ML7 Bull Wheel Dimensions?

Does anyone have a drawing of an ML7 Bull wheel and tooth profile?

I want to design and print a lock for chuck removal.

I think there's a free .stl somewhere, but I can't find it, plus I'm stuck in self isolation for 10 days so might as well improve my Fusion 360 skills instead of staring out of the window.

Thanks.

My ML7 bull wheel is 3.315 inches O/D and has a thickness of 0,625 inches. The gear has 65t and from those figures it must be 20DP. I can't help with the PA but logic says that it would be 14.5 degrees.

HTH

Dave

Thanks very much Dave.

I struggled to find it too

Google is getting worse/less useful

I want to design and print a lock for chuck removal.

The post Ady1 linked to above has a link to a ready designed ML7 spindle bull gear lock.

I printed one for a contributor on that thread, who is testing it & will report in due course. From conversations about the Thingiverse lock, it apparently fits well and works as intended. Durability is still being assessed, but looking good last I heard.

Depends if you are just looking for a part to do a job, or looking for the design challenge !

Nigel B.

Nigel what filament did you use for the bull wheel lock please? I thought either PETG or ABS. I find PETG surprisingly robust.

JC

Nigel what filament did you use for the bull wheel lock please?

Just a generic PLA, JC.

IIRC it was Anycubic brand PLA, white, printed at 200C on a 60C build plate, 5 perimeters, 6 top & 6 bottom layers with 70 % gyroid infill. The part was flat in the build plate, so the loads applied in service are at 90 degrees to the layer lines.

I have yet to venture beyond PLA, but from what I have seen (CNC Kitchen tests on YT particularly) PLA is stronger than the other popular options, but is more brittle & has a lower maximum operating temperature. PETG & ABS appear to be more ductile so don't fail as suddenly as PLA, but start to deform at lower loadings.

But take all that with a large pinch of salt, as I am still very much feeling my way with 3D printing !

The part in question has a lot of teeth in contact with the bull gear, so a lot of area to shear - the parts I printed are apparently holding up well so far in testing. I have a Super 7, so can't test them myself.

Nigel B.

Hello,

I have just posted my interim findings on the ML7 spindle lock on the other topic entitled "ML7 Spindle lock". Results so far are astonishingly good, with the print standing up to some serious force, without any signs of breaking.

Andrew

Thanks all, I might as well just print the one on thingiverse if it works...I'll find some other Fusion project to do while sitting out self-isolation.

I have just printed one (in PETG) and found it perfect for the job.

JC

I printed one yesterday in solid PLA - works fine, apart from It doesn’t fit when the back-gear grease nipple is fitted: It won’t sit low enough to engage with the teeth in order to slide left onto the bull gear.

Addison Gray posted the original files for the ML7 version to thingiverse. 20Dp 20 pa gear on ML7. PLA 5-6 layers of perimeter, top/ bottom and 20% infill using a 0.2 or larger Layer height will perform. ( PLA stronger than PETG/ABS when printer, thicker layers stronger than thin, just like an I beam the perimeter does the work, so no point high infill.)

He and I gone on to develop indexing versions of these for both ML7 and S7, picture in album.

20 DP YES, but 20 PA?

Rather thought that Myford gears were 14.5 degree PA.

You might get away with 20 PA since there is no relative motion between the lock and the gear.

Howard

Howard yes 14.5 PA. SORRY. It will not let me edit to correct? Only this post?

Edited By PETER ROACH on 20/02/2022 16:42:22

Edited By PETER ROACH on 20/02/2022 16:44:27

You only get a short time after posting in which to edit. After that bit is set in stone!

Once the "Edit Post" icon vanishes, that' it!

Howard

You only get about 30 minutes to edit a post Peter. Allows enough time for typos etc to be fixed. Old posts can't be changed because threads become seriously confusing when that's allowed.

If a mistake is seriously embarrassing you can ask a moderator to fix it.

Dave