What's new
What's new

Biax 7EL Fiber Gear

Dick Streff

Aluminum
Joined
Sep 12, 2003
Location
Omaha
I caught an edge and ended the life of the fiber gear in the old Biax 7EL I have. I seem to recall a discussion several years ago about this gear and the inability to obtain it. In the interim has anyone found a source?

Thanks,

Dick
 
if you can't source one it would probably be worth getting someone to measure up an NOS gear and have a small batch made up to sell on ebay.
 
I caught an edge and ended the life of the fiber gear in the old Biax 7EL I have. I seem to recall a discussion several years ago about this gear and the inability to obtain it. In the interim has anyone found a source?

Thanks,

Dick
Ask Ed Dyjak 2486844260, doubtful but you may get lucky

Sent from my SM-G935V using Tapatalk
 
I am pretty sure that we got as far as RE'ing the gears from a forum member's Biax, but cannot for the life of me recall if we ever went as far as actually making the replacements. ( if we did, maybe the person they were made for will speak up ) For some reason I want to say that they found a donor tool at the last second. I'll have to look through my notes this weekend.
 
Longtime since the original post but I made some progress replacing the gear in this scraper that might be of help for others in the same situation.

I was starting with the gear remains in this condition and the information previously posted in the thread from 2016.

Original Gear.jpg

I did some preliminary calculations and eventually obtained all the bits needed to helical mill on the Cincinnati machine I now have. I came up with a sacrificial gear with the dimensions as follows:

No. Teeth-37
Module-0.7mm
Helix Angle-18 degrees

I only had a small piece of phenolic on hand to experiment with so I decided to model the gear in Fusion360 and have a someone at work use the 3d printer to make a prototype in PLA as a check. It seemed to mesh well. I even ran it under speed but without a load and it sounded OK and didn't instantly self-destruct. It got me thinking if there were any other 3d printer filaments that might be a good alternative to the phenolic of the original. I eventually settled on having one made in Nylon. It was about $12 delivered to my door so I ordered one while I set out to machine a phenolic version.

The scrap of phenolic I had was canvas based. In the end it might not be the best choice. I can't tell from the remains of the original but I think it might be linen based. I machined a couple gears from it and tried them out. Both eventually failed under load during use. The tooth form of both the machined examples was a bit loose compared to the 3d printed version. I think I need to refine my cutter a bit as I am using a single tooth fly cutter and the tooth profile is as best I can get ground by hand with nothing but a loupe to help magnify it.

In the interim the Nylon printed gear showed up so I tried it out. I've used it now for probably a couple hours total run time under load and it seems to be holding up very well:

Nylon Gear2.jpgNylon Gear1.jpg

I can't say it is the long term solution but it seems to work so far and the price was right. I do plan on getting some linen based phenolic and trying to machine a better version from that. Ultimately at the speed this gear operates at it would be best to have this hobbed but I don't have that capacity and not sure I want to invest the time to make one of the hobbyist work arounds to get that ability. Especially when the 3d printed solution looks as promising as it has.

I can only say this solution has worked for me on this scraper model to the limited use I have put it so far but I'd be glad to share the 3d .STL file of the gear for anyone who wants it. Not sure if I can attach that here and it might be easiest to post it to one of the 3d printer file sharing sites. Let me know if there is any interest.

Dick
 

Attachments

  • PLA Gear.jpg
    PLA Gear.jpg
    90.3 KB · Views: 39
Hey Dick,

I want to send my belated thanks for posting up this info. I had cause to need to make these gears and I used the numbers from your post above. The gears didn't turn out perfect because my hobber is only designed to cut spur gears but a working non-perfect gear is better than no gear at all and after a bit of trial and fudging I managed to produce a pair of working gears which has brought a couple of dead blue Biax machines back to life.

Blue Biax delrin gear.jpg

 
If you don't want to mess with printing a gear, this guy has them for sale. I bought one for a spare for my old blue Biax scraper.
 








 
Back
Top