Thread: Lotze Power Hacksaw - Clean up

Hi,

Still going. Made a bit more progress. Have the motor and its assembly done, the bases and baseplate done. Now starting the rest. I will run out of time but that's not a problem, will be able to finish off next year.


Ben

Hi Guys I've joined the Lotze club. Mine has a few issues

It works kinda… the blade isn't tracking inline with the vice track i.i it is at an angle rather than parallel, and it seems to be wobbling about on the shaft. I assume buggered bronze bearings? Is there any other adjustment for alignment. The plate on the front of the saw which holds the blades on with a bolt also seem to protrude to far and interfere.


Also your all seem to have a handle with a red bakelite knob that sticks up at the rear? Mine doesn't

Could someone post a few pics of these things please.


One thing is does have is a belt guard which I think is cast, I may be wrong.

Originally Posted by bwal74

Hi,

I bought a Lotze power hacksaw late last year for $75 (or near abouts). It works but it was covered in years of grime etc so I took it to work to give it a bit of a clean up.

So I've totally stripped it, cleaned most of the parts in a parts washer and started to sand blast the castings. Mainly doing bits and pieces in my lunch hour so will take some time to finish.



Ben

Ben what grade/type abrasive did you use to sand blast the parts? Was it a good idea or did it affect anything???

Originally Posted by DSEL74

Hi Guys I've joined the Lotze club. Mine has a few issues

It works kinda… the blade isn't tracking inline with the vice track i.i it is at an angle rather than parallel, and it seems to be wobbling about on the shaft. I assume buggered bronze bearings? Is there any other adjustment for alignment. The plate on the front of the saw which holds the blades on with a bolt also seem to protrude to far and interfere.


Also your all seem to have a handle with a red bakelite knob that sticks up at the rear? Mine doesn't

Could someone post a few pics of these things please.


One thing is does have is a belt guard which I think is cast, I may be wrong.

Dale,

Ian's photo below shows the bow alignment adjuster and the end of the red balled clutch lever. The bow bushes can be replaced but you will probably find wear on the 1" diameter guide bar. I have mentioned this previously somewhere but be careful if you decide to replace the bar. I bought some PG 4140 for the job but Phillip "Metalman" scared me off when he said his casting cracked during the replacement procedure.

Both Ben's and my Lotze have cast aluminium guards, Ian's is naked.

BT

Hi Bob,

Which bit in the pic is the bow alignment adjuster? I have just scraped 5-10mm of black oily gunk off the entire machine. I'm sure someone dipped it in a tar pit.

I haven't had much of chance to see what goes where.




What does the ball-shaft lever do? Would it be possible for you to send me some dimensions to make one, next time your out in the shed.



The square bar in the photo seems to have bronze cushion blocks, is that correct?

Originally Posted by DSEL74

Hi Bob,

Which bit in the pic is the bow alignment adjuster? I have just scraped 5-10mm of black oily gunk off the entire machine. I'm sure someone dipped it in a tar pit.

I haven't had much of chance to see what goes where.




What does the ball-shaft lever do? Would it be possible for you to send me some dimensions to make one, next time your out in the shed.



The square bar in the photo seems to have bronze cushion blocks, is that correct?

I'll have a look when I'm next out in the shed Dale. The lever operates the clutch. The square bar and cushion blocks align the bow. They provide some rotational adjustability enabling you to set the saw to cut vertically. They are adjustable also to compensate for wear. These saws get covered in grit and that grit turns to grinding paste. If your bow bar bushes are rooted then the cushions have probably followed suit.

Bob.

PS. The knob is 35mm in diameter. The shaft is 7/16" in diameter and is threaded 3/8" BSW for the knob. I could not readily unscrew the shaft from the casting so the length of 160mm is from the casting . The last 15mm is threaded. I imagine the hidden end is threaded 3/8" also.

Hope this is of some use to you Dale.


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Originally Posted by DSEL74

Ben what grade/type abrasive did you use to sand blast the parts? Was it a good idea or did it affect anything???

Hi,

Off the top of my head I couldn't tell what grade the sand was. If I remember I'll have a look tomorrow when I'm at work. I haven't finished putting it back together and I probably won't do it this year. I was away for two months and starting holidays on Friday so it's been at the back of my mind at the moment. Since I'll have time next year (I hope) I'll hopefully measure the wearing parts, my bronze (?) cushions look stuffed etc.

