Harig 612 - roller ways damaged during transportation

[Wiktor]

First of all - greetings from Poland!

I just recently bought a surface grinder made in U.S.A - Harig 612. Unfortunately, due to my lack of experience and knowledge, I did not properly secure the table for transportation and the table slipped of the machine. Luckily, I did not loose it. But a few rollers from linear roller bearing are damaged (below there is picture of similar setup). After swift period of grief, I'm looking into my options what to do with it. I tried to find replacement bearing or just the rollers but no luck here. I also find some posts here on the forum stating that people have these machines without rollers at all (also the manual does not seem to mention that part). I would very appreciate any advice how to tuckle this problem.

 

[michiganbuck]

Welcome to PM Wiktor.

Can you accurately measure a rollers and note any features?
Likely to make them you might like to add centers, although a dedture or centerless grind shop can make the without centers. If mine I would like them done between centers.

I would measure all the rollers to 25 millionths, and consider how you want to put them back...then selectively place them back. I am roughly thinking in a way that puts the largest at the ends tapering to small at the center.

You might find dowels or some other roller material source. One fellow I knew made such from CRS...likely originals were tempered.

Almost all the PM threads suggest locking the table any time you move a grinder, even if just around the shop...but done is done and I have also made mistakes moving machines.

 

[Peter from Holland]

I would sugjest to buy some needle roller linear cages
Like these
Or if you have more time as money make some from dowel pins Perhaps sorted to diameter (how good is the machine???)
and then have 3 cages made by waterjet out of brass or machine them yourself
Then some burs with a chissel to keep the pins captured in the slots but free to roll

Peter

 

[Wiktor]

Welcome to PM Wiktor.

Can you accurately measure a rollers and note any features?
Likely to make them you might like to add centers, although a dedture or centerless grind shop can make the without centers. If mine I would like them done between centers.

I would measure all the rollers to 25 millionths, and consider how you want to put them back...then selectively place them back. I am roughly thinking in a way that puts the largest at the ends tapering to small at the center.

You might find dowels or some other roller material source. One fellow I knew made such from CRS...likely originals were tempered.

Almost all the PM threads suggest locking the table any time you move a grinder, even if just around the shop...but done is done and I have also made mistakes moving machines.

I'll definitely consider making (or rather ordering) custom parts but I was hoping I could find something of the shelf. BTW, the rollers are hollow, If there weren't I guess it would be easier to replace them, as there is no problem buying precision dowels or pins.

I would sugjest to buy some needle roller linear cages
Like these
Or if you have more time as money make some from dowel pins Perhaps sorted to diameter (how good is the machine???)
and then have 3 cages made by waterjet out of brass or machine them yourself
Then some burs with a chissel to keep the pins captured in the slots but free to roll

Peter

I've seen this on multiple sites, but there was no purchase option on any of them... Only Chinese sites (i.e. https://www.alibaba.com/product-det...132.html?spm=a2700.details.0.0.9a9b4a74GPC3Rr).

What do you mean by "sorted to diameter"? To measure each one and sort them from smallest to biggest? How it would affect results I could get on this machine?

 

[michiganbuck]

Q Op: (What do you mean by "sorted to diameter")
Everything wears, with ball rollers I put them in an egg carton and place them back in the same order. With rollers (if they are worn) one would not like the center ones to be the biggest (IMHO).

Oil-wet rollers seem a good design so grits can wash off. I like to put a strip of masking tape (free to the lower) on the long travel table side to overlap the open parking space as an extra dust shield. . grits bounce off the column and get in the works on that side. Painted that tape is invisible and lasts a long time. If I designed a grinder I would have a felt wick there.

Oh..1.. With an over-tightened magnetic chuck a surface grinder top table is stressed to being bent upward at the ends and so the scraped oil ways, or the ball /rollers design wears more at the center area. Just imagine how two bolts 20" apart high-torqued would exert pressure.

2. Having full long travel over many years, or having two chucks or a long production job/part can wear the ways / or balls to be low at the ends...wearing the out ends ways or ball/roller lower.

 

[CarbideBob]

That is a Dunbar roller way kit.
https://dunbarrollers.com/index.htm
Not a Harig standard but I have used them for many decades.
Pluses and minuses and old school but I do like them for some uses. You should be able to remove them and use the normal ways.
On a rack drive there will be a spacer in the rack, in a cable often not.
DO NOT USE needle rollers in it's place unless you really know what you are doing about sizes and never use then or this on turckite ways.

 

[Wiktor]

That is a Dunbar roller way kit.
https://dunbarrollers.com/index.htm
Not a Harig standard but I have used them for many decades.
Pluses and minuses and old school but I do like them for some uses. You should be able to remove them and use the normal ways.
On a rack drive there will be a spacer in the rack, in a cable often not.
DO NOT USE needle rollers in it's place unless you really know what you are doing and do not use then on turckite.

Wow! That's interesting. So that would explain why the whole bearing were not mentioned in the manual.
Can you expand a little bit on the spacer? I have a cable version - does it mean I can just take off the rollers and use the SG as it is?
Why not needle rollers?
Turcite is kind of glue or other goo one can apply on the ways, is that correct? Why it is not applicable in my situation?

