Kuroda UPB-3S Boring and Facing Head

I am looking at buying a Kuroda UPB-3S boring and facing head for use on my Bridgeport. As far as I can see the head is an improved copy of the Wohlhaupter UPA-3, but specifically intended for the Bridgeport; to the extent that "Bridgeport" is engraved on the body.

I have a Wohlhaupter UPA-4 head that I use on the horizontal mill and love it. But does anyone have practical experience of the UPB-3S head and how it performs in the real world? Or even better access to a manual! Unlike the UPA-3 the UPB-3S has two feeds for facing, 4 thou and 8 thou per rev. Does anyone know if these are independent or, like the UPA-4, can be used in conjunction to give 12 thou per rev feed?

The internals look pretty complex, basically epicyclic gearboxes for the feeds, so I am being slightly wary as the seller claims the head and accessories are in excellent condition. But after asking for extra pictures he "discovered" that one of the boring bar holders was broken. That should have been pretty obvious. Again, after asking, he also confirmed that one of the reducing sleeves is missing; no big deal but should have been mentioned. I am wonder what else is hidden?

Andrew

Just my 50 cents worth but I think I would walk away from it. If one of the boring bar holders is broken you can bet it has had a crash into something. I have used wohlhaupter heads all my working life and am now the proud owner of a UPA2, they don’t take kindly to accidents and I imagine this UPB 3S will be the same. Can you get spares for this head, does anyone repair them or agents in this country? If it’s going for silly money cheap you might just get lucky. Is he close enough to you so you could see it working?

My twopennorth is the same as Baz for the same reasons, I have used Wohlhaupter & Kaiser all my life, never heard of Kuroda but they do have an agent in the U.K. but no mention of boring heads on their web site product list !

Plenty of used Wohlhaupter available but if the Kuroda is VERY attractive price wise I would contact the makers/agents and check out the spares situation before going further.

John

Edited By JohnF on 03/12/2022 13:59:43 spelling 

Edited By JohnF on 03/12/2022 14:00:27

There are a couple of older threads on Kuroda boring and facing heads. Consensus seems to be that they are essentially the same as Wohlhaupter in all important matters.

Kuroda haven't made such tooling for a long time, perhaps 20-30 years. I have seen it said that they transferred all rights and historical records to another company around a decade ago when they finished shifting their business to other fields.

Given the well known intolerance of such devices to careless handling you need to be very sure that its in good order before buying. Mostly works isn't good enough when finishing off at the bottom of a hole.

Generally "excellent condition" is best translated as "scrubs up half decent" and refers only to cosmetics. Agree with Baz that anything broken means its been seriously crashed which almost invariably results in internal damage. Even if it still appears to function.

I always wanted a boring and facing head but long ago decided that the only safe buys were cupboard queens that had seen little use. Way out of my price range for the little use it would see.

Andrew, the very fact that you are posting this means your spidey senses are twitching. Trust them and walk away.

Clive

That is very perceptive, and correct. The little voice is no longer little, but is now hammering on the door and shouting don't buy it!

Following on from the comment by Baz and John a close look at the pictures shows some slight scarring that indicates a possible crash, despite the overall head looking to be in very good condition with nice clean edges and none of the little dings and dents one normally sees. I am assuming spares are not available at any price.

On the plus side it looks to be a lovely head and I am fed up to the back teeth with my R8 import boring head. On the minus side the seller has responded quickly, but has avoided my direct "does it all work correctly" questions with woffle about the slides moving freely. The head has been on the same site, at a higher price, before but was withdrawn by the seller, which is a red flag. Asking price is £600 which I would pay for a fully working head. But not this one; listing ends on Wednesday so I am going to walk away and see what happens. If it dropped below £100 I might take a punt, but not otherwise.

The seller is in Rugby, so not out of the question to visit, but an hour and a half or so each way. Slightly strange selling history too, lots of bench vices, but then the odd large Harrison or Colchester lathe.

Andrew

Other than the small difference in country of origin, would this one suit?

https://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Boring-Tools/Universal-Boring-and-Facing-Heads

The page even answers your question about feeds.

DC31k

Now that is just too tempting. Unfortunately for Ketan my flexible friend has just taken a £1,000 hit and will be in recovery mode for a while!

Given Arcs well established reputation for providing more than acceptable quality at, potentially, affordable prices and that £600 (ish) seems to be the established used market price for a complete boring and facing head kit buying new would seem to be a no-brainer.

Assuming the capacity is sufficient for the jobs envisaged.

Clive

I am lukewarm on the old-style brazed carbide bars supplied with it.

This might be one to which we could aspire:

https://www.west-point.co.uk/product/2440/narex-model-vhu-36-boring-and-facing-head

I would love to find the indexable bars shown with it in 3/4" shank. Gloster Tooling have a set and they are the only UK ones I can locate. There are 20mm shank ones from China ('NBH 2084' will find them). I wonder how easy it would be to grind them down to 3/4"?

DC31k

That Narex set is really nice but its nearly £2,000 which none of us can justify. Pity.

Mega extra money to get better boring bars.

Could the insert type boring bars made for turret heads be adapted to fit the Arc head. Cutwell offer the QGCT range from Teknik at just under £70 which isn't impossibly expensive and seem to tick all the boxes. Presumably a set of extensions could be made to allow one toolholder to cover all depths. Obviously rigidity will suffer but these are intended for turret use on lathes. Boring and facing head duties are rather lighter.

