Tailstock cam lock for mini-lathe.

[zeeprogrammer]

Added a tailstock cam lock for my 7x12 mini-lathe.

This has been done before...and some of you have even made your own...here's another store bought...

For $30 from LMS (way too high in my mind) you get the following...

It's 'easy' enough to install...but naturally I had my 'special' issues.

Started with drilling the hole in back. 1/8,1/4,3/8 to 1/2. Rats. My drill doesn't hold a 1/2. So I mounted it on my cheesy drill press and used the clamping kit from the mill to hold it down. Man what a racket! I had safety glasses on but went to a full face shield when I started having images of bits of drill bit coming at me.

Messy hole. Cam lock shaft still didn't fit. Hit the hole with a file.

Now for the retaining ring. I had been smart enough to get retaining ring pliers but dumb enough to get cheap ones. Didn't fit the clips. Filed the ends of the pliers down and good to go.

Installed the rest of it. Now it was time to test it! Nope. Nothing. Instructions suggest rotating the sleeve. It's better but I don't think it's tight enough.

Well...just like a 'nop' helps in software, or a 'capacitor' helps in electronics...looks like a 'shim' under the sleeve should do the trick.

Also pictured is the original washer that sat under the nut. I think it's obvious I've been over-tightening. I seem to have a bad habit of using too strong a touch. Probably my biggest 'weakness'. :big:

 

[websterz]

I see you are getting past the machine mod phobia nicely Zee. :big:

LMS is a great place for ideas but their shipping charges keep me from buying much stuff from them these days. I go and look at the pictures then make the stuff myself. I just finished my air spring mod a couple of days ago. I found the air spring online for about $14 delivered...the rest I made myself.

 

[rleete]

If you're overtightening that much, you have probably warped or distorted the plate underneath. Try turning it over, so that it's got less clearance. You might also try hammering it flat (it's just a piece of cold rolled), or replacing it with a slightly thicker piece.

 

[Troutsqueezer]

Just curious Z-P, wouldn't it fit in your mini mill for drilling?

It's certainly within your skill set now to have made those pieces. Perhaps you are like me when it comes to making steel tooling; it's a lot harder to machine than brass or aluminum and takes a toll on the cutting equipment so I steer away when feasible.

I've also learned that just a little tighter than snug usually works for my tailstock and same for the drawbar on the mini mill. Took a few sessions to figure that out.

-trout

 

[BobWarfield]

Those camlocks are great, aren't they?

I shamelessly copied that design:

http://www.cnccookbook.com/CCLatheTailLock.htm

Shortly after taking that photo, I bought a keyless chuck. Now my tailstock is wrenchless and keyless. Makes the lathe enormously nicer to use!

Cheers,

BW

 

[zeeprogrammer]

Thanks for looking everyone.

I'd actually bought the kit many months ago and just hadn't gotten around to installing it. Would I make it instead? Well...give me a few more months yet. ;D

Nice tip rleete. Thanks for that.

I did think about the mill first Trout. But no...it doesn't fit. That 1/2" bit is pretty long. Having said that...I just realized I have collets for all the bits I used. Maybe I could have done it when them. The chuck eats up too much Z.

And yeah...I like aluminum and brass fine. Steel scares me. And I don't like cast iron. But I'm hoping it's just a matter of experience and learning. Hope so...as one of my dreams is to build a 3 1/2" gauge locomotive.

 

[shred]

Now y'all need to go slap some calipers down and make some tailstock DROs. Very handy things, those.

 

[mklotz]

For $30 from LMS (way too high in my mind) you get the following...

So, what would you charge to make those parts? Or, put another way, how many of those parts could you make in $30/(your hourly wage) hours?

If you were to make another of Elmer's reversing mill engines for sale, what would you charge?

I'm not trying to get on your case, Zee, but it is important to evaluate price against labor as well as against appearance and mass.

Started with drilling the hole in back. 1/8,1/4,3/8 to 1/2. Rats. My drill doesn't hold a 1/2. So I mounted it on my cheesy drill press and used the clamping kit from the mill to hold it down. Man what a racket! I had safety glasses on but went to a full face shield when I started having images of bits of drill bit coming at me.

Running a 1/2" drill into a 3/8" hole is a sure recipe for chatter - especially until the larger drill is fully bedded in the material. Normal practice is for the pilot drill to be about the size of the larger drill's web, no more. After drilling the pilot, go directly to the final size drill.

