2x42 Treadmill motor “upgrade”? A better option?

WoodenMonkey

WoodenMonkey

Joined
Oct 28, 2012
Messages
90
Hi all! Ive been reading a lot of threads about this, and finding a lot of good info, and just wanted to open a conversation because every situation is unique and why not talk about it some more? You dont have to waste your time if its a waste of time for you 😉.
Im a new knife maker and like many, im getting my start with a used 2x42 that works well enough but i sure would love to have some speed control! (Also, like many…) I dont have a lot of money to throw into this just yet So my current thought is (was) to add a tread mill motor (which i already got free and stripped the motor and controls.) to the other side of the arbor. The control panel is so bulky that it seems ridiculous to try and actually use so ive been researching dc motor controllers and other options…
I could go on and on about my “ideas and all that” but basically, the more i read, the less it seems worth putting the time and effort in to following through with this idea… but i will if i dont find a better way.
So, instead of spending (more) hours and hours digging and fumbling and experimenting, i figured id ask the people that have a lot more experience than i do at all of this!
Does anybody have a better idea they’d be willing to share about how to give my 2x42 variable speed control until i can upgrade to a proper grinder? Motor options? Controller options? My ideal way would be to get a good 3phase motor and vfd that i could transfer to a 2x72 chassis whenever i can manage that upgrade, but again, money is the limiting factor there.
Any thoughts or suggestions would be most welcome!
Thanks to anyone who wishes to engage. And apologies if this post is beating a dead horse with a lump of poorly forged iron…
-Gabriel
 
All right all right, Bryan from “Housemade” kinda says it all here…

I’m still open to any other ideas/suggestions that might help until i can scrounge together enough to get the proper motor and vfd set-up. Besides, “just suck it up and take your time” which is a totally valid answer too.
 
A 3-phase motor and VFD are the best option. 1HP will be plenty. It will run 2X72 later on. Eventually you can upgrade to 2HP.
Now, if the price of a pre-wired package is more than you can handle, you can DIY with a cheap Chinese VFD and a 3-phase motor.
I'm getting rid of a good bit of my ridiculous motor stash. Send me an email and let's see if I can send you a motor and maybe a VFD.

Side note:
For years most grinders had at most a 1HP motor, then it was 1.5HP, now you see everyone say, "2 to 3HP is what you want". 1HP is a lot of power, 3HP is really a lot of power. The first production line cars by ford had 4HP motors. You can do fine in a hobby knife shop with a 1Hp to 1.5HP motor. Until recently I had 1.5HP as my biggest grinder motor. Same for disc grinders. 1HPis more than enough. 3/4HP works just fine.
 
Stacy E. Apelt - Bladesmith said:
A 3-phase motor and VFD are the best option. 1HP will be plenty. It will run 2X72 later on. Eventually you can upgrade to 2HP.
Now, if the price of a pre-wired package is more than you can handle, you can DIY with a cheap Chinese VFD and a 3-phase motor.
I'm getting rid of a good bit of my ridiculous motor stash. Send me an email and let's see if I can send you a motor and maybe a VFD.

Side note:
For years most grinders had at most a 1HP motor, then it was 1.5HP, now you see everyone say, "2 to 3HP is what you want". 1HP is a lot of power, 3HP is really a lot of power. The first production line cars by ford had 4HP motors. You can do fine in a hobby knife shop with a 1Hp to 1.5HP motor. Until recently I had 1.5HP as my biggest grinder motor. Same for disc grinders. 1HPis more than enough. 3/4HP works just fine.
Click to expand...
I sent you a message using the “send message” button in your profile, is there a better way to get in touch? Im sure you have a lot of messages and things to look at so i imagine its pretty easy for things to get buried.
 
Welcome to the madness WoodenMonkey WoodenMonkey :)

I was recently in the market for a new motor and drive for a disc grinder. One thing to take in to account when reviewing these, is the shop environment. For me, that means dusty and sometimes hot. For this type of "shop environment", I prefer a NEMA 4 rated enclosure for the VFD which protects the sensitive electronics. Additionally, a TEFC motor (totally enclosed fan cooled) will usually fit the bill for durability. I would certainly take these in to account when making a judgement for the long haul :thumbsup:

John
 
Stacy E. Apelt - Bladesmith said:
A 3-phase motor and VFD are the best option. 1HP will be plenty. It will run 2X72 later on. Eventually you can upgrade to 2HP.
Now, if the price of a pre-wired package is more than you can handle, you can DIY with a cheap Chinese VFD and a 3-phase motor.
I'm getting rid of a good bit of my ridiculous motor stash. Send me an email and let's see if I can send you a motor and maybe a VFD.