Ben

Originally Posted by Anorak Bob

I'll have a look when I'm next out in the shed Dale. The lever operates the clutch. The square bar and cushion blocks align the bow. They provide some rotational adjustability enabling you to set the saw to cut vertically. They are adjustable also to compensate for wear. These saws get covered in grit and that grit turns to grinding paste. If your bow bar bushes are rooted then the cushions have probably followed suit.

Bob.

PS. The knob is 35mm in diameter. The shaft is 7/16" in diameter and is threaded 3/8" BSW for the knob. I could not readily unscrew the shaft from the casting so the length of 160mm is from the casting . The last 15mm is threaded. I imagine the hidden end is threaded 3/8" also.

Hope this is of some use to you Dale.


288 (Large).JPG 289 (Large).JPG

Thanks Bob.

That should be enough info to make something to do the job. Since the Lotze is a stick shift with a clutch that should keep the missus from driving it


My saw is out of alignment along the length of the blade. Will the cushion block correct along this axis or just the camber of the cut (Z axis)?
There seems to be a steel bush with a flange end on the cam arm where it attaches to the cam wheel. THe arm is hard up against the wheel and the bush is protruding from the arm by 10mm or so. I'm assuming the flange should be seated flush in the arm.
Like this one.
lotze7.jpg


Tomorrow is learn to rewire to Delta day, so I'll have a fiddle with the lotze more on Friday hopefully.

Mine doesn't look like that Dale.

I will try to pull it apart and photograph it on the weekend for you.

Bob.

Blade alignment:

There's been some good comments from Bob, and much of this is repeating that advice in other words, but here's my take on it from my experience:

If the problem is that the saw cuts at an angle as it cuts down through the material, so that your piece ends up with a skew cut (angled top to bottom), then you have a fairly easy fix.

Look at the square-section guide bar. There are two cast bronze pads, one on top of the guide bar and one underneath, which travel along the guide bar as the saw reciprocates.

You can play with the tightness of the bolts that hold these pads to the guide bar. By slightly slackening the top bolt and tightening the underneath one, you will get the blade to square up or cut even more skew (sorry I forget which); and of course slackening the bottom bolt and tightening the top bolt will have the opposite effect.

If the saw is out of square with the vice, (out of square with the length of the blade) then reset the fixed jaw of the vice. After all the vice jaw is only clamped down with a bolt and a clamping piece, also bolted down.

It's probable that the bronze bushes on the saw guide arm (the guide with the round section at the back of the saw bow) will have worn. Mine are, and this creates a little bit of rattle. But the adjusment I described above is, in my case, enough to overcome any problem of cutting skew. I suppose the day would come when the saw guide arm bushes will be so worn that they really do have to be replaced. The only way to attempt that would be with a hydraulic press - because the alternative of hammering the bushes could, as has been mentioned, crack the saw arm. Actually, my concern on my saw is that one of the bronze pads on the square-section guide bar is wearing quite thin - even thinner than I remember it being when I first got the saw - and getting (or more likely, making) replacements would be an involved task. But not yet, so that's a probelm for the future.

Ian

Well it was one of those days when I really didn't want to get out of bed, and I damn well shouldn't have.

And I was just trying to get the socket on by hand over the extra paint. So it was possibly already broken undercover paint. This wasn't the event the axis I needed adjustment on.


I think it was mentioned someone else had this break on them...how did they repair it?




I feel like there is a spacer missing here?




Maybe I should push it under a bench and forget about it.

On the plus side, you have grease / oil nipples on yours... I don't have such luxuries. Also, your rear bronze bush holding the 1" dia bar looks to be in better condition than mine.

Is your 1" shaft straight along its length or does it have some wear? Mine has a little, but I suspect 2 new bronze bushes will fix that, or at least make it a lot better!

Originally Posted by ventureoverland

On the plus side, you have grease / oil nipples on yours... I don't have such luxuries. Also, your rear bronze bush holding the 1" dia bar looks to be in better condition than mine.

Is your 1" shaft straight along its length or does it have some wear? Mine has a little, but I suspect 2 new bronze bushes will fix that, or at least make it a lot better!

If your referring to the shaft and bearings attached to the bow then they seem good.

My movement is coming from the drive shaft. maybe the bearings or the whole assembly isn't attached to the main base casting.

Dsel, it's starting to look like maybe you should do a tear down and rebuild, given that now you aren't sure of the drivetrain, in addition to various other issues.

I didn't fully understand one of you photos, is it that one of the lugs for the square-section guide shaft bearing pads is broken off?

Ian