Lenz LPA 1s Boring Head

I am in a quandary as to what to do with a Lenz LPA 1s automatic boring head I have acquired.

It looks to be in good condition and the first ring on the head (lower ring) certainly moves the slide left and right but then I realised the second ring (Upper) did nothing even when the engage plunger was pushed in.

On investigation the upper section seems to be missing a number of vital components…

Plunger would have activated a second inner wheel (toothed cog) however there appears to be a ball / tooth missing to engage the wheel. This is an easy fix…

But then I realised that with the inner wheel engaged…. There is a ???? missing to connect the inner ring to the second ring. The second ring appears to have a mechanism similar to a brake, or engagement lever. The wall also appears to have a ridge applied to it so that something can temporarily lock in place….

Does anyone have an exploded diagram of this type of head as I have trawled the intraweb thingy and there is nothing?

Any help restoring this would be appreciated.

Dan

I think there might be two small gears missing from the two posts stuck up from the underbelly

I'm not familiar with that particular head, but have recently stripped a poorly Kuroda head which looked very similar in design, and it had the two small gears.

have a look in my photo archive, there are some pictures which might explain better.

Hi Alan,

I really appreciate the quick reply. I tried responding sooner but go tied up in bureaucratic paperwork.

I had wondered what those pegs were however having looked at your photos which has a gear upper and lower and from the photo above the toothed wheel is split which I had originally thought was done to slot the upper ring so that it could be engaged via the plunger.

I am now thinking that the geared wheels that sit on the pegs could also be split. one for upper toothed ring and one for lower ring....

What gives me a bit of confidence is that yours is not a Lenz and there are similarities so I might start trawling the tinter thingy for a manual on any old auto head.

Dan

Dan

By some mad coincidence I've just picked up a complete and (hopefully) working Lenz LPA1 as a replacement for the defunct Kuroda, it came with a full instruction and parts manual complete with drawings. Have got a pretty full on week coming up, but if I get the chance I'll scan it for you, if not, then will do it at the weekend. Bad news is you should definitely have two small planetary gears present.

Al.

Edited By Alan Waddington 2 on 10/10/2016 22:51:54

Thanks Al, that is fabulous, best news I’ve had all week. It was becoming a bit of a jigsaw puzzle without the box.

Dan

Here you go Dan, hope it helps

https://www.dropbox.com/s/ca744p3lbrnrpey/img018.pdf?dl=0

Alan, You are a life saver. That is even more detailed than I had expected. Can I offer you something for the trouble you have gone to?

Dan

Glad to help Dan, that's what these forums are all about........goodness knows how we all managed before the internet

I can see that the shank on the head is threaded . I have a possibility of obtaining a Lenz LPA 1S but it is on an Int 40 arbor. I want to be certain how it comes off before purchasing it. Can either of you two gentlemen tell me how it is removed.

Thanks,

Colin

I have the same boring head on a R8 shank. It has 15mm holes for the cutters but nobody seems to supply these. I would appreciate any ideas on the best route forwards. Can larger boring cutters be ground down? Can the holes be easily opened out to 16mm. Does anyone service these heads? I would like to get it to work because otherwise I rely on a c****y Chinese boring head which is rubbish to set very accurately.

regards

Chris

You could just turn a reducing sleeve to fit in the 15mm hole and bore it to take 12mm or 1/2" tooling, put ahole in the side so the grub screw bears on the tool and does not crush the sleeve.

Or just make a simple 15mm dia bar drilled through for an hss toolbit and cross drilled for a grub screw to retain the bit, something like this

Both these options are standard equipment for boring and facing heads and also better quality boring heads, even those from the far east

Edited By JasonB on 11/02/2019 08:17:59

Very helpful posts here. Thanks for the link to the instructions for the LPA-1S. I still have a few matters on which some advice would be most helpful. Mine has a Bridgeport shank and there is no top screwed washer - at least not one that can be seen or be accessed. I have only managed to get the bottom sliding toolholder off with some difficulty because the grease is perhaps 50 years old. That leaves a body with no way to get inside to clean it out. I contemplated a degreaser but that would not allow me to regrease it. So, first issue, how do I get inside the body? Second problem is - what is the best grease? Third matter is - the marks on the setting ring are almost unreadable when the head is in use. Does anyone know of some magic paint or enamel that can be applied and will stay lodged in the serrations so that I can (at 82) read them? regards to all Chris

Chris,

Have you actually managed to get the shank off. I have a LPA 1S. Between a colleague and myself (he did the accurate work) we have fitted it with a MT3 arbor instead of the Int 30 it came with. What screwed washer are you referring to. When the shank is off mine there is what appears to be a spacer washer between the head and shank but this is not screwed. Mine has some reducing sleeves as mentioned by Jason. The recommend way to remove the shank appears to be to use the extender arm or a long bar in the lengthwise hole in the head and with the assembly mounted in the mill arbor use the arm or bar to unscrew the assembly. It is a fine right hand thread in the head.

Colin

Colin. Thanks for the post. I took a long look at my LPA and decided that the Bridgeport R8 shank HAD to be taking the place of the screwed washer referred to in the instructions that Alan provided. I put the head between the jaws of a vice with rubber jaw liners and, having tightened the heck out of it, I put a 21 mm spanner on to a couple of flats that I noticed on the R8 shank and, lo and behold, the shank screwed off in one piece. I found everything in good order under the two knurled rings except for the very old grease which I softened by mixing with a little oil. I still have to get into the rest of it but am inclined to leave it for use only as a boring head and leave the facing mechanism alone - at least for a while. On the matter of the 15 mm holes for tooling, I decided to try to turn down the shank of one of a set of 18 mm boring tools. I found the material to be not very hard. I had imagined it to be very hard due to its shiny grand surface so I now have a set of 15mm boring tools with a step up to 18mm. The step sits on the edge of the 15mm hole and helps to add rigidity. I would still like to try to get a contact for sales and service of these heads if they are still made.

Just a quick addendum to this post. The arbor I removed appears to be an Int-40 not a 30.

Colin