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Where to buy Myford compatible change gears other than directly from Myford?

Xyphota

Xyphota

Ultra Member
I have been waiting for Myford to stock a 21T change gear so I can cut metric threads as needed for almost a year now. Well I actually need to cut one now, so I’d like to order a compatible gear from somewhere else.

The Gear is a 20DP 14.5 degree pressure angle, 21T. I’ll have to double check the gear thickness, bore size and key way dimensions.

Is there a goto place for ordering stock gears?

Additionally, if anyone in Calgary has a Myford with a 21T change gear, could I borrow your change gear for an afternoon? ;)
 
ahh I’d seen that done before and I completely forgot that was an option! Although 20DP teeth are pretty small, so I’m not sure if the resolution of my printer will print a very nice gear. I’ll definitely give it a go!
 
Xyphota said:
ahh I’d seen that done before and I completely forgot that was an option! Although 20DP teeth are pretty small, so I’m not sure if the resolution of my printer will print a very nice gear. I’ll definitely give it a go!
Click to expand...
Worth a shot. I see South Bend Change gears on eBay all the time. Not sure of the DP. Be sure to print with a high infill percentage.
What printer do you have?
 
You can buy a set on eBay. They cost few hundred $$$. New (well, to you, used) gearbox is around 1500 plus.

This is for a whole set. single gears can be had as well. I think around $40.

You can also get a casting for the gearbox and can make all gears for the gearbox yourself. There are many options.

There are plenty of parts available. Main issue is that they cost a lot of $.
 
We’ll give this a go this evening:
47A6E1FF-8C0F-4748-8BCC-365EA682599D.jpeg
 
I resin printed one a while ago as a test, after a heated debate on the HSM forum about 3d printed gears actually being "gears". I didn't get any pics as I was too excited to go out and try it out. It worked great, BUT the resin I used was too brittle for the intended use (Elegoo black , just used what I had) and it broke after a couple heavy passes. I will admit I was pushing it to see how it would do, and have no doubt if I needed to cut a couple metric threads it would have been just fine, and I could have babied it through cutting many threads.

0nM5Rfxl.jpg

That's another "gear" I printed from the same resin for my wife's electric spinning wheel. It will last a lifetime in that use. For a change gear, I'd recommend a stronger resin than std elegoo black. Something printed in a tough filament might do, but the inaccuracies of FDM might become an issue, or they might not depending on your level of acceptability. Not sure what you filament printed yours in, or what infill, but the elephants foot might be a problem. Will probably have to face that off.

Keep us posted, I'm genuinely curious how it will fare.
 
Yeah the elephants foot is not ideal, but I think I can just have that overhang the outside face of the gear its mating with and it'll be close enough. I just printed out of standard PLA so I dont expect this to hold up for very long. I would have gone with PETG if I had it on hand.

Additionally, I do see that RDG Tools has a 21T gear instock which is especially infuriating because they are the same company as Myford, and I just had an order ship from Myford last night :mad:. The invoice on the myford order even says RDG Tools LOL.

EDIT: Although to be fair, I have ordered some parts from RDG Tools before and found out after I ordered them that they were out of stock, so perhaps this 21T gear is not actually in stock as indicated by the Myford website
 
Xyphota said:
I have been waiting for Myford to stock a 21T change gear so I can cut metric threads as needed for almost a year now. Well I actually need to cut one now, so I’d like to order a compatible gear from somewhere else.

The Gear is a 20DP 14.5 degree pressure angle, 21T. I’ll have to double check the gear thickness, bore size and key way dimensions.

Is there a goto place for ordering stock gears?

Additionally, if anyone in Calgary has a Myford with a 21T change gear, could I borrow your change gear for an afternoon? ;)
Click to expand...

Which Myford do you have? QC Gearbox?

I have a Super 7 and needed 33 & 34 tooth change gears to cover pretty much any metric pitch, maybe you have another model that would need the 21 tooth?

