# Belt drive for a Grizzly G0704 mill



## hauch35 (Feb 18, 2014)

Is it possible to somewhere purchase a belt drive upgrade for a Grizzly 0704 mill or is it something I must get piece by piece. I just need the kit for the drive not the motor. If anyone can direct me I would appreciate it.


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## wrmiller (Feb 18, 2014)

I've been in contact with BenchTopPrecision.com and Scott just told me that he should start taking pre-orders next month.

I also found a place in AU that sells one, but you have to buy the motor and controller with it. I'm holding out for Scott...

Bill


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## hauch35 (Feb 19, 2014)

That kit looks pretty good. I wonder what the difference is between the v groove pulleys and the timing pulleys. Seems to me that the timing pulleys would not require the belt to be as tight. I think I'll wait on this set up too if it isn't too expensive. Thanks for the lead Bill.


Bob


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## darkzero (Feb 19, 2014)

Yep, timing belts don't require as much tension. They also won't slip, that can be a good or bad thing. With a V belt it has the chance of slipping if a mishap were to occur & act like a clutch, well depending on how tight it is. May not save much & something most likely will get damaged but a timing belt does not have that chance. If the pulleys are slightly out of alignment the v belt self aligns. With a standard timing belt alignment is more of an issue. V belts are also cheaper & readily available. So if you ever needed a replacement belt in a hurry, a v belt could probably be found at the local auto parts or lawnmower shop. I don't really see the need or advantage of a timing belt in this case but either one is fine.


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## hauch35 (Feb 20, 2014)

Those are some very good points that I hadn't thought of. Think I'll go with the v belt. Thanks for the tips.

Bob


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## SEK_22Hornet (Feb 20, 2014)

I built my own belt drive for my G0704 - here is the thread on that project. It was not too difficult and so far is working nice.  It can be built using nothing more than a mini-lathe and the mill itself. A rotary table helps but is not completely necessary. Cost was less that $100.

http://www.hobby-machinist.com/showthread.php/18468-Belt-Drive-Conversion-for-Grizzly-G0704


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## Smudgemo (Feb 20, 2014)

What in the world do you guys have against easily destroyed, perpetually back-ordered nylon idler gears?


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## SEK_22Hornet (Feb 21, 2014)

Smudgemo said:


> What in the world do you guys have against easily destroyed, perpetually back-ordered nylon idler gears?



Hmmm, let me think on that for minute or two...


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## chuckorlando (Feb 21, 2014)

I take it these machines have problems your modding to fix? I only ask because it is on my consideration list if a used machine dont pop up sooner then later. I dont want to buy a turd or even mild headache


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## Smudgemo (Feb 21, 2014)

chuckorlando said:


> I take it these machines have problems your modding to fix? I only ask because it is on my consideration list if a used machine dont pop up sooner then later. I dont want to buy a turd or even mild headache



They're fine machines for a bench-top mill.  I considered the belt mod, but  didn't feel like I was ready to give it a go.  I did buy a couple of the  nylon gears when they became available, but of course, when replacement  parts are on hand you don't wreck any and I haven't since.  If you find a used machine in good shape and it fits your needs, go for it.  Just buy an extra gear unless you do the belt mod.  Grizzly shows them in stock now, but when I needed one, it took 3 months being out of stock before I was up and running (hence my cynicism.)

-Ryan


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## SEK_22Hornet (Feb 21, 2014)

Some people have good luck with the G0704 and never seem to strip a gear - my first gear let go a week after I bought the machine new and I also had to wait 3 months for a replacement. I bought two - the second gear let loose in about a month. It is most likely my fault - trying to use larger cutters on hard steel and being a newbie, probably trying to push things too hard. That's when i decided to give belt drive a try. It was easier than I expected it to be and I think I'll like it a lot.  Just been too cold to use it much since I finished the conversion. It does get you a higher spindle speed and a quieter, smoother running machine.  I also now have a round column RF30 type mill drill to use for heaver projects (got it at an auction for a couple hundred bucks while I was waiting on parts for the G0704). I really like the G0704 but if you are heavy handed like me, it may not be the best choice - go for a belt drive mill to begin with. In my case, I probably should have bought the little HF or WT knee mill that is just a little more money - heavier machine with step pulley belt drive.


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## wrmiller (Feb 21, 2014)

I have yet to have any problems, and have talked to people (including Matt) who have never broken a gear. I have cut hardened steel in my PM25 with no problems, but I made sure that I used the smallest cutter I could to lessen the load on the machine. I talked to one person who was upset because his broke taking a rather large cut with a 1" end mill.  :thinking:

The reality is that this isn't a BP, or even a PM45 for that matter. You push it, you take your chances.

My primary reason for going to a belt drive is to eliminate the losses in the geartrain, get higher rpm, and eliminate the patterning from the gear train. I bought some steel spur gears that I can use, but I'm holding out for the belt-drive/spindle kit as I believe that would be the better solution. Assuming I can afford it of course. 

Bill


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## chuckorlando (Feb 21, 2014)

Thanks for the replies guys. If I went bench mill it would be new or really really cheap. I'm looking for a bridgeport but just aint finding anything I want in my budget. When I do I'm late to the show for drive time or school. I dont need a BP but thats what I am aiming for.

I dont mind being nice to the machine. Just so long a it does the job. We have plenty big machines at school if I needed one and I'll be there for a good bit. I just want more machine time, bench or square column and capable. 

Thanks for answering me. Sorry for the high jack. Awesome looking belt drive. If I buy one I'm sure this will be done at some point.


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