Grizzly G8750 compound slide table

[iplay1515]

I recently purchased Grizzly G8750 compound slide table to use as a general purpose x-y table and to experiment a little more with CNC.

One set of the dove tail ways on each axis is polished but the opposing set appears to be just ground down with a rough cut rotary grinder or other type of cutter. They are certainly far from being polished. Each axis also has an adjustable gib strip with one polished side that rubs against an unpolished dove tail.

Is this normal for a dove tail type of table or is the machining on this table incomplete?

For the price, the table appears to be a good value with the exception of the damage it sustained to the lead screws during shipping due to very poor packaging. Grizzly customer service has promised a new set of screws, but haven't given me a firm ship date. So far it's been a week since they were notified of the shipping damage.

[Pete]

Yes and no - Grizzly provides good deals for the price but you have to ususally take the things a part and clean them as well as polish running surfaces.  You can usually significantly improve the smoothness of operation by polishing the gibs - but dont reduce the thinknes much or the gib wont function properly- it will flex to much. Polish the gib smooth and flat.

Typically in the more expensive equipment you dont have to do this but you generally pay 4-5 time more for the same items.

[iplay1515]

Thanks. Any idea why one surface of a slide would be polished so well and the mating surface left rough as a cob?

[ozzie46]

   Just guess, maybe to retain lubricant? A well polished surface has no place to retain oil. I've read that the scrape marks on older machine tools served this purpose as well as leveling out the ways.

  Ron

[iplay1515]

The material is cast iron, and the rough surface consist of machine marks like you would see from a dovetail cutter.

[iplay1515]

There is a pretty big difference between the schlepping performed to retain oil and the cuts left by cutting.  Some newer machines get this treatment on the tables as well as the ways...

I recognize the machining shown in your photos, and what I am calling the polished surface more closely resembles your photos.  However, the mating surface looks more like the marks left by a fly cutter on aluminum plate.  I'll take some photos of each surface tomorrow and post it here.

Thanks.

[ieezitin]

The surface finish you got from the tool supplied from grizzly is a reflection on the price you paid for it. Saying that is it functional?. Have you tried putting indicators on the X-Y and got readings? If so are they acceptable.

People buy products from china all the time and tweek them into something that suits their needs.
The ground surface finish should work fine and I would not worry about it like I mentioned earlier does it work for what you want it to if it does not! what’s the problem then concentrate on that.

All the best        Anthony.

[iplay1515]

The surface finish you got from the tool supplied from grizzly is a reflection on the price you paid for it. Saying that is it functional?. Have you tried putting indicators on the X-Y and got readings? If so are they acceptable.

People buy products from china all the time and tweek them into something that suits their needs.
The ground surface finish should work fine and I would not worry about it like I mentioned earlier does it work for what you want it to if it does not! what’s the problem then concentrate on that.

All the best        Anthony.

I agree.  At the moment, the table is down due to lead screws that were bent during shipment, so I have been unable to make any serious measurements.  My question is really about why one surface is ground or polished smooth and it's mating surface was left with cutter marks.  It makes me wonder if some steps were skipped during manufacture.

See attached photos.

[ieezitin]

Well I see the close up. As for a definitive answer I cannot say why but I will say it will retain oil better which is a good thing. It’s a lot harder to surface grind the female of a dove tail than a male, I would bet that’s a good reason.

Anthony