RF30 Basement Install

[YYCHM]

Double washers were the ticket for me.
A single washer just made me pull my hair out.

Craig, is that a 6” vise?

5".

After 4 hours of getting some very confused measurement results @Dabbler finally figured out the cause of all my problems. Ends up there is sufficient play in the x-axis Gibb that the table moves as you're trying to square the vise. John will be able to explain it better than I. Until we come up with a plan as to how to resolve that issue I'm going to have to live with vise not being as square as it should be.

Thanks for all of your help with this John.

Craig

 

[DavidR8]

5".

After 4 hours of getting some very confused measurement results @Dabbler finally figured out the cause of all my problems. Ends up there is sufficient play in the x-axis Gibb that the table moves as you're trying to square the vise. John will be able to explain it better than I. Until we come up with a plan as to how to resolve that issue I'm going to have to live with vise not being as square as it should be.

Thanks for all of your help with this John.

Craig

Wait... the same axis that gave you and John fits?
ARGH!

 

[YYCHM]

Wait... the same axis that gave you and John fits?
ARGH!

Yup, the same axis that gave us the Gibb installation grief.

What issue did double washers resolve in terms of setting up your vise?

 

[DavidR8]

Hereafter known as "The Great Gibb Incident of 2020"

 

[Dabbler]

The symptom is that when the X and Y gibbs are completely locked and there is still freedom for the table to move (rotating around the Z axis, if that makes sense). Just a few thousandths, but enough that rotating the X axis hand wheel yields inconsistent results. Makes lining up the fixed jaw really hard.

Also the holes in the vise need to be drilled out a little bigger, to allow appropriate alignment.

@David_R8 You might try making your own washers on your lathe I made mine, and a set for Janger - .200 thick, with beveled top edges.

 

[Brent H]

Do you need a better Gib Craig? What are the dimensions of your current ones.? I have a couple cast iron gibs from another machine that could be machined if they fit the bill??

 

[YYCHM]

Do you need a better Gib Craig? What are the dimensions of your current ones.? I have a couple cast iron gibs from another machine that could be machined if they fit the bill??

I'll let @Dabbler comment on that. The situation is a little complicated. We would have to pull the Gibb and figure out how to measure it.

Craig

 

[Brent H]

Basically need the length and the height and the thickness of either end. I believe the pair I Have are about 12 to 14” long each not sure on other dimension. I have some other cast iron longer - if yours is 30° bevel or?

 

[YYCHM]

Basically need the length and the height and the thickness of either end. I believe the pair I Have are about 12 to 14” long each not sure on other dimension. I have some other cast iron longer - if yours is 30° bevel or?

It's close to 15" long and tapered both front and back along the flat and tapered in height. 30 deg bevel? Are you talking the dove tail angle? The dove tail angle is 30 deg.

 

[Brent H]

Roger that @YYCHobbyMachinist - home in a week or so - if things are still an issue I will measure things up and see what I could send you if you require assistance.

 

[YYCHM]

Roger that @YYCHobbyMachinist - home in a week or so - if things are still an issue I will measure things up and see what I could send you if you require assistance.

Thanks Brent!

 

[Dabbler]

We partially measured the X gibb, but the key will be the gibb angle, and if it is rounded or actually flat. I've kinda burnt out of this project and have to devote time to the other 30 things on the go....

Still have one thing to move up Bert's stairs, and complete the reassembly of the 15" lathe, to name but 2.

 

[YYCHM]

Man after 3-4 hours tonight I had that vise down to 0.001 over 4.5". That's less than I can twist the table. Tighten down the loose bolt and she kicked over. Back to 0.02. This is getting tedious. I'll drill the bolt holes bigger once I have a proper clamping kit, which is tomorrows project.

 

[historicalarms]

Are there not 'set screws" threaded into the table to set the gib resistance that sets how much effort it takes to transverse the table (not the locking screws, they are a separate item), this should also remove any excess dovetail slop to your movement. I'm not in the shop at present and its Been a while since I had the table off mine but I seem to remember some grub screws for setting the slack used in conjunction with the "end screw" that catches the slot in the gib .

Craig, the reality of these inexpensive off-shore machines is that tolerances attained (precision ground) in the much more expensive machines may never be attained ...no harm in trying to see how good you can actually get it but it could drive you to distraction looking for the unattainable. My experience with my machine is that a .001 trammel is very hard to attain within my usual time frame of "smoke from my ears" frustration....0005 is just a fluke of monumental fortunate proportions.

JohnWa, I can commiserate with you on your rotary vice base, until, to alleviate my frustrations and not make me so reticent to use the angle options of my rotary capable vice, I made it easily returnable to a 0-0 trammel as I could within the limitations of both vice & table.

 

[YYCHM]

Are there not 'set screws" threaded into the table to set the gib resistance that sets how much effort it takes to transverse the table (not the locking screws, they are a separate item), this should also remove any excess dovetail slop to your movement. I'm not in the shop at present and its Been a while since I had the table off mine but I seem to remember some grub screws for setting the slack used in conjunction with the "end screw" that catches the slot in the gib .

Craig, the reality of these inexpensive off-shore machines is that tolerances attained (precision ground) in the much more expensive machines may never be attained ...no harm in trying to see how good you can actually get it but it could drive you to distraction looking for the unattainable. My experience with my machine is that a .001 trammel is very hard to attain within my usual time frame of "smoke from my ears" frustration....0005 is just a fluke of monumental fortunate proportions.

JohnWa, I can commiserate with you on your rotary vice base, until, to alleviate my frustrations and not make me so reticent to use the angle options of my rotary capable vice, I made it easily returnable to a 0-0 trammel as I could within the limitations of both vice & table.

No set screws, only the Gibb adjustment screw and the table lock screws.

