Thread: Tool Post Grinding

Bob I'm not sure if Enco sells the "real deal" but when you mentioned that size was difficult to obtain out here I thought I recalled Enco having them, and indeed they're listed at the bottom of the page I linked to. Almost certainly they're out of Asia, however they may give you a few more options regarding grit etc. At 10 bucks a go they're not that expensive and the good thing about wheels this size is they're not super heavy, so freight doesn't so readily become a deal breaker.

Good luck with it, for what it's worth the finish looks superb in the photos!

Pete

Hello Pete,

Enco's website is down at the moment, preventing a search for bargains.

The photos lie.

To the naked eye, the finish looks good. Seen through a 2 1/2X jeweller's loupe. the finish is lousy. A lot of irregular depth and spaced grinding marks.

As an unfair comparison, viewing a ground surface on my Schaublin dividing head with the same loupe, reveals perfection. Not that I would ever expect the liitle grinder to acheive similar results becase it just couldn't but with some more fiddling I should be able to improve on what I have done so far. Fingers crossed.

Had it not been for the observations and comments of interested forum members, I would have placed the thing back in it's box, having abandoned, yet again, the idea of being able to use the thing properly.

Bob.

Came across this article you might find interesting, if you have to replace the power cord.

Projects In Metal » Blog Archive » Rewiring (Replacing the Power Cord) on a Dumore Tool Post Grinder for the Lathe.

Ken

Originally Posted by gregoryq

Bob, I am wondering if there's something in the lathe's leadscrew which is giving you a periodic error. If the defects aren't exactly spaced, then forget that idea.

Further to Greg's suggestion, I'd suggest it doesn't need to be in the leadscrew either, if there is ANY damage to either the gear on the back of the spindle or the tumbler gears on a Hercus, that will be transmitted through to the finish by moving the spindle slightly at regular intervals. When I first got mine it would actually turn considerably out of round for this reason when power feeding due to some damaged tooth profiles. I understood you used two separate lathes on your tests, which would imply that's not the problem, but if using the leadscrew maybe try feeding manually and see if the pattern is identical.

Pete

Bob, have you tried Siegling belting in Weshpool. I had some belts made there for a Waldown TP grinder, just ask them to scarf join the belt, seems better than the usual lap joint. Alan.

Hello Ken,

Thanks for that. I did have to replace the cable on the grinder. I did not remove the stator. The machine had no switch when I purchased it on Ebay from Dave "Tissuescars" about four years ago.

If I recall correctly, the machine came from BHP Engineering in Sydney and it had been modified for a particular job. Dave had two No.44 grinders up for auction at the time. He correctly stated that this one was in need of repair.

I installed a cheap toggle switch bought from Jaycar. The conical shroud was formerly a cast aluminium pulley. The original Dumore switch and shroud were cheap enough, less than twenty bucks, but getting hold of them was another issue.

I connected to the internal wiring by soldering and covering the joints with three layers of heat shrink tubing. It all works well.

Bob.

Hello Pete,

I should say that any attempts at grinding on the ARL were half hearted. I had not adopted the use of the plastic dropsheet to cover the entire lathe. I was using sheets of newspaper and old rags. The dust gets everywhere.

The results I achieved were poor enough to quickly abandon the thought of continued trials on my prize lathe. I thought, probably erroneously, that the roller bearings may have contributed to that finish.

The older plain bearing A runs very smoothly, with no discernable vibration. The cast iron legs appear to provide more rigidity than the sheet metal pedestals of ARL.

I will continue my experiments after replacing the motor bearings. I have a crank handle that I fit into the rear of the spindle for hand threading. Using it to rotate the spindle at Dumore's recommended 50 rpm might reveal whether the back gear train is influencing the finish.

Bob.

Hello Alan,

I had a belt made by Habasit in Malaga. You can feel a slight increase in thickness at the joint as you can on the two Dumore belts. I'm sure that the belts cause some vibration but the greatest reduction in vibration has come as a result of swapping the armature.

Tell all of us more about your Waldown TPG.

Bob.

I would like to see it as well if you have time.
I am watching with interest as I want to make one myself because they are to expensive to buy.Their are lots of guys that have made their own and are getting good results with them.
I did use a dremal to true up a coaxial indicator shaft as it was all I had and it turned out ok, but a proper tool post grinder would be superior.

When I was down at H&F's before christmas they had 2 tool post grinders on the damaged/shop soiled section at $500 each instead of the $1200 odd they are new. They where a bit to big for my lathe but I notice they don't have them on their website anymore so maybe their where problems with them.

Dave

OK, attached I hope are some staged photos of the Waldown - 0 on a Colchester lathe. Don't use it much now due to having a cylindrical grinder, however when I did use it surface finish was never the best, I'm sure due to rigidity of the entire setup and also not using coolant. OK for the odd touch up job a the time though. The motor at 12,000 rpm sure makes a noise. Also the internal spindle in 1 of the photos, never got to use it though. Bob I'm sure the scarf joint belt would help a bit as this is what I had to do on a surface grinder as the join was pantographing through to the surface. Alan.

Alan,

There is no snap shot.

Bob.

Bob, pm sent. Alan. OK they have now shown up, a bit big but better than nothing I suppose. Ah! DJ I now see it, thanks for doing whatever magic was required. Alan.

Alan,

Great photos. I was told by one of the blokes at Hughans Saw Service in Osborne Park that Brobo Waldown had ceased the manufacture of their TPG's a few years back. It's a shame because they appear to be a nicely designed and made tool. In reality, I guess TPGs fit into the Jack of All Trades, Master of None category.

Whilst we see few Waldown TPGs for sale here, there is always an abundance of Dumores on offer on US Ebay.

I'd love to get hold of a small tool and cutter grinder ( along with everyone else! ) But how often do they surface!

Bob.

Pete F asked whether I had resolved my problem with surface finish using the Dumore. To eliminate the motor as being a possible cause of chatter, I swapped the rotor. I removed the bearings this afternoon. The drive end bearing is a Fafnir 202 KDD, a standard size, single row radial ball bearing 15 id x 35 od x 11 thick but with C4 clearance. Things do get hot as a result of belt friction but I am not sure it would require a special bearing.

The other bearing is a Nachi WBC 202 W1WZNSL. Again 15 x 35 but 12.7 thick.

The Fafnir is knackered. The Nachi, not perfect. I will try to buy new bearings tomorrow.

If there is a problem with the availability of the Nachi, what are my chances of removing the synthetic rubber seal, flushing, regreasing and refitting the seal?

BT