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View Full Version : Biax scraper motor repair help.



lamestllama
15th May 2018, 03:17 PM
Here are some photos of the armature from my Biax 7ES. I don't really understand how it is so stuffed when the rest of the scraper shows absolutely no signs of wear.
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This did run albeit quite poorly when I acquired it a couple of weeks ago. I only noticed the missing segment when I came to have a look at the brushes.

As you can see there is a segment missing and the two either side of it are really chewed out. I am willing to spend some money to fix this. Ideally a new armature would be the solution I understand it is a fein motor but without a part number they claim to be unable to help. So the next best option is to find someone in Australia with the skills to rebuild this. Does anyone have any suggestions?

.RC.
15th May 2018, 04:43 PM
Here are some photos of the armature from my Biax 7ES. I don't really understand how it is so stuffed when the rest of the scraper shows absolutely no signs of wear.


The rest of the machine is built to last a long long time.

The armature on mine was stuffed when I got it as well. I think I found one of the only few second hand armatures in existence, although it needed to be rewound.

lamestllama
15th May 2018, 07:27 PM
The rest of the machine is built to last a long long time.

The armature on mine was stuffed when I got it as well. I think I found one of the only few second hand armatures in existence, although it needed to be rewound.


Did you manage to find any identifying part numbers? Mine is devoid of any part numbers whatsoever.

malb
15th May 2018, 10:37 PM
If it's any help, Joe Hovel had a thread a couple of years ago about converting an air powered Biax to electric by grafting in a motor from an Ozito multi function tool. The process worked well, but the armature was damaged during assembly. The project was basically a successful proof of concept exercise, but did not continue to a permanent solution due to a lack of Ozito spares to fix the motor. However virtually all major tool manufacturers have MFT's with parts support for around the $200 mark, and some of the low support units are in the order of $50-$100. Could be a worthwhile fix to consider.
Biax motor change (http://metalworkforums.com/f303/t198801-biax-motor-change)

lamestllama
16th May 2018, 01:11 AM
I have read that thread. I probably have the possibility of grafting a new commutator on this shaft and having it rewound. Joe didnt have that option. One thing I am noticing is that the Fein nibblers have a very similar looking geartrain to that of the biax. With a spiral pinion on the end of the motor shaft. Maybe a graft of a modern Fein power tool might be the go.


If it's any help, Joe Hovel had a thread a couple of years ago about converting an air powered Biax to electric by grafting in a motor from an Ozito multi function tool. The process worked well, but the armature was damaged during assembly. The project was basically a successful proof of concept exercise, but did not continue to a permanent solution due to a lack of Ozito spares to fix the motor. However virtually all major tool manufacturers have MFT's with parts support for around the $200 mark, and some of the low support units are in the order of $50-$100. Could be a worthwhile fix to consider.
Biax motor change (http://metalworkforums.com/f303/t198801-biax-motor-change)

KBs PensNmore
16th May 2018, 02:06 AM
Check out the Bosch Die grinder, they look to be similar.
https://www.gumtree.com.au/s-ad/redcliffe/power-tools/bosch-die-straight-grinder-ggs-28-lce-dms-new-warranty/1182893348

https://www.gumtree.com.au/s-ad/nedlands/power-tools/bosch-straight-grinder-die-grinder-/1174893422 $100.00

https://www.gumtree.com.au/s-ad/guildford/power-tools/bosch-die-dye-grinder-straight-grinder/1145552652 $195

You might find even a 4" angle grinder body might fit?

Kryn

lamestllama
16th May 2018, 03:17 AM
Kryn,

I am looking at the Fein range simply because i hope they will already have the 6 tooth spiral gear built into the motor shaft as per the original which is also a Fein motor. Hoping they kept that common across a few tools.

Eric

Michael G
16th May 2018, 07:41 AM
With that sort of damage, you may be better addressing your questions to professionals. I have used the guys listed below in the past for motor repairs, and have had a good job done. The 7 is a current production model I think, so the option is open to contact Biax in the US and ask them about a spare part. It will probably cost but at least you know that it is the right part and not a maybe/ maybe not fix.
The chewed up bits on either side are because the carbon brushes have knocked on the edges of the missing piece. To fix the armature you would need to make up a replacement copper segment, attach it electrically and then mechanically (Araldite or a similar glue I would suspect). Last of all you would need to do a skim cut on the whole commutator to smooth everything down. It could be done and if it were a motor where parts were simply not available at all, I'd have a go. As it is, I'd try the motor repair place first and then Biax before going there.

