the blank. The second photo is my Robust slip drive center modified to put teeth in it. The third is my starter plate for starting bowls. I drill two holes into the bark of a natural edge blank 2 7/8" apart. They act as imbedded pins to rotate the blank.
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