Author Topic: Circle mill question .... (Read 2314 times)

TexasTimbers · « **on:** February 09, 2006, 09:09:16 am »

I'm fixin to buy This Tachometer that I found referenced over on the chainsaw forum and wondered if I can use this tach to check the rpms on my circle mill when I get it set up?. I don't know because I've never even seen a tach so it is probably a dumb question, but I want to make sure and buy a tach that will work on both my chainsaw and the circle mill.
This leads me to my second question. I have heard that beofre I send my saw in to be checked/hammered etc., I have to tell the sawist (?) what rpm I will be running the mill. So how do I determine what rpm I should run the saw?
If it matters, I will be cutting hard and softwoods.

Fred · « **Reply #1 on:** February 09, 2006, 10:11:23 am »

Not sure About the tach but the saw shaft should turn at 600RPