Sensitive drill sleeve

[WobblyHand]

Recently picked up a small 0-3mm Albrecht chuck and Jacob's arbor with the idea of making a sensitive drilling rig for my lathe. Here's a CAD picture of it. Originally I thought I'd try a MT3 taper to go directly into my tail stock, but I've given up on that idea, since I've never made a Morse taper before. Hopefully this is a little easier to implement. It has a 1/2" shank so I can fit it in my existing drill chuck. I'm using a 7/8" diameter piece of 1144.

I'm not sure how well this will work, but it's worth a try. The Jacob's arbor mics at 0.4995" or so, so I'm hoping I can ream the hole to 0.5000" for a decent somewhat snug sliding fit. The design is sort of based on Joe Pie's video, or my distorted understanding of it. If it works out, I'll attach the drawings in this thread. The little hole in the side is to let out the air, as the arbor will form a piston in the sleeve. Due to the center section of the arbor, it will support drilling holes only 22mm deep, (the outer section is 23mm long), but this is good enough for tiny holes that I need to do.

 

[WobblyHand]

Made a minor change on my drawing, changed the shank end to 13mm rather than 1/2" since my Rohm chuck is 0-13. Not much, but it's 0.3mm in diameter larger.

Turned the sleeve for 40mm to 13mm in diameter. Then flipped the piece (I'm using a 7/8" ER-40 collet) spotted the faced end and drilled with a 15/16" drill to a depth of ~74mm. Since I don't have a DRO on my tailstock, AND I don't have 74mm of travel, I did it in two steps. Then I drilled it to 31/64" diameter to depth. Then I double checked the Jacob's arbor and measured it as 0.4995" in diameter. So I grabbed my reliable APT 0.5000" reamer and reamed the hole. 'Twas a perfect fit! Since there's only 0.0005" total clearance, the arbor acts as a piston and the air pressure resists pushing the arbor into the hole, until the air slowly leaks out.

Next, I need to drill a weep hole at the bottom of the hole, so this resistance doesn't happen. Hmm, left my phone in the shop, have to go there so I can take a picture of what I have so far.

Slowly getting there!

 

[Ulma Doctor]

Very nice, I need to follow your lead on this one

 

[woodchucker]

Are you going to key it so you can use it in the mill and the tail stock?
Going to spring load it?

 

[WobblyHand]

Are you going to key it so you can use it in the mill and the tail stock?
Going to spring load it?

Not for this version. I'm going to keep it simple and see how it goes. If I think it could be improved, I can always make another sleeve. I just need this for my lathe at the moment. Adding a spring retractor wouldn't be that hard.

 

[Chip Hacket]

Made a minor change on my drawing, changed the shank end to 13mm rather than 1/2" since my Rohm chuck is 0-13. Not much, but it's 0.3mm in diameter larger.

Turned the sleeve for 40mm to 13mm in diameter. Then flipped the piece (I'm using a 7/8" ER-40 collet) spotted the faced end and drilled with a 15/16" drill to a depth of ~74mm. Since I don't have a DRO on my tailstock, AND I don't have 74mm of travel, I did it in two steps. Then I drilled it to 31/64" diameter to depth. Then I double checked the Jacob's arbor and measured it as 0.4995" in diameter. So I grabbed my reliable APT 0.5000" reamer and reamed the hole. 'Twas a perfect fit! Since there's only 0.0005" total clearance, the arbor acts as a piston and the air pressure resists pushing the arbor into the hole, until the air slowly leaks out.

Next, I need to drill a weep hole at the bottom of the hole, so this resistance doesn't happen. Hmm, left my phone in the shop, have to go there so I can take a picture of what I have so far.
View attachment 500963
Slowly getting there!

Very nice!

 

[WobblyHand]

Drilling the hole was non-eventful. I had left my dividing head on the mill from a previous project. Made it easy since it was already indicated and set up.