I got my gears through the local office of BDI Canada and they were $55.63 each, one was stock & one came from BG. Looks like you have a BDI in Calgary too.

The gears are made by Boston Gear and the model numbers look like GA33 & GA34. They might have stock somewhere in Canada or might need to bring in from BG, in any case it didn't take long. UPDATE: Looks like the GA21 is CDN non-stock ($57.42) so it would have to come from Boston but they probably have stock.

I needed to do some clean up on the key way so that the gears would slide nicely onto the shaft.

Not impressed by RDG, I've been waiting many months for them to get stock of the two step drive pulley (5/8 bore, anyone have one laying around?) and they can't tell me when they might have some or let me know when they come into stock. Some day it might come up on my priority list to just go ahead and make one but I'd rather just buy it, no guessing on dimensions.

@Redneck_Sophistication you might find a replacement gear for your saddle drive in the Boston Catalog too. Boston Gear Spur Gear Catalog

D:cool:
 
I have a Myford ML7R. I'm really only interested in the common metric thread pitches of 0.75, 0.80, 1.00, 1.25, 1.50, so for those you only need a 21 tooth change gear on top of the gears you would otherwise already have for imperial thread pitches. I am thinking about purchasing the Manchin Gearbox Kit from Hemingway Kits, and maybe the taper attachment kit. I am currently making a solid tool-post mount for my Myford so I think having a taper attachment would virtually eliminate the need for the top slide.

EDIT: Change Gear Chart below:
 

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  • Myford Change Gear Chart.jpg
    Myford Change Gear Chart.jpg
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Ah, OK, that's a little different animal than my S7.

Hopefully BDI can help with the 21T change gear.

D:cool:
 
YotaBota said:
@Tecnico - is there a reason you haven't turned the pulley yourself?
Click to expand...

@YotaBota It just hasn't come up high enough on my to do list to make it worthwhile to go to the trouble of figuring out the dimensions of the two grooves and making the part. Even the material would come to about $40 and RDG lists them at $37 CDN so if/when they get stock it's not worth the hassle. I spoke to them about shipping and I don't remember what it was but it wasn't going to be expensive.

I have so many projects in the hopper that it's not anywhere near the top of the list (until I get something I really need it for LOL!)

You don't have one under your work bench do you?;)

D:cool:
 
The ML7R and super 7 should have the same spindle and headstock, so I'm pretty sure the change gears on both sets are the same. Where did you determine that you needed a 33 & 34T change gear?

Unrelated, I discovered today that my cross-slide and top-slide lead screws and indicators are both metric, and display diametric increments - i.e. One turn of the dial increments 4mm per revolution and the tool only moves 2mm. This is extremely annoying LOL.
 
Hmmmm....., if your ML7-R doesn't have the QC gear box then I don't think the 33 & 34T change gears will do what you need for metric threading since they combine with gearbox settings.

I think you're back to the 21T solution but that still means Boston Gear/BDI can help.


For background and for any Myford QC gearbox users here's some info on using the 33 & 34T change gears to do metric (and other) pitches:

There are a number of threads at model-engineer.uk about the 33 & 34 T change gears for a Super 7 with QC gearbox including charts showing the possible pitches including some pretty arcane threads. See:

Myford Super 7 screw cutting gears (mertic)

Yet Again! Metric screwcutting Myford Super 7

Arcane chart

Note that some of the pitches described in the table are not perfect conversions but as the authors point out they are so close that for most cases it does not matter. The variation is usually in the third place after the decimal.

Chart showing % error

D:cool:
 
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Tom Kitta said:
You can buy a set on eBay. They cost few hundred $$$. New (well, to you, used) gearbox is around 1500 plus.

This is for a whole set. single gears can be had as well. I think around $40.

You can also get a casting for the gearbox and can make all gears for the gearbox yourself. There are many options.

There are plenty of parts available. Main issue is that they cost a lot of $.
Click to expand...
casting for the gearbox, NOW THAT'S COOL - fun project.
Thanks
 
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