Author Topic: Seig X2p improvement  (Read 4165 times)

Online Allen Smithee

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Seig X2p improvement
« on: October 10, 2015, 11:52:47 AM »
As I've mentioned before, I have a Seign X2p which I bought second-hand with a known "issue" that the X-axis gib could only be set for smooth & slop-free movement over narrow ranges of table travel, and even then it wasn't as smooth as I'd like. But the price reflected this and I was quite happy with it for most of what I was doing at the time.

But it became more of a niggle as time went by, so eventually I took it over to our local guru (Eric - "The Muddled Engineer") to see if he could sort it out. I was assuming that the dovetails were either not parallel or just not straight, and so I asked Eric if he could treat it as a raw casting and cut the dovetails properly(!). Eric looked into it and discovered that the problem was actually much simpler than this - the dovetails were straight and parallel, but the undercut below the dovetail was too shallow for the gib as in the simplified sketch below:



This meant that the gib was riding on three corners of the castings rather than the machined faces, so of course it was impossible to find a single setting that worked and was never going to be smooth. Eric simply cut it a little deeper (the picture exaggerates - I don't think much material had to come off) so that it all sat properly:



It's now as smooth as a smooth thing - not in a hardinge/schaublin class of course, but much MUCH better than it was and ithas the same feel from one end of the table travel to the other. Eric naturally machined this in a decent mill, but it doesn't actually need precision because it's just creating space and none of the dimensions are critical. It could have been done with a file or a dremel (or if you're a real butcher even a large hacksaw!).

So if you have a machine from the X2 family whose gibs never seem to set nicely it might be worth seeing if you have this issue as well because the effort required to stop having to live with it is not excessive.

The downside is that one of the main items on my list of excuses for not getting on with things has now been deleted...

AS
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Offline Jo

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Re: Seig X2p improvement
« Reply #1 on: October 10, 2015, 12:35:43 PM »
 :whoohoo: Nice to hear it is all fixed.

So are we going to see some swarf soon  :mischief:

Jo
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Offline Jasonb

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Re: Seig X2p improvement
« Reply #2 on: October 10, 2015, 05:14:41 PM »
Would it also have been possible to take a bit off the gib strip as that may be easier for people than altering the casting.

Online Allen Smithee

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Re: Seig X2p improvement
« Reply #3 on: October 10, 2015, 05:23:41 PM »
Would it also have been possible to take a bit off the gib strip as that may be easier for people than altering the casting.

Probably, but the gib is small enough as it is! I'd be nervous about distorting it as I don't have a vice wide enough to hold the whole length - I would have had to make a fixture to support it while milling/filing it. But yes, that approach would probably be as good. A spare gib is under two quid, so I guess you could afford to have several goes at it!

AS
« Last Edit: October 10, 2015, 05:28:04 PM by Allen Smithee »
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Offline Jo

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Re: Seig X2p improvement
« Reply #4 on: October 10, 2015, 05:40:00 PM »
I got told off when I suggested that solution to Eric :-[

He had a good reason why it was not a good way forward but  :shrug: can I remember  :ShakeHead:

Jo
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Offline Jasonb

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Re: Seig X2p improvement
« Reply #5 on: October 10, 2015, 05:42:30 PM »
I just thought of it as you see a lot of gibs that are parallelogram shaped rather than rectangular.

Online sco

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Re: Seig X2p improvement
« Reply #6 on: October 10, 2015, 07:02:45 PM »
Glad to hear that it was a relatively simple fix!  Isn't it time you made something with it  :stickpoke:

Simon.
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Online Allen Smithee

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Re: Seig X2p improvement
« Reply #7 on: October 10, 2015, 07:14:31 PM »
Glad to hear that it was a relatively simple fix!  Isn't it time you made something with it  :stickpoke:

Indeed. I've had an approach from Red Bull - I gather they're a little desperate to find someone who will make engines for them...

 :mischief:

AS
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Offline Jasonb

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Re: Seig X2p improvement
« Reply #8 on: October 10, 2015, 08:04:52 PM »
Pete, I'm sure Red Bull would love your engines, just don't use the same timing belt supplier that Sieg use.

This one went tonight, not bad for 6yrs hard work. I will have to start calling my mill Mr Fluffy :Lol:




Online Steamer5

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Re: Seig X2p improvement
« Reply #9 on: October 11, 2015, 01:40:15 AM »
Hi Jason,
6 years use at the amount of work you put it thru I'd say wasn't bad!  :stir:

At the last place I worked we had a belt on an over head cooling fan giving issues. The maintanence guys replaced it & brought the old belt to the control room, " don't know what's wrong with you guys this is as good as new" was the comment, he then turned it the other way up & almost every tooth had come off one side....

Cheers Kerrin
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Offline Pigi

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Re: Seig X2p improvement
« Reply #10 on: October 16, 2015, 11:15:05 AM »
Allen,
 here are 3 shot from my X2P axis gibs:

These looks quite different from your drawing, and shows quite well where the problem is.

I'm still searching a way to solve the problem.


Can you please take a shot from your fix ?

Thx

Pigi

Online Allen Smithee

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Re: Seig X2p improvement
« Reply #11 on: October 16, 2015, 06:34:24 PM »
Isn't it time you made something with it  :stickpoke:

As it happens I have to make a couple of these assemblies as an urgent job for a friend. Should be a good practice exercise (as well as being a useful "remembering how to use Solidworks" one!).The bits are steel, ant for scale the main bore in the trunion is 11.9mm dia.

AS
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Online Allen Smithee

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Re: Seig X2p improvement
« Reply #12 on: October 16, 2015, 06:40:19 PM »
Pigi - my modification was to the X-axis (left-right). Your photos are of the Y-axis (forward/backwards). But a similar mod could work by machining a clearance groove at the top or bottom of the dovetail so that the gib can sit flat on the faces. Or you could try skimming the gib itself, but that needs precision and careful fixturing to ensure the edges remain parallel and smooth/straight.

AS
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Online Allen Smithee

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Re: Seig X2p improvement
« Reply #13 on: October 17, 2015, 01:36:42 PM »
...and I've finally made some swarf with it - squaring/facing-up a bit of hot-rolled steel rectangular bar to make those trunions. And I can confirm that it is now MUCH better than it used to be. The action is smoother, and when taling a 0.5mm facing cut with a 12mm end mill I can run right->left and then left->right for the next cut and there is no visible or finger-detectable edge between the up-milled bit and the down-milled bit. This was definitely NOT true before. I ran the cutter at 2500rpm and the surface finish is nice - you can see milling marks, but can't feel them. Again, this was not true before.

So I'm very happy, and making time for starting the next proper project...

AS
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Offline Pigi

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Re: Seig X2p improvement
« Reply #14 on: October 19, 2015, 07:26:01 AM »
Allen, 
 please please please, post some photos from this modification....

I'm really interessed  :Love:  in seeing how it's made .


Pigi