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Balzer relieving attachment working model

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Pete Rimmer11/12/2019 02:12:02
729 forum posts
49 photos

Being new to 3d printing (4 days in) and needing something interesting to really get stuck in to learning how to draw and print models I decided to see if I could produce a working model of the Balzer device. Here are the results. It's definitely a bit rough and ready, and a couple of things need a tweak here and there but it's a fully working model operated by the hand crank.

Hope you like it. I'll see if I can take a short video of it working. All-white is a bit of a devil to photograph I have found.

The gears took a bit of designing. One of them has two different DP teeth on the same gear and the small orbiting one has a different pressure angle to the other two, in order to make everything mesh.

Hopper11/12/2019 07:30:58
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4634 forum posts
101 photos

Very clever, and nice work in the execution. Look forward to the video of it in action. I've looked at the patent drawings and description of its operation online but just can't get my head around exactly how it works without seeing it in action.

Michael Gilligan11/12/2019 08:07:29
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15852 forum posts
693 photos

Nice exercise, Pete yes

+1 for the video request.

MichaelG.

Brian Wood11/12/2019 08:37:54
2202 forum posts
37 photos

Count me in too please, I couldn't figure out how Balzer got over the mismatch in tooth count. Very clever and nicely re-engineered

Brian

Michael Gilligan11/12/2019 09:27:07
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15852 forum posts
693 photos
Posted by Brian Wood on 11/12/2019 08:37:54:

Count me in too please, I couldn't figure out how Balzer got over the mismatch in tooth count. Very clever and nicely re-engineered

Brian

.

Have a look at Ferguson’s Paradox, Brian.

One of the useful implementations of the idea was the dual-reading Imperial/Metric dials on some milling tables; which had 125 and 127 tooth internal gears.

MichaelG.

Kiwi Bloke11/12/2019 10:06:01
443 forum posts
1 photos

Neat! I too will be waiting for the video!

'One of the useful implementations of the idea was the dual-reading Imperial/Metric dials on some milling tables; which had 125 and 127 tooth internal gears.' And, of course, Graham Meek's ingenious saddle handwheel dials (qv).

Edited By Kiwi Bloke on 11/12/2019 10:07:56

Brian Wood11/12/2019 10:35:06
2202 forum posts
37 photos

Thank you Michael, it never fails to impress me how far your knowledge base goes, I will follow that up.

Regards Brian

Pete Rimmer11/12/2019 11:03:32
729 forum posts
49 photos
Posted by Hopper on 11/12/2019 07:30:58:

Very clever, and nice work in the execution. Look forward to the video of it in action. I've looked at the patent drawings and description of its operation online but just can't get my head around exactly how it works without seeing it in action.

The secret is in this gear, in the pic it's the one with the peg that stops it turning. The top half has 4 more teeth than the bottom half. Because the flying pinion HAS to mesh with both gears, the left gear is advanced 4 teeth during the bottom half of the rotation.

I originally printed the gears as 14.5PA but found that the teeth were too fine for the printer. Just like 3-d printed holes come out under-sized the teeth were slightly crowding into the gaps. I got over this by increasing the PA to 25 degrees which made the teeth more triangle-shaped, and printing the gears on a raft to raise them off the heated bed somewhat. Later I increased the PA of the bottom half teeth of the split gear even further to 30 degrees, to aid the meshing of the pinion over the mis-matched tooth size.

The actual cutting action is caused by the two end-pivots being off-set by 1mm so as the workpiece 'speeds up' it also moves towards the cutter,

 

Edited By Pete Rimmer on 11/12/2019 11:06:56

Michael Gilligan11/12/2019 13:55:44
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15852 forum posts
693 photos

Here’s an earlier thread : **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=143993

MichaelG.

Pete Rimmer11/12/2019 14:10:25
729 forum posts
49 photos

Here's a link to the video of me working the model. Sorry about the white balance, it looked fine on my phone, only came out too white when I converted it for sharing.

Balzer Reliever

 

ARG, looks like dropbox has ruined the quality. I'll have to fix it later.

