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Boring help needed...

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56type

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#1
OK guys here's where I'm at... I need to make a sleeve to adapt one part to another, and I have the O.D. spot on for a 0.001 in. press fit between the two pieces and have moved to the interior dimension. Interior needs to be bored to 0.661 in. I.D. for a length of 0.998 in. minimum. The O.D of the sleeve is 0.689 in. so the wall thickness will be 0.028 in. when finished. I'd rather get the boring done while everything is dialed in right now VS. try to swap ends and set up again, but my current boring bit won't reach deep enough to do the job. Here's the boring bit...

https://littlemachineshop.com/products/product_view.php?ProductID=1968

It will only reach in up to the step where the shank squares, just no clearance to keep it centered on the inside of the bore and let the square shank pass thru.
Here's the problem...I have an Atlas 10100 Mk.2 lathe with the lantern tool post & tool holders that take the 1/4 in. square tool bits. The boring bit that came in the beginner's set of tool bits from LMS just isn't quite long enough to reach the 0.998 in. depth, it falls short by 0.100 in. I currently have a 0.50 (1/2 in.) drilled hole (1.100 in. depth) started but can't go any farther since my drill bit selection is pretty limited (1/2in. is largest drill bit I have).

So does anyone have an idea on where to pick up a longer boring bar similar to the one in the LMS link I posted above that will fit the Atlas 10100 Mk.2 tool holders for the lantern tool post ?? Or is there something I'm overlooking being that this is my first time ever trying to use the boring boring bar inside a drilled hole where I can't see what's going on ?? I *REALLY* don't want to take the work piece out of the 4-jaw chuck and try to set it up to bore it from opposite ends as my inexperience may introduce a screw-up. As it sits in the lathe right now the O.D is perfect, but as it approaches the finished dimensions the wall thickness will drop to 0.028 in., hence the reason I don't want to remove & try setting up again. If I can get the correct length boring bit I can finish out the I.D. and part off the piece I need with everything (hopefully) staying to spec. Thanks.
 

Silverbullet

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#2
You can grind the relief back farther the tools long enough. Boring thin wall If you had a interchangeable carbide or the old style tool bit type deep boring would be no problem. But your doing ok with what you have just grind back the relief .
 

Suzuki4evr

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#3
I agree with silverbullit.
You have enough space on that bit to just grind the relief back,just so you can get the job done.You can make your own tooling later on as you go along. That is if you have the right equipment to do so,and if you don't, that will also come over time. Many of us started that way. You will also learn a lot from the guys on this site. I recon thats why it is here.Good luck 56type
 

56type

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#4
Thanks...I'll grab the dremel and see if I can coax the other 0.100 in out of the bit. Hadn't thought of simply grindeing the shoulder back as I wasn't sure if there was some reason it was ground the way it currently is (i.e. structural integrity of the toll bit as it extended further from the tool holder). Honestly, the next thing on the "to-buy" list will be a bench grinder....
 

T Bredehoft

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#5
Stick a 1/4" end mill in the lantern tool holder, at a slight angle to clear behind the cutting edge.
 

higgite

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#7
OK guys here's where I'm at... I need to make a sleeve to adapt one part to another, and I have the O.D. spot on for a 0.001 in. press fit between the two pieces and have moved to the interior dimension. Interior needs to be bored to 0.661 in. I.D. for a length of 0.998 in. minimum. The O.D of the sleeve is 0.689 in. so the wall thickness will be 0.028 in. when finished.
I'm surprised that no one has pointed out yet that given those dimensions, the wall thickness will be .014", not .028". Hope that's what you wanted.

Tom
 

56type

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#8
I'm surprised that no one has pointed out yet that given those dimensions, the wall thickness will be .014", not .028". Hope that's what you wanted.

Tom
Thanks for pointing that out... When I measured the difference between the two pieces I allowed for a press fit of the parts but neglected to divide the final measurement by 2 for actual wall thickness. Did get it done though, all I need to do is part it off now and try pressing it into place without crushing it. Thanks for all the help...It's been interesting boring a hole with such thin wall thickness for a first time use of a boring tool.
 

4ssss

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#9
If I was doing this I wouldn't try pressing on anything with a .014 wall as it's probably going to crush. You'd be better off heating the sleeve and sliding it on the shaft, as it will shrink itself on tight. If pressing is the way you want to go, then I would have bored it out with a bigger OD and then turned the OD to size as to be concentric with the shaft.
 

56type

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#10
If I was doing this I wouldn't try pressing on anything with a .014 wall as it's probably going to crush. You'd be better off heating the sleeve and sliding it on the shaft, as it will shrink itself on tight. If pressing is the way you want to go, then I would have bored it out with a bigger OD and then turned the OD to size as to be concentric with the shaft.
Got it done...Actually it pressed in quite easily. Got it squared up in the press and once satisfied with it was heading in straight, applied a bit of force with the press along with some lube and it slide together without issue. I was worried it may split with trying to get it on the shaft first so went this route. Now that's it's pressed into the bore I can fixture it when the part is pressed onto the shaft splitting/stretching/deforming it shouldn't be an issue... 1109172234a.jpg
 
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