Your mill chuck is a 3/8" max capactiy? They make drills with turned-down shanks. I have a set that includes a 7/16 and a 1/2 with a 1/4 (or maybe it's 3/8) shank. Note here that I am *not* talking about S&D (Silver and Deming) drills which are sizes between 1/2 and 1 inch with 1/2" shanks. A set of S&Ds, even cheap import ones, is very useful for efficiently wasting material on big bores on the lathe but, obviously, a 1/2" chuck is required.

 

[Metal Butcher]

Thanks for looking everyone.

I'd actually bought the kit many months ago and just hadn't gotten around to installing it. Would I make it instead? Well...give me a few more months yet. ;D

I made one for my lathe years ago. After about two days of loosening, tightening, and dropping the wrench I had enough. Back when I first got my small 9x20 and M/D there was very little available in terms of accessories and tooling that actually fit.

After you use it for a few days you will regret not installing it the same day it came in. These little conveniences will spoil you, and are worth every penny of their cost. If I had to give up my key-less chucks, I would "chuck" this hobby right quick! :big:

-MB

 

[zeeprogrammer]

Hi Marv,

Certainly, cost of materials isn't the only thing that goes into price...labor, equipment, rent, marketing, sales, etc. Most importantly...what the market will bear. At the time I bought it...my skills were such that $30 didn't seem so bad. Now that I feel I'm capable of making one...$30 is too expensive. I suspect more than one of you said 'What!? $30 bucks!' ;D

Yep. There was chatter going from 3/8 to 1/2. I went 1/8, 1/4, 3/8 and then 1/2. (Per instructions since I don't know better yet.) You say that the step change in size should be no more than the web of the next drill bit. What is web and how do you measure that? (So I'll know better. ;D )

The mill chuck can handle a 1/2" shank...it was my hand drill that couldn't. (LMS suggested a hand drill.) I used my cheesy drill press so I could both clamp the tailstock down and use a larger shank drill bit.

MB...keyless chuck eh? hm....need to build up budget for that...as well as for the drill bits with turned down shanks as Marv suggested....

because....

(Shred is reading my mind)...I'm in the process of making up a bill of materials for a DRO. I'm going to try attaching the calipers first...and then build the display.

 

[mklotz]

Yep. There was chatter going from 3/8 to 1/2. I went 1/8, 1/4, 3/8 and then 1/2. (Per instructions since I don't know better yet.) You say that the step change in size should be no more than the web of the next drill bit. What is web and how do you measure that? (So I'll know better. Grin )

My point was that you shouldn't step drill at all. You drill a pilot hole and then go directly to drilling the final size hole.

The web is that solid section at the center of your drill tip. (Look at a big drill to see it clearly.) The lips of the drill cut; the web doesn't. It just (technical term alert) smooshes metal out of its way. This smooshing makes it difficult for the drill to penetrate. So we drill a pilot hole the size of the web so it doesn't have to smoosh anything out of the way and can expend all its torque cutting metal with the lips of the drill. Pilot drill size isn't anything super-critical. Look at your drill and eyeball it. If in doubt, overestimate (but don't go hog wild).

Aside: Try this sometime when you're bored. Try drilling 1/2" into some steel scrap without a pilot hole and take mental note of the pressure you have to supply on the DP. Now make a 1/8" pilot hole and try the 1/2" drill again. Compare the required pressure to the previous case. I'm betting you'll come away muttering, "Damn, he was right!".

I didn't realize you were using a hand drill. That sounds like a dumb instruction to me.
You want that hole to be relatively straight - not something one is likely to get with a handheld drill. Putting it in the drill press, as you did, was the right thing to do.

McMaster-Carr has 1/4" and 3/8" reduced shank sets

http://www.mcmaster.com/#3135a39/=51mzjd

While I didn't check, they almost certainly will have individual drills with reduced shanks. You only need to buy a few in the range between 3/8 and 1/2 if your hand drill has a 3/8 chuck.

Keyless chucks are sheer heaven. I have a top-of-the-line Albrecht for the mill, bought with some free money that came my way. The import Enco model on my lathe works beautifully and has only marginally more runout than the Albrecht.

 

[cobra428]

Zee,
You can try here too.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=2642

Tony

 

[zeeprogrammer]

Marv,

If I understand you right then...I would have used a #5 center drill and then gone straight to the 1/2"?

I'm surprised about not step drilling though. Seems like I've seen several references to people doing that...at least on the lathe. ???

Thanks again!

And thanks for the link to the drill bits...and also thanks to Tony.

 

[mklotz]

You use a center drill to mark a spot so the "drilling" drill doesn't wander when it starts.

Aside: Technically, even that's wrong. You use a center drill to make center holes on a shaft so you can mount it on centers. You use a spotting drill to make a guide hole to prevent subsequent drill wander. It's a seldom observed distinction.