Edited By Pete Rimmer on 11/12/2019 14:11:22

Brian Wood11/12/2019 17:06:04
2202 forum posts
37 photos

Hello Pete,

I was able to view that just fine, it really is most ingenious and thank you for taking such considerable trouble in recreating it.

I imagine the 'tuning' of it to get the relieving action in the right part of the cycle is another carefully planned part in the manufacture of the eccentric shaft it all revolves on, just as it is in Eureka.

In full sized use for relieving actual cutters, I would expect gear wear to be pretty heavy. Do we know if it was ever used in anger?The alternative that Eureka was based on was used successfully but dropped out of favour when suitable relieving lathes became available where powered slides could be used to carve off metal.

Regards Brian

Pete Rimmer11/12/2019 18:45:39
729 forum posts
49 photos

You're right about it would need careful timing Brian. I just used the orientation of the gear in the patent and though the motion is not perfect it's good enough to be indicative of the operation.

I never found any evidence of a real working one. It does have some limitations, such as it will only produce 15-tooth cutters unless you find another combination of gears that will work out to different number of tooth advancement whilst being close enough to a similar diameter that the meshing can be fudged by profile-shifting. I haven't looked at it closely but what little I have done suggest that there can't be too many options. The Eureka machine on the othr hand is very easy to change the tooth count, plus it doesn't suffer the problem of meshing mis-matched gears.

Pete Rimmer12/12/2019 15:44:41
729 forum posts
49 photos

I've saved all the components now and just doing some test prints. Is anyone interested in either the Sketchup file or the .dae for their slicer? If so I can publish them, if I knew where the best place was to do it.

Jeff Dayman13/12/2019 16:59:41
1827 forum posts
45 photos

Hi Pete, great job on the 3D print of the Balzer device. I'd like to print one. You could share the STL and/or the STEP files of the device on Thingiverse, for all to see. You do have to join Thingiverse to do that but it is free, and membership there has been no hassle for me, so far, anyway. You can control whether others can alter and re-post the device there.

If that's not an option, you could just ask people to PM you with their email addresses and you could send stl and or step to them on an individual basis. In case you want to do that I'll PM you now. Thanks Jeff

Pete Rimmer13/12/2019 21:36:03
729 forum posts
49 photos

Thanks Jeff for the compliment.

I've published the files on Thingiverse for anyone to download.

Balzer Reliever - Thingiverse

Jeff Dayman14/12/2019 15:32:53
1827 forum posts
45 photos

I used Pete's gcode file from Thingiverse to print a Balzer mechanism. Excellent quality print. Thanks again for sharing it Pete. As far as I know this is the first one printed in Waterloo Ontario Canada so I added a Canadian flag. Looking forward to assembling it in the shop later today.

There is a tiny bit of stringing around the raft base, but that is usual for my printer. The parts above the raft are very clean with minimal stringing and good strength. The white PLA used is not best quality, but works well enough.

petes-balzer-mech-printed-in-waterloo-ont-canada-13dec2019.jpg

Pete Rimmer14/12/2019 15:38:25
729 forum posts
49 photos

Cool. I hope it goes together well. Once the small gear is fitted it doesn't come off again, and the winding handle is also easier to break than remove.

Please let us know how it assembles!

Jeff Dayman16/12/2019 00:12:26
1827 forum posts
45 photos

Hi Pete, finished assembly of my device today. Assembly went well and it operates just fine. I painted the "cutter" and "relieving tool" in silver plastic model paint to focus the eye of viewers on what is actually happening at the business end. Pic below. Once again a big thanks for sharing the gcode on Thingiverse.

img_20191215_185610810.jpg

Bandersnatch16/12/2019 00:59:54
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1656 forum posts
60 photos

Pete, any chance you could publish an STL of this?

Pete Rimmer16/12/2019 09:49:09
729 forum posts
49 photos

I'm afraid not. I found online converters but have no way to test the output file so I'm loathe to just run it through the converter and share it.

Perhaps one of the other members can help? I don't mind adding the STL to the file list if someone tests it first. 'm sure that many other people would prefer that too.

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