Michael


STATEWIDE ELECTRIC MOTOR CENTRE

7 Beulah Road, Norwood,
South Australia 5067
P 08 8362 5755

caskwarrior
16th May 2018, 09:29 AM
I think some metabo jigsaws have exactly the same drive motor and output as at least one Biax model I dont know if it's the 7es though.

jhovel
16th May 2018, 12:38 PM
I believe Michael is right in that a motor rewinder will be able to help. They will have commutators too. No need to find that yourself I suspect. However, make sure the rewinders have access to proper balancing gear - some don't. At 30 000 odd rpm, that is critical.
The current equivalent Biax models are the BL10/HM10 - neither Dapra nor Schmid & Wezel have spares for the 7 series any more.
I am NOT sure they used a Bosch motor for the 7 series - it may well have been a Fein motor... I got my intormation form this this source:
Information on BIAX type 10e? (http://www.practicalmachinist.com/vb/machine-reconditioning-scraping-and-inspection/information-biax-type-10e-310366/)
Maybe e-mailing Schmid & Wezel in Germany might give you the definitive answer.

lamestllama
17th May 2018, 12:46 AM
Michael

The BIAX is a 1970s version with no spares available. I did indeed consult a motor rewinder today and the happy news is it can be repaired. He is sending it to Melbourne because whilst he can rewind it he would have to have it balanced elsewhere whereas the company in Melbourne has machinery to do both jobs. So it is having a new commutator fitted then a rewind. The price is more than I paid for the scraper but still worthwhile considering it should then give years of service if correctly cared for.

I have to admit I was hoping for an answer like "an armature from a Fein drill or some other tool will fit" or even the exact model number of the Fein flange mount motor used(they provide them to specialist tool manufacturers as a basis for a tool) which would have been some help getting assistance from Fein who promise they will always have an alternative part.

There really wasn't enough meat in the remaining segments to take a cleanup cut that would have cleaned up the segments adjacent to the missing segment. Even if a segment could be glued in and it was appropriate to the wire to the missing segment was also snapped of. Starting from a clean slate is the right thing to do with this part.

Eric

.RC.
18th May 2018, 10:01 AM
Did you manage to find any identifying part numbers?

No, no numbers anywhere. Look slike you have got it sorted. I take it you are getting it rewound to 240V if it is 110V at th emoment.

You can also date your biax by the serial number. The last 2 digits should be the year of manufacture.

lamestllama
22nd May 2018, 12:49 AM
I got the armature back from the rewinder. New commutator and rewind are obvious but I cant see any signs it has been rebalanced other than what is written on the bill. Hopefully when the brushes arrive from Germany this thing will go back together again and provide years of service.
373424373423

.RC.
22nd May 2018, 07:49 AM
Wow that was fast service.

Looks good.

lamestllama
23rd May 2018, 12:06 AM
Wow that was fast service.

Looks good.

Yes the turnaround was impressive. It apparently went to Melbourne to someone called Terry who has a machine that can wind and balance these small armatures. Dropped it of with David Osman at Marion on Wednesday afternoon and got it back on Monday afternoon. I can't tell you how well it works yet as I am waiting on brushes from German ebay that have only been in the post since last Monday.

I also have to figure out how to pull an 8mm id bearing that is in a blind hole at the back of the motor. I am wondering about a modified dynabolt unless I suddenly walk into someone with a blind bearing puller that fits.

KBs PensNmore
23rd May 2018, 01:17 PM
Hi Eric, using a sliding hammer with a hook on the end is about the only way I know of, to get something like that out.
Hope this helps,
Kryn

.RC.
23rd May 2018, 02:51 PM
Turn up a nice fitting punch that will fit into the ID of the bearing. Fill the bearing hole with grease, put punch on top and hit it. The grease will pop the bearing out, or at least move it.

pippin88
23rd May 2018, 09:10 PM
You can also do RC's trick with bread if you don't have any grease spare...

jhovel
24th May 2018, 02:37 PM
I've used small strips of rag myself and have even heard of people using toilet or tissue paper soaked in oil or grease. If the bearing doesn't have a shield or seal on the blind side, grease by itself may just get forced through the bearing if the bearing is tight. By using something like bread or paper or anything else that will block/clog up the bearing, the hydraulic force applied by the tight fitting pin/punch that RC suggeste will push the whole lot out.
I've done that numerous times in motorcycle gearboxes using the rag strip method.