Clive

Update: In response to my last question the seller has stated he has no way of testing the boring head. But he has offered to refund my money plus pay the return postage if I am not happy. Not sure what to do now. Could possibly collect so at least I know where he is. Also I don't really trust the auction site on which the item is for sale in the event of a dispute.

I bought a 25mm insert boring bar for my Wohlhaupter head when boring my cylinders. The shank was simple to turn down using normal insert tooling.

Andrew

Looks like the UPB-3S / UPA-3 heads are the same size and capacity as the one from Arc.

if the price for the used head is still of the order of £600 buying from Arc would seem to be a more sensible option.

New-New and you know its going to work as it should.

Maybe not the same ultimate quality as a proper industrial rated head but I'd be willing to bet it will perform as well as a used industrial one for more hours than you'll put on it. Once tooling gets above the economy ranges to decent but still affordable the main difference relative to general industrial use quality is in how long it will continue to work for before wear causes the quality to drop off.

Even if you decide to pay extra to buy insert type boring bars there is still much potential bother and time wasting if the used one is fundamentally sound but not quite right. it may be hobby use but we still don't have time to burn on peripheral activities.

Clive

Just had a look at the boring and facing head on Arc euro site and it looks quite impressive, I think that If I had £600.00 to spend I would rather buy Arcs offering rather than a Kuroda of unknown provenance. Usual disclaimer applies, just a well satisfied customer.

Quandary solved; the seller accepted an offer from someone else. For their sake I hope it works.

Andrew

Kuroda boring facing heads are a really nice piece of kit. Like any thing though, they need looking after.. Our one only had 2 facing feed rates and they could not be used together to get a higher rate. Mostly used the lowest feedrate on facing anyway. I did like the feed stop, but you needed a light cut to be able to feel the stop when it got there.

Addendum

Over the past few months I have continued to look for a boring and facing head for my Bridgeport mill, without much success.

Recently I looked at a Wohlhaupter UPA2 head, but it didn't have any accessories and had an integral Morse taper shank. The seller also used the "I don't know anything about this" routine when asked if it was in full working order. I then looked at a Wohlhauper UPA3 head in excellent condition with a full set of accessories and a helpful seller. But sadly it had an integral MT3 shank and I couldn't think of a satisfactory way to replace the shank without a lot of work, and devaluing an expensive item.

Then I lucked upon a Kuroda UFB-3-F head with an R8 shank and a full range of accessories. A big plus was that the seller was 15 miles away. After an exchange of messages I went to look at it yesterday. The head is in good condition, plus the seller was a professional machinist and clearly knew his way round the unit. He had bought it from his workplace so also knew it's history. The upshot was that I agreed to buy it and he let me take it away on a promise of paying today. Here is the box of goodies:

The only downside is that one of the sleeves has been split, although it is still usable. The extension arms look to be unused and it even comes with the tapered lever for pulling and pushing the various pins in and out. Everything seems to work as it should and there is no evidence of any crashes. Of course the acid test is to run it on the Bridgeport, which I will do later this week.

I'm not going to say how much I paid as it will probably upset some people. Let's just say I fall into SoD's category of those who like to own, and use, nice tooling and am fortunate enough to be able to afford it. No significant other to stop me for a start!

Andrew

Andrew that looks to be a nice bit of kit, nice to have the provenance as well, good quality tooling like this is getting harder to find and when you do find it you have to pay well for it. I also like to own and use nice tooling but mine usually costs me double because the wife wants sewing machines or patchwork material to the same value!

Nice, it's funny how you can scour the country for months and then the ideal thing turns up on the doorstep.

Even the box looks straight which is a good sign for something from a works.

I am about to order a Vertex boring head which uses boring bars with inserts, not the braced types of which I have a 12mm set, would this be a good deal, your opinions-?
Vertex:
-VBC-2M VERTEX Boring Head 2C - 50 Dia10-100 Cap
-VBC-MT4 VERTEX Boring Head Arbor - 4MT
-S12M-SDUCR07 VERTEX Bor Bar s rh -12mm DCMT070204
-DCMT070204 Inserts DCMT070204

I never really got on with my budget Soba boring head for the Bridgeport, hence the Kuroda purchase. The socket head grub screws (Whitworth thread) were poor quality and have been replaced where possible. I found it difficult hold a tolerance as the adjustment screw was quite sloppy.

I have used insert boring bars with my Wohlhaupter boring bar in the horizontal mill. But I had a lot of trouble with chatter and a poor finish. To be fair I was pushing my luck on the length versus diameter of the boring bar. But I don't think boring heads really run fast enough to gain benefits from insert tooling. In the end I reverted to boring bars with HSS tool bits with the Wohlhauper:

With a HSS toolbit it is easy to control the shape of the cutting edge and the reliefs.

With the Soba head I found it to be a crap shoot as to whether one could hold a diameter to a few thou. Whereas with the Wohlhauper, and I hope the Kuroda, holding to less than a thou is straightforward.

Andrew

I've been playing with the Kuroda boring head on the Bridgeport this evening, boring and facing:

All functions seem to work and the head is a joy to use. Put on a 0.025mm cut and as near as I can measure the hole diameter increases by 1 thou (I don't have any metric internal micrometers). it was simple to get the hole diameter to size within a couple of tenths, on the micrometer reading at least.

I like using nice tools.

Andrew