GH600 tapered gib

[Lee KennedyParticipant @leekennedy29914]

Good afternoon,

Hope everyone is doing well.

I recently had an incident with my GH600 and as a result I have broken the cross slide tapered gib.
My plan was to contact warco, but I’m sure I read elsewhere that they would supply a piece of stock I would have to machine.
So I’m looking for advice to tackle this.
my plan was to try and shim the stock on mill bed to get close then commence with scraping.

Does anyone have any experience making tapered gibs?
Lathe is out of action now so I’m keen to resolve quickly.

thanks in advance.

Lee

[DiogenesParticipant @diogenes]

I think that sounds okay, there’s probably scope for a bit of filing/draw-filing or even lapping on a sheet of abr. paper stuck to a flat surface – as you know the OEM item isn’t exactly ‘best Swiss quality’ in terms of finish.

The thing to watch during the milling op. is that the blank is properly supported so that it doesn’t come out ‘barrelled’ due to flexure under the cutter – i.e. I’d stick the blank on a plate, and then shim that, rather than just shim under one end of the blank itself..

..what material do you have in mind? ..I have some vague suspicion that the one in mine is CI..?

[Lee KennedyParticipant @leekennedy29914]

The original is cast iron, and the lathe has always been accurate, but yes when you have it in your hand the finish on the original doesn’t scream quality.

Yeah my plan was to stick the new gib to a longer piece of stock and clamp that to mill bed.
I would use CI again if I can find some suitable material. Failing that a bronze. I have seen videos since researching this of people having success with brass.

Annoyingly this is 100% my doing so hopefully I’ll avoid the same mistake again.

[Pete RimmerParticipant @peterimmer30576]

Measure the taper on your gib you should find it to be 1:100. If you have a surface grinder you can achieve this angle by putting a piece of metal under one end of the mag chuck. On mine I use an ally tig welding rod.

Check the angle by traversing the table 100mm and observing a rise of 1mm on a dial gauge mounted vertically above the chuck. Move the packing piece until you achieve the correct taper and then secure the chuck.

When you grind the gib you’ll have to keep flipping it as the grinding will caused it to bend. Correct any small bend at the end by setting the gib down on a surface plate to check for dish and they peening the concave side gently along its length with a small ball pein hammer.

Grind or file the thin edges for the correct angle after you have done the taper.

 

 

[Lee KennedyParticipant @leekennedy29914]

Hi Pete,

 

thanks for reply.
unfortunately I don’t have a surface grinder yet so I’ll have to do this on mill.

Looking at the original, I think it should be achievable to do.

 

[Pete RimmerParticipant @peterimmer30576]

Measure the taper and dimensions and I’ll see if I can knock one up for you,  or if you’re in Kent you could pop round and use my workshop

[peak4Participant @peak4]

Stefan Gotteswinter produced quite a good video which I found whilst I was chilling out due to Covid the first time around.

I later did something similar myself, but I’m fortunate enough to have access to a sine table, which pivots about the long axis. I used this on the Centec mill, but have also fitted it to the Dore Westbury.
Because of the way the slots run, I was able to use a row of horizontal clamps, rather than crab clamps; they work in a similar fashion to the machine vices he was using, but are just a single moving jaw, which you can bolt down to a T slot.

For the long taper, I can either use a tilted magnetic table; I had one which came with the surface grinder, which I could use whilst it was out of commission.
It works fine with the Centec, but is prone to holding the chips against the workpiece which scratches it as they get caught by the end mill.
That can either be jacked up at one end, or fitted to a long tilting table which pivots about the short axis; it’s not a sine table, and doesn’t have any degree scales, but can be set with a sine bar as depicted in Stefan’s video.
One day I must take some measurements and add a piece of bar under the moving part to make it into a short axis sine table.

Bill

 

[Lee KennedyParticipant @leekennedy29914]

Thanks Pete, I’ll measure up and see what your thoughts are.

[Lee KennedyParticipant @leekennedy29914]

That looks like an interesting job

[Pete RimmerParticipant @peterimmer30576]

Here’s a post of me grinding tapered cast iron gibs for my milling machine rebuild for turcite.

 

Tapered gib grinding

[Lee KennedyParticipant @leekennedy29914]

Very familiar with your work from the mig forum.
I had no idea until now it was the same person.
awesome stuff

[Pete Rimmer]

On Pete Rimmer Said:

Here’s a post of me grinding tapered cast iron gibs for my milling machine rebuild for turcite.

 

Tapered gib grinding

A couple of mine came out too thin; the plain parallel one I just made a thicker replacement for the table traverse, largely what is depicted in the above photo.
The tapered gib on vertical part of the knee, I used some self adhesive Tribo Tape; it remains to be seen how long the glue lasts. That gib is only used for changing the height or depth of grind, rather than continuous back and forth.

https://www.igus.co.uk/product/iglidur_T_B160?artnr=B160-T-005-0020-G

Bill

[Robert ButlerParticipant @robertbutler92161]

Lee

Warco website “Handbooks” has the GH600 listed with a parts list. Looks to be referred to as “panel” but has maybe lost something in the translation but having two screws one at each end is probably the tapered jib strip. Worth a phone call to see if available and I would guess ready to fit given the difficulty in preparing a tapered gib from a blank in the normal home workshop.

Robert Butler

[Lee KennedyParticipant @leekennedy29914]

Thanks Robert

[DiogenesParticipant @diogenes]

Thanks Pete Rimmer – a good read..

[Lee KennedyParticipant @leekennedy29914]

Evening all,

Pete was a real gentleman and knocked a new gib up for me.
He has a quick write up on it over on mig forum but he may well post it over here at some point.

very happy with the result, I’ll give it a scrape for best fit but it’s very good as it is. I’m back up and running.

thanks to Pete

[Pete RimmerParticipant @peterimmer30576]

Thanks Lee I had a lot of fun making that gib and several firsts for me. First tapered gib from scratch, first time using a horizontal mill (or making any part on my TOS mill since I rebuilt it). Ironically the easy part was making the 1:100  tapered faces it was milling the 55 degree bevels afterwards that gave me trouble.

For anyone who is interested I did a write-up here which you can read without logging in:

Making a tapered gib

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