To date all's I've ever done to align a vise to the table was use a machinists square. This tramming exercise is a real eye opener for me.

Ya, I know she's no 6000# Bridgeport.

Craig

 

[historicalarms]

first of all, I don't agree that a 150-$ 200 Kurtz type clone is unusable junk, I quite happily use mine most every day I'm in the shop. It does have a .0005 lift to the movable jaw when tightening but that is well within the tolerances of anything I have had to do so far. Not sure how much lift an OEM Kurtz will have, but moveabilty tolerances would require a bit but closer manufacturing tolerances should be tighter for that kind of money difference. Strength-wise & rigidity, I cant see $50 difference let alone many hundreds.

I brought the re-positioning timeline to a more acceptable level in my BB purchased Kurtz clone with a couple easy mods.
first of all you want to attach a square steel bar to the rotator base of your vice as close as square as you can get between the bolt-down lugs of the base. This bar must be a tight "friction fit" to the T-Slot openings in your table (mine was .625 exactly and requires a bit of a "pry" to remove from the slots)). this bar does not need to be a 0-0 trammel to the bolt lockdowns but as close as you can easily get it.

Now inspect the base for the meatiest part of the frame, you will need to know where this is shortly.

Now install the vise to your table and lock the base down, leave the top of vise to rotate as needed to trammel the stationary jaw as close to ") as you can get...disregaurd the deg. markings on the base as they are pretty much meaningless, now lock that to the base with the top locking bolts.
Now, (mine is drilled as close to the top locking bolts as I could get without interfering with their operation) at the meatiest spot in rotational part of the frame of the top of the 1/2 of the vice that also hits a meaty part of the base casting, drill a straight true, hole through both halves ( I used 1/4 inch in mine). Now insert a 1/4" bolt shank with the threads cut off into the hole...do the same on the other side of the vise jaw, again as close to the lock-down bolt as you can get...insert another bolt. The proper way to do this if you have the equipment & hardware available is to ream a tapered hole to co-inside fit with a tapered pin...

Now I can remove the pins, unlock the top bolts, turn to any angle I desire for a cut & once finished be back to pretty much a "0" tramel within the tolerances of my machinery within 30 seconds.

 

[Dabbler]

@historicalarms I agree that clones can be very good - stronger than a typical hobby requirement. I jsut sold my BB/Taiwanese 5" vise, keeping 3 clones and a genuine Kurt. The kurt has some nice features, but it is a luxury, and the similar clone preforms just as well.

As in any endevour, there are differing points of view... I have one vise that is keyed and all the others are not. My big vises do not have rotating bases or keys, and I have no plans to add them. They live off centre on the table for years before moving them. Tramming them once per year is no big deal, even if it takes a little effort.

 

[YYCHM]

A big part of this vise mounting problem was that there was never enough wiggle room between the t-nuts, bolts and vise mounting holes to get her square in the first place. This was just confusing me and John concluded this situation Monday for me.



So today, with my new to me 1/2" clamping kit on hand (@thriller007 and I traded kits, thanks Bill) I drilled the 1/2" vise mounting holes out to 9/16". Hmmm..... drilling cast iron is way less dramatic than steel, aluminum or brass.



Being a little fed up with tramming, I decided to rig this up and square her to the back edge of the table. That chunk of steel that is clamped down is the steady rest riser that came with my lathe. My machinist squares tell me it's as square as my squares, so as good a thing to use as anything else I have.

Using this arrangement proved that there still wasn't enough wiggle room to square it up. So I tore it all down and drilled the vise mounting holes to 5/8". Set everything back up, and now we are getting somewhere. I can square the fixed jaw to the back edge of that table using a machinist square.

So, thinks I, I wonder what tramming will tell me now. I got 0.005 over 4.5". I then got her down to 0.003 by loosening the bolts and bumping the vise over. I can physically twist the table over 0.003 so I stopped there.

Phew... what a wild goose chaise.

 

[YYCHM]

Roger that @YYCHobbyMachinist - home in a week or so - if things are still an issue I will measure things up and see what I could send you if you require assistance.

Brent, here is a crude sketch showing the dims of the ends of the Gibb as measured in place.



That washed out number on the thick end is 0.822. I question the 0.913 measurement as the thin end isn't sticking out of the dove tail to get the caliper on. As to being tapered in 1, 2 or 3 dimensions is beyond me.

Anyways this should give you an idea as to what it looks like and something to think about.

I'm not planning to pull the Gibb until I install my DRO which is weeks away unless I can't stand how the machine is performing.

Thanks,

Craig

 

[trlvn]

... I can physically twist the table over 0.003 ...

I'm having trouble getting my head around this. This gib is _far_ from doing what it is supposed to.

If I've followed correctly, you had huge problems reassembling the table because the gib needed to be positioned above the bottom of the space it fits into. Now that it is reassembled, one end (I take it) must not be fully filling the space it is supposed to fill.

Because you can twist the table, this sounds to me like the gib is undersized at one end--in other words, not the correct taper [1]. In fact the reassembly problem suggests it is not the right size in another dimension.

Makes me think that the gib really does not go with your machine at all. OTOH, I imagine it would be extremely difficult to purchase a better replacement.

Making a better replacement is not trivial, either. Since the existing gib is the problem, you need some really precise measurements of the space that the gib is supposed to fill. And then some awfully precise machining (scraping?) of the new part. Almost certainly has to be surface ground for precision.

Keith Rucker (Vintage Machinery on Youtube) has done new gibs a couple of times:

https://duckduckgo.com/?t=ffab&q=keith+rucker+machining+a+gib&ia=videos

Craig

[1] Can you put a dial indicator on the machine base and measure how much the table will move (twist) at either end. That should confirm if the gib is too small at just one end. And tell you how much too small.