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South Bend 7" Ram Problem

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Pete301

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#1
I could use some help with a problem I found on my SB shaper. If i put a pry bar under the ram while it is partially extended i can lift the ram upwards and i can see the movement at the dovetail! If I pry on the left side of the ram the movement is about .012
1 (1).jpg
and on the right side it's about .008.
So i took the ram off the shaper. Cleaned the dovetails, inspected for burs, chips etc. Ram and column both looked ok. No scoring or obvious issues. The gib is straight, not bowed or bent and without burs.I put it all back together and adjusted the gib, but i can not get the ram to travel freely and not lift up. If I tighten the gib i can stop the upward movement but then the ram won't travel freely ( or i can get the ram to travel freely, but then the ram can move upward again). I had a spare ram so I tried that one with just about the same results.
So, is my shaper a basket case? Just worn out? Should I be checking something else out? Could the column dovetail be worn down enough to cause this?

1 (2).jpg
 

Clock work

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#2
Is that dovetail on the ram painted? It does look it... if so, I'd think we found your problem.

CW
 

markba633csi

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#3
I would think the gib would wear more than the dovetails but maybe I'm wrong about that. Perhaps you just need a better fitting gib?
Mark
 

francist

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#4
I have no doubt that you will find some upward movement in the ram at extension, but before getting too hung on that I would suggest a better setup with your indicator. It's going to be very difficult for you to get meaningful measurements with the indicator cocked in at an angle like that. The stem should be perpendicular to the surface being measured, not angled off on the side of the tip.

I can appreciate it's tough to get the indicator underneath the ram, but it also does not have to be underneath to measure the upward moment. Maybe stick your mag base to side of the ram casting with the indicator tip pointing straight down and pressing against the nice flat running surface of the cross rail there. You will still be measuring upward movement of the ram relative to the table, but your measurements will be much more realistic and repeatable.

-frank
 

cjtoombs

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#5
I would think you could take care of your clearance issue by adjusting the gibs.
 

Silverbullet

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#6
Ok why are you lifting the ram. Did it not cut right ? If it's not hopping or cutting choppy I think your expectations of the shaper are to high. Take a few minutes and watch the backyard machinist he's rebuilding an ancient model shaper , he micrometer cked both sides and to clean it up he took about .008 off to square up his . Yours may need the ram cked on a surface plate I don't know I just wonder why or how you started pushing it up to Ck it out . I'd worry more of sideways while in the DOVETAIL not sticking out over the vise. If you pull on a Bridgeport spindle when hanging I bet it will move that much too. Somehow it don't seem the thing to do. No I'm not judging or being mean just trying to see if it's really messed up.
 

Dabbler

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#7
Some movement upward in the ram of a shaper is expected, especially in an older machine.

Some questions about how it performs: Does it cut straight, or does it cut a small angle (upwards) as the ram extends? Is your surface finish showing chatter? (or ripples in the finish every 1/8" to 1/4")

If the above questions get a yes answer, then there is some work to do on the ram and gibs, but if it cuts well, then, it might be better to use it as is.
 

Pete301

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#8
Some movement upward in the ram of a shaper is expected, especially in an older machine.

Some questions about how it performs: Does it cut straight, or does it cut a small angle (upwards) as the ram extends? Is your surface finish showing chatter? (or ripples in the finish every 1/8" to 1/4")

If the above questions get a yes answer, then there is some work to do on the ram and gibs, but if it cuts well, then, it might be better to use it as is.
Oops, I got behind in responding to this thread- sorry. To answer some of the previous questions. No that isn’t paint on the ram dovetails and no amount of gib adjusment will fix this problem. It’s either binds up or you get loose as a goose!
So the problem I’m having is that it is cutting a taper. Thick end away from the machine. I have a ongoing job for a hydraulic component. Workpiece is 1.750 wide,.750 thick and 5” long. CR 1018. I use the shaper to make the two wide sides (1.750) parallel and smooth. Thickness of the part doesn’t matter much but the two sides do need to be parallel within 1/2 thousandth. I have a Atlas shaper and it can spit these parts off all day at that variance. The South Bend can’t stay within 5 thousandths for the same job, using the same bit and vise set up. Because it’s cutting a taper I got to checking things. I put a DI in the ram tool holder and measured the vise ways. As I extend the ram and move the table down the vise ways the DI stays at 0. I took the vise off the table and check the table top also-same thing the DI hardly moves. So that lead me to think the ram might be the issue and when I saw the large amount of lift I figured it was the problem even tho I don’t want to believe it!
 

Dabbler

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#9
The next step would be to measure your ram and ways for straightness. It is possible that your ram (ways) have worn into a curve... that would take some effort to fix, however...
 

Pete301

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#10
I did measure the dovetail in the column and it was .003 bigger in width at the front ( by table end). The bottom of the dovetail ( the horizontal part) was .002 lower in the rear non gib end. I have a surface plate so I could measure part of the ram dovetail (its horizontal part) but I don’t think I can measure the rams dovetail. I can’t figure what I could reference from. And in any event I don’t think I can fix it myself and I doubt I could afford to have it done. I hate to admit it but I my have to junk it and part out the useable stuff. Just doesn’t feel right tho.
 

Dabbler

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#11
--It is a shame. Some companies will do discount work for hobbyists if time is not pressing, and you could then get the ram surface ground to straighten it, but that would still be in the (small) hundreds of dollars. I wish you were closer to Calgary, we could have a go at fixing it!
 

Pete301

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#12
Thank you for the help and support. I don’t know about the shaper’s past history and use, but I’m nevertheless surprised ( and sad) that the dovetails wore out. Funny how you can get so attached to an old machine.
 

Dabbler

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#13
I'm attached to all my old machines!
 

tertiaryjim

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#14
The dovetails are worn but not worn out.
If you don't have the machine capacity for the job it could still be scraped in. lots more time involved but will not only save the shaper but will have it cutting to very close tolerance. With the measurements I've taken on old machines I've learned that many left the factory with very poor tolerances and even an amature scraping job cam make them run better than factory new.
Perhaps you could also sell it whole and get your money out of it.
 

jwmay

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#15
There’s an article on the NEMES website where a person recut his shaper ram dovetail ways on a milling machine. It’d be worth reading. He didn’t express anything about the job being especially difficult. I can’t remember if he scraped it afterward. I do think he made a new gib strip. Anyhow, New England model engineer society I think...check it out. I’m not a member, but there’s good info there about this.
 
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