argeng
24th May 2018, 08:32 PM
Looks like a quality job.You know you will have to say what it cost! so the community of scrapers appreciate what we have paid for our Biax's.
Cheers Bruce

lamestllama
25th May 2018, 12:03 AM
The casing that the bearing is in is plastic so I am not keen to pressurize it. So I think the grease is out. The hook idea is basically what I am going to try with a dynabolt or similar device that will expand on the inner bore.

lamestllama
25th May 2018, 10:07 PM
Looks like a quality job.You know you will have to say what it cost! so the community of scrapers appreciate what we have paid for our Biax's.
Cheers Bruce

Too much! Particularly didn't like the + GST that only got mentioned after the job was finished.

KBs PensNmore
25th May 2018, 11:16 PM
Businesses have a bad habit of quoting a price and not mentioning GST, making us assume that the price is inclusive!!!
Should always ask "Is that including GST?"
Kryn

lamestllama
26th May 2018, 08:01 PM
Businesses have a bad habit of quoting a price and not mentioning GST, making us assume that the price is inclusive!!!
Should always ask "Is that including GST?"
Kryn

I keep forgetting to learn that lesson.

lamestllama
3rd Jun 2018, 06:32 PM
A short update. The brushes I won on German ebay finally arrived as did a set of Chinese blind bearing pullers from ebay. So it was time to make a move on the bearing at the rear of the motor. First step was to unsolder and move the field windings out of harms way (they both measure 9.6 ohms for those interested). 373634


This leaves the 8mm ID bearing down at the bottom of a deep narrow casing. 373635

I gave the casing a wash out in the kitchen sink telling me the guys on the metalwork forums said it was perfectly fine to do so.

373637373638

373633
I had prepared and bough a set of blind bearing pullers from ebay. As with all things you get what you pay for and the design of these is poor. When you tighten the pin into the expanding outer it is designed in such a way that the expanding outer is unsupported so the "legs" are left springy and end up pulling out of the bearing with even gentle tapping on the slide hammer.

So I resorted to drilling two 3mm holes through the housing at the back of the bearing and tapping it out with a punch. 373636

Now I have the bearings out I will procure some tomorrow and put the thing back together.

lamestllama
3rd Jun 2018, 06:39 PM
373639One more thing. Here is a photo of the parts cleaned and ready to go.

jhovel
3rd Jun 2018, 08:23 PM
Hi Eric,
I'm very interested in learning more about these blind bearing extractors.
Could you show some close-ups of the ends open and closed and maybe a sketch of the mechanism?
I imagined that there was some kind of taper plug that forced the fingers apart and heald them there in use....
What closes them and what opens them?

This is what I found in a quick search:
https://www.youtube.com/watch?v=5C4KjJ-j3u4 and
https://www.youtube.com/watch?v=eNCKmPPdNqQ

Yours are obviously made differently. Could they be improved?

lamestllama
3rd Jun 2018, 11:59 PM
The main problem is that the bores in the end and the pins that go into them are parallel. The only thing expanding the legs is the short taper on the end of the internal pin as the parallel part is too large to go through the external part when an appropriately size bearing is in place to be pulled.

373665373666373667

KBs PensNmore
4th Jun 2018, 01:07 AM
Hi Eric, thanks for the pics of the tool and tips. Can you see an easy fix for these or is it WOFTAM???
Would you recommend this tool?
Thanks,
Kryn

lamestllama
4th Jun 2018, 09:25 AM
Kryn

Not sure yet. In truth both the pins and the bore they expand in should be tapered for these tools to work properly. I can fix the pins easily but boring out something that is slit two ways seems near impossible given the equipment on hand. Especially in the desired 8mm size.

Eric

lamestllama
4th Jun 2018, 10:01 PM
373696373695
My Biax 7/ES breathes again. New commutator and armature rewind, new bearings and new brushes. It has absolutely no wear on the sliding faces so I am expecting to get many years of service from this tool.

The bearings are 6001-2z and 608-2z both C3 the brushes are the same as for the 7/EL model and a guy on German ebay was selling those for 8 euro a set so I bought a three sets. I am awaiting a new cable strain relief grommet from Hong Kong and this project is finished.