Then I made a collar on the end of the sleeve, although I don't think it is necessary for use at all. Took a piece of 1.25" 1144 steel and knurled it on my mini-lathe. (I had made a scissors type knurler for it several years ago. I don't have an equivalent on my 10x22 yet - sounds like a pending project...). I also drilled it out to 3/4" using a 3/4" MT2 drill in the tail stock. I could have done that in my 10x22 if I had a MT3 to MT2 sleeve, but nope, don't have one. Then swapped it back to my 10x22 and stuck the stock in a 32mm ER-40 collet. I then finished boring it to about 7/8" - or so I thought. When I mic'd the bore out, it was bigger than the sleeve, but it was too tight to assemble. Then I parted the work piece part way, then chamfered both edges, and finished parting the piece. I thought if I slit it perhaps it might spring open a little more.

The plan was to slit it and put in a screw to tighten the collar. That is what I had designed. But as I was staring at it, I wondered if I could simply just press it into place, so I did just that. I could barely insert the sleeve into the collar. Then I used my machinist hammer to tap it in. When it was a mm or two in place, I stuck it in my arbor press and pressed the collar flush to the front face of the sleeve. If it ever moves or comes off, I'll slit it and add a screw.

Assembled the shank into the sleeve with a drop of light machine oil. Pretty low friction, but can't feel any slop. So this project is done, (as far as I know,) I'll have to try it out soon! Most likely tomorrow. I have a 1.5mm diameter hole to drill.

Oh yeah, I promised some plans. Here they are. I made the shank 13mm. And the collar (ring) is solid, since the fit was so snug. Maybe next time I'll build it to print... But seriously, I need to see how well it works before putting much more into it.

 

[Chip Hacket]

Drilling the hole was non-eventful. I had left my dividing head on the mill from a previous project. Made it easy since it was already indicated and set up.

Then I made a collar on the end of the sleeve, although I don't think it is necessary for use at all. Took a piece of 1.25" 1144 steel and knurled it on my mini-lathe. (I had made a scissors type knurler for it several years ago. I don't have an equivalent on my 10x22 yet - sounds like a pending project...). I also drilled it out to 3/4" using a 3/4" MT2 drill in the tail stock. I could have done that in my 10x22 if I had a MT3 to MT2 sleeve, but nope, don't have one. Then swapped it back to my 10x22 and stuck the stock in a 32mm ER-40 collet. I then finished boring it to about 7/8" - or so I thought. When I mic'd the bore out, it was bigger than the sleeve, but it was too tight to assemble. Then I parted the work piece part way, then chamfered both edges, and finished parting the piece. I thought if I slit it perhaps it might spring open a little more.

The plan was to slit it and put in a screw to tighten the collar. That is what I had designed. But as I was staring at it, I wondered if I could simply just press it into place, so I did just that. I could barely insert the sleeve into the collar. Then I used my machinist hammer to tap it in. When it was a mm or two in place, I stuck it in my arbor press and pressed the collar flush to the front face of the sleeve. If it ever moves or comes off, I'll slit it and add a screw.

Assembled the shank into the sleeve with a drop of light machine oil. Pretty low friction, but can't feel any slop. So this project is done, (as far as I know,) I'll have to try it out soon! Most likely tomorrow. I have a 1.5mm diameter hole to drill.
View attachment 501053View attachment 501054
Oh yeah, I promised some plans. Here they are. I made the shank 13mm. And the collar (ring) is solid, since the fit was so snug. Maybe next time I'll build it to print... But seriously, I need to see how well it works before putting much more into it.

Are you sure Shirley U Jest approved those drawings? I happen to know her and she's always jest one step ahead of the game!

 

[Chip Hacket]

I really like your project. I started a similar one but wasn't crazy about the results. You may have just given me the inspiration to try again.

 

[WobblyHand]

I really like your project. I started a similar one but wasn't crazy about the results. You may have just given me the inspiration to try again.

It's simple, which is it's advantage. Hopefully it is good enough without having to have difficult to machine components. I need simple stuff, because I'm not that good of a machinist, nor are my machines very fancy.