 

[michiganbuck]

Turcite Is a sheet or strip of plastic-type material that is glued in place, and then scraped in to be flat and true.
Richard King is the pro here at PM on scraping and the use of Turcite-type materials.

 

[eKretz]

Hi Wictor, nice to meet ya'. I haven't dropped a machine or machine part but I am pretty sure I know the feeling you felt when that happened. Looks like Bob nailed it on the Dunbar rollers. The goo/goop you're thinking of is probably Moglice. I wouldn't recommend that either.

 

[winger]

If I had to make them without a cylindrical grinder I would use Thompson shafting.
I was told to remove the table when I moved my grinder to prevent Brinelling from road vibrations. Not sure if that is real but it lowered the center of balance and made it easier to strap down.

Dave

 

[eKretz]

If I had to make them without a cylindrical grinder I would use Thompson shafting.
I was told to remove the table when I moved my grinder to prevent Brinelling from road vibrations. Not sure if that is real but it lowered the center of balance and made it easier to strap down.

Dave

Yes it's real. There have been cases of it happening related here at PM in the past IIRC. Iron on iron ways are fine to leave assembled for road travel. I would remove the table from a ball or roller way machine every time.

 

[Wiktor]

There is this polish proverb which translates to something that goes like "A Pole is wiser only after the damage is done" )

I guess I'll look into these two options - I'll try to use the grinder as it is, without rollers and in the meantime I'll find someone locally who could fabricate such rollers with enough precision.

 

[michiganbuck]

You might contact Dunbar to see if parts are to be had https://dunbarrollers.com/contact.htm

You might remove the roller racks, and hone over the ways with a hard India stone
then blue-in to see how that top and bottom match. Scraping may be needed, at least flaking for the ways to support having oil detents.

 

[Wiktor]

You might contact Dunbar to see if parts are to be had https://dunbarrollers.com/contact.htm

You might remove the roller racks, and hone over the ways with a hard India stone
then blue-in to see how that top and bottom match. Scraping may be needed, at least flaking for the ways to support having oil detents.

Do you think they still operates? Their website seems to be a little out of date... I paid something around 1200$ for the machine, so the rollers are a bit pricey for my liking..

I'll definitely start with geometry check. About the oil detents - they are present. What surprised me is how they look - first I thought it is corrosion pitting. They are quite deep with kind of sharp-ish edges.. I was expecting flakes - something like Moore pattern scraping marks.

 

[michiganbuck]

You might show a photo of the long travel bed way, who knows what may have been done?
the oil detents I am speaking are just flaking, somewhat like scraping scrapes, that are intended to process the oiling of the ways.

 

[LOTT]

Welcome to the forum and Harig fan club.

If you haven't already check out Robin Renzetti ("robrenz") on YouTube. He has videos on rebuilding a Mitsui (sp?), including making roller bearings. Might have some information/inspiration for you. Most of his work is done on a Harig 612.

 

[Peter from Holland]

Those linear ballbearings I did see a lott on toolgrinders Not on surface grinders here in Europe
Peter

 

[Scottl]

Wow! That's interesting. So that would explain why the whole bearing were not mentioned in the manual.
Can you expand a little bit on the spacer? I have a cable version - does it mean I can just take off the rollers and use the SG as it is?
Why not needle rollers?
Turcite is kind of glue or other goo one can apply on the ways, is that correct? Why it is not applicable in my situation?

Turcite is a low friction plastic material. It only works against flat surfaces and the pressure of rollers would deform it.

 

[michiganbuck]

Those linear ballbearings I did see a lott on toolgrinders Not on surface grinders here in Europe
Peter

I would wonder what happens to the parting opening between the top table and the cross saddle. Is it opened to 1/4" or so to let in all the grits bouncing off the column?

 

[CarbideBob]

The spacers are a must on gear drive and a somewhat on a cable system.
The height of things changes with this kit which should be obvious.

Needles and/or turkite.
The way hardness matters.
Easy to stuff in needles and make them work for a short while so any u-yuck without at least 10 years and a million cycles tells you nothing if you have a production machine.

If there are indents from transport removing the system will put you back on the original ways with no problems if you stone it lightly.
This would be my first go to but that left arm on you gets a workout now which is why the kit was there.
The whole ball of wax is more accurate and true running without this kit or any needle add on as this adds errors.

When converting production surface grinders to cnc I have done and played with this since the early 80's as stick and slip a problem in profiling.
Some good and some bad things along the way in short and long term use.

For flat conventional grinding that surface grinders were designed to do ... none of this is good for the parts or machine travel.
Ball or roller ways not so great and full of defection problems but easier to crank which is why they sell.

Note that there is a big difference in this and serious cnc machine tool ways and thier carts in design.
There I love the roller style for the huge dynamic stiffness numbers but a different animal.

This all messy and details.
If this kit and my ways indented I would stone with care and toss the kit to the trash can.
Bob