Then you drill the pilot hole TO FULL DEPTH. This so the 1/2" drill won't have to smoosh anything aside in its journey to the bottom of the hole.

About the only time I step drill is when I'm using a machine that doesn't have the power to horse the final size drill. Even on a well-aligned lathe you'll get some chatter when step drilling. Since I build small things and have a set of S&D drills to 1" and a big lathe motor, I almost never have to step drill. With your (self-described) "cheesy" drill press, you may have had to step drill - although I doubt it.

 

[SignalFailure]

If you're overtightening that much, you have probably warped or distorted the plate underneath. Try turning it over, so that it's got less clearance. You might also try hammering it flat (it's just a piece of cold rolled), or replacing it with a slightly thicker piece.

Been there, done that! My washer was about the same as Zee's but one day the threaded rod parted company from the plate. IMHO the plate was way too thin so I made this chunkier version and silver soldered it to the rod. I also filed a fingertip size depression in the outer end which makes it a breeze to orient the plate properly without looking/rotating it. I don't have the luxury cam-lock yet, just the el cheapo tube extension...the paintwork has taken a little 'spannering' as you can see!

 

[pete]

Zee,
One more thing, If you own a mill then you really need to buy or build a small boring head, Years ago before I bought mine I didn't realise just how usefull these are, Drill with your largest drill bit, Bore to size, Truely round, Straight holes, (Or at least to the limits of your spindle bearings and mill tram) If their not too large for your mill, Grizzly sell a fairly good one from what I've heard, You'd then have a tool that can make an infinite size of holes up to the boring heads maximum size. Imperial,Metric, % of fathoms, Fractions of furlongs, Doesn't matter. All in a tool that fits in your hand. IMO, A mill without a boreing head is only half a mill.

Pete

 

[zeeprogrammer]

Thanks Pete. I got one. I'm looking forward to using it.

 

[pete]

Zee,
First time you use it your going to have a big crap eating grin on your face. One more tip, When getting real close to your final dimension use a .0005 reading dial indicator against the movable slide when makeing adjustments, One division on the dial indicator is a increase of .001 to the bore size. This is way easier and more acurate than reading that tiny little dial on the boring head. Oh yeah, Lock the head slide after adjustments useing only the center allen screw, The outer two are only for adjusting the slide gib when required. If you Goggle "Criterion machine tools" There website should show up, On this, They have some very good info for boreing and useing boreing heads. Required reading IMO. I think you'll find this very usefull.

Pete

 

[cfellows]

Running a 1/2" drill into a 3/8" hole is a sure recipe for chatter - especially until the larger drill is fully bedded in the material. Normal practice is for the pilot drill to be about the size of the larger drill's web, no more. After drilling the pilot, go directly to the final size drill.

Interesting, Marv, I did not know that. I've been using the step drilling process ever since reading about it in the Gingery series of books. I always worried that going directly to the final bit size wouldn't follow the pilot closely enough. I'll have to try it.

Chuck

 

[Maryak]

Interesting, Marv, I did not know that. I've been using the step drilling process ever since reading about it in the Gingery series of books. I always worried that going directly to the final bit size wouldn't follow the pilot closely enough. I'll have to try it.
Chuck

When I was learning this game I was taught to drill a larger sized hole without a pilot hole and no step drilling. There are several riders before this method is adopted.

1. The drill must be accurately sharpened, (you can usually tell this by observing that the swarf is coming off evenly from both flutes in steel).
2. The machine must have the grunt and be rigid enough for the job.
3. The work must be clamped/held rigid to the machine.
4. A taper shank drill is preferred - no drill chuck.

The location of the hole is centre popped and a circle is scribed to the diameter of the hole.
The drill is started and at about 1/3-1/2 of the diameter the drilling is stopped and the circle of the drill compared against the scribed circle.
If the drill is off centre the position of the maximum distance off is noted and then a small round nosed chisel is driven down the taper at this point from the edge of the taper to the centre making a groove, (This will draw the drill/hole towards the groove).
The drill is restarted and the chiseled groove is cut out. The drill is stopped and the observation and grooving is repeated as required.
NB. This can only be carried out whilst the tapered portion of the drill point is on contact with the work, once the drill is drilling to diameter no further corrections are possible.

If a centre drill or spotting drill or pilot drill is slightly off then so will be your big final hole and it's difficult to see when comparing a small diameter drill to a finished large diameter.

Just another way of achieving a better end result. It does work and is worth a try.

Best Regards
Bob