Side note:
For years most grinders had at most a 1HP motor, then it was 1.5HP, now you see everyone say, "2 to 3HP is what you want". 1HP is a lot of power, 3HP is really a lot of power. The first production line cars by ford had 4HP motors. You can do fine in a hobby knife shop with a 1Hp to 1.5HP motor. Until recently I had 1.5HP as my biggest grinder motor. Same for disc grinders. 1HPis more than enough. 3/4HP works just fine.
Click to expand...
As you probably know I've got myself a 2x72. I have a 1hp with a 24d. I'm willing to spend the money on a KBAC-27D, just need to put a motor to it. I can find decent prices on 1.5hp made in America motor. If I hung out on eBay for a few weeks or more I could probably find a 2hp Leeson or Baldor that looks good. Would it be a big jump going with the up to 1.5 from the 1hp. Also, I have searched threads here that say go 1750 over 3600 and just double the speed at the VFD. And how can you tell exactly if a 1750 motor is acceptable to doing that? Also what will be the amp draw on a 1.5 vs. a 2hp with the 27D? I have a 40yo electrical panel at a house that was never intended to be running high power tools.
 
My first 100 knives were made on a homemade grinder using a 1 1/2 Baldor and I never had any issues with it getting bogged down no matter how much I leaned into it. My second grinder I built with a 1hp Baldor and same thing, no problems at all, plenty of power for me. When grinding if I didn't know already which grinder had the 1 vs 1 1/2 , I wouldn't be able to tell which one is which.

When I first came here reading most post on the subject suggested anything smaller than a 2hp was junk and would easily bogged down. My thoughts are most people bogging down their grinders were probably using a pulley setup so they could change speeds ,nowadays most grinders direct mount the motor and I think that let's you use a smaller motor. Now I'm sure somebody out there could easily bog my grinder down but I think most people would be satisfied with the performance of 1hp when mounted directly
 
Can't help with 2hp amp info but maybe this helps. Both of these motors came from ebay under 100 shipped. Ben a while ago though.


20230730_011714.jpg20230730_011500.jpg
 
If you have 220VAC available, you can get a Chinese open frame VFD for about $50 or $60 these days. You need to be mindful of dust getting in and shorting them out, but they're very capable VFDs.

As for the motor, keep an eye on your local facebook marketplace, craigslist, and even eBay. A local motor repair shop may also have some used options, or if you know any industrial electricians, mechanics, or HVAC techs, you can ask them to keep an eye out. If you're patient, you can probably find a usable motor for $50 to $100, if not free.
 
Britt_Askew said:
My first 100 knives were made on a homemade grinder using a 1 1/2 Baldor and I never had any issues with it getting bogged down no matter how much I leaned into it. My second grinder I built with a 1hp Baldor and same thing, no problems at all, plenty of power for me. When grinding if I didn't know already which grinder had the 1 vs 1 1/2 , I wouldn't be able to tell which one is which.

When I first came here reading most post on the subject suggested anything smaller than a 2hp was junk and would easily bogged down. My thoughts are most people bogging down their grinders were probably using a pulley setup so they could change speeds ,nowadays most grinders direct mount the motor and I think that let's you use a smaller motor. Now I'm sure somebody out there could easily bog my grinder down but I think most people would be satisfied with the performance of 1hp when mounted directly
Click to expand...
Drew Riley said:
If you have 220VAC available, you can get a Chinese open frame VFD for about $50 or $60 these days. You need to be mindful of dust getting in and shorting them out, but they're very capable VFDs.

As for the motor, keep an eye on your local facebook marketplace, craigslist, and even eBay. A local motor repair shop may also have some used options, or if you know any industrial electricians, mechanics, or HVAC techs, you can ask them to keep an eye out. If you're patient, you can probably find a usable motor for $50 to $100, if not free.
Click to expand...
Britt, Thank you for that insight. And maybe they aren't changing belts soon enough :D

Yeah I could go the Housemade route and buy the cheaper VFD and put it in an enclosure. I have been looking on FB, CL, and eBay 👍
 
So after lots more research and learning, I have decided to just move forward with the dc treadmill motor for now. I already have it and it was free so why not see how long I can make it work?
I’m going to use an SCR voltage controller with a bridge rectifier to convert the ac to dc, and then a dc motor choke to clean up the “noisy” power coming from that setup. And I got some stainless steel 120 mesh to make a filter to try and keep the metal dust out.
From what I’ve learned, besides the metal getting into the motor, the other major issue that shortens the life of the dc motors is not using a choke to clean up the power.
This video shows (at the 12min mark) very clearly what happens when you don’t use a choke in the scr controller sequence:
This guy, DazeCars is a wealth of knowledge about treadmill motors. A great resource!
 
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