Author Topic: Saddle stop  (Read 6103 times)

Offline Allen Smithee

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Saddle stop
« on: January 24, 2016, 07:33:49 PM »
You know how it is - you're itching to get on with stuff but there's always some piece of tooling that you have to make first. In my case it's a saddle-stop for my Super7. I had one on my previous lathe (30 years ago) and I've felt lost without it. So today I managed to grab some swarf-making time and I decided that this was the opportunity to make one. Being lazy I looked around and found the Harold Hall design and mine is based very heavily on this. I should stress that this is also part of my learning programme, and my reason for doing a thread on such a mundane and simple item is so that those who actually know what they're doing can tell me when I'm doing things the wrong way, or when I'm just being stupid! So comments, jeers etc are all welcome.

HH's design uses a piece of  35x16mm mild steel bar. I didn't have that in my scrap bin, but I did have couple of feet of 60x20mm which I got from the nice lady down the road, so I used that. Not having a decent bandsaw, the required chunk was cut off with a hacksaw after chain drilling.This size bit wouldn't easily go in my Seig X2p, so the chain drilling had to be done in my cheap drill press which could only manage to drill 4mm holes in the steel, which gives a lovely texture:



The resulting block was squared up and one side skimmed smooth in the mill, and then for once I marked out properly. As you can see, a lot of material needed removing!



Chain-drilling was the chosen method, this time in the mill which was quite happy to drill in one go with a 10mm bit (the positions were dimpled with a centre drill, but I rarely bother with pilot holes for this sort of thing) at about 150rpm with a few dabs of supercut in each hole.



A few seconds with a hacksaw and the width of the black was reduces, but it suddenly dawned on me that if I continued with the centre bit the resulting part would be a but flimsy for drilling the holes in the end - I'd have to clamp it to an angle plate or similar, and I'm too lazy to change setups if I can avoid it so I quickly set it up in the vice and drilled the holes - one for an M8 thread and the other drilled 6mm and reamed 1/4" for the guide pin (HH uses a 5mm pin, but I happen to have some 1/4" silver steel rod taken from an old printer, so I'm using that).



I moved it round and rough-milled off the remnants of the chain drilling and then cut the centre clear with a junior hacksaw. This was actually the wrong way around, because I really didn't need to mill off the rough stuff on the part I cut out! ANyway, that gave me this:



I put it back in the vice on a par of taller parallels so that the bottom of the needed cutout was about 2mm above the faces of the jaws. The internal feature was then brought to size with a 16mm end mill, and after a couple of kisses with a file to take some burrs off the result was this, which is within 0.1mm of all target dimensions (that's actually a bit of a first first for me!).



That's as far as I got today as my swarf-making license expired. Things I've learned? My Seig mills steel much better on the X-axis than the Y-axis - probably because of the longer support. It also cuts better running flat out (2500rpm) with a slow feed than at lower revs even with what for this machine is a pretty big cutter, but it needs care (if you look really carefully you might see the graunch where the endmill jumped and grabbed).

Oh yes, and I'f I'd thought about it I should have drilled the hole for the M8 bolt which actually makes the "stop" at the same time as I was doing all that chain-drilling - the DROs were all set up and the quill had the drill chuck fitted, so it would just have been a matter of moving to the right position and changing the drill bit. So next time a little more though about the sequence of events.

What else did I do wrong?

To be continued...

AS
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Offline zeeprogrammer

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Re: Saddle stop
« Reply #1 on: January 24, 2016, 07:46:30 PM »
and my reason for doing a thread on such a mundane and simple item

Not really. As far as I know, such items don't usually come with a lathe.
This is the kind of thing that's very helpful to newbies.

I've found mine indispensable.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline PStechPaul

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Re: Saddle stop
« Reply #2 on: January 25, 2016, 07:17:12 AM »
I should make something like that for my lathe. I did make a cross-slide stop:
 


 

 
I was able to mill out a similar shape to your saddle stop using my small round column mill:
 
<a href="https://www.youtube.com/watch?v=Zj8gMvKR57M" target="_blank">http://www.youtube.com/watch?v=Zj8gMvKR57M</a>

Offline chris evans

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Re: Saddle stop
« Reply #3 on: January 26, 2016, 08:06:43 PM »
I like the idea of the cross slide stop, never seen one before.

Offline mklotz

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Re: Saddle stop
« Reply #4 on: January 26, 2016, 09:23:04 PM »
I like the idea of the cross slide stop, never seen one before.

Makes single-pointing threads a lot easier.
Regards, Marv
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Offline propforward

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Re: Saddle stop
« Reply #5 on: January 26, 2016, 09:45:48 PM »
I'll be making one of those.  :ThumbsUp:
Stuart

Forging ahead regardless.

Offline Allen Smithee

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Re: Saddle stop
« Reply #6 on: January 26, 2016, 10:37:09 PM »
So no one noticed the glaring mistake then?

 :facepalm:

AS
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Offline propforward

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Re: Saddle stop
« Reply #7 on: January 27, 2016, 12:45:29 AM »
I'm not seeing what it is  :shrug:

But I'm a novice. Frankly I think this is a great thread - I  already learned some good stuff from it.   ;D
Stuart

Forging ahead regardless.

Offline b.lindsey

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Re: Saddle stop
« Reply #8 on: January 27, 2016, 12:48:16 AM »
How are you going to mount it to the lathe bed?

Bill

Offline Brian Rupnow

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Re: Saddle stop
« Reply #9 on: January 27, 2016, 01:14:44 AM »
Paul--I like the cross-feed stop. I had one on my old lathe, but it wasn't really easy to install/remove, and it sat on top of the cross-slide and was always full of chips. Your version is very much adaptable to my new lathe. Thank you for posting it.---Brian

Offline Allen Smithee

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Re: Saddle stop
« Reply #10 on: January 27, 2016, 08:25:49 AM »
This picture should have the title "what happened next?":



 :-[ :ROFL:

AS
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Offline Allen Smithee

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Re: Saddle stop
« Reply #11 on: January 27, 2016, 08:29:39 AM »
How are you going to mount it to the lathe bed?

Like this:



I gave a link to the drawing in the OP, but it looks like the attached

AS
« Last Edit: January 27, 2016, 10:42:36 AM by Allen Smithee »
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Offline Jo

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Re: Saddle stop
« Reply #12 on: January 27, 2016, 08:39:44 AM »
This picture should have the title "what happened next?":

It is all a learning experience  ::)

Jo
Enjoyment is more important than achievement.

Offline Allen Smithee

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Re: Saddle stop
« Reply #13 on: January 27, 2016, 08:49:29 AM »
As my flying instructor would recite at the slightest provocation:

Wisdom comes from experience. Experience means learning from mistakes. The best kind of mistakes to learn from are those made my other people...

Another of his pet sayings which has always stayed with me was:

"The superior pilot uses his superior judgement to plan, and thus avoid the need to use his superior skills"

AS
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Offline PStechPaul

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Re: Saddle stop
« Reply #14 on: January 27, 2016, 10:40:39 AM »
Well, what did happen next? Apparently you, the piece, and the machine survived. My guess is that the drill bit jammed and stalled the mill spindle. That technique might work OK if you put some pieces of rod or tight-fitting screws in a couple of holes before drilling the last one.  :old: ;D

Offline Allen Smithee

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Re: Saddle stop
« Reply #15 on: January 27, 2016, 10:46:57 AM »
No, it drilled fine. I drilled the next (final) hole which also had no problems, but as I raised the drill back up I noticed that the work was lifting smoothly out of the vice, so I quickly hit the stop button!

I have a mental image akin to this:



Note to self - next time I chain-drill remember not to clamp the work across the line of holes I'll be drilling!

AS
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Offline Allen Smithee

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Re: Saddle stop
« Reply #16 on: March 29, 2016, 11:59:04 PM »
In case anyone was wondering what happened here, and to show that I do sometimes actually finish things, this is what the finished item came out like:



And here it is actually being useful:



I do have some photos of the piece-parts before it was finished if anyone is interested. I intend to replace that M8 bolt with something that has either a tommy bar or even a ball-handle, because I hate having to use spanners for things like this.

AS
Quidquid latine dictum sit altum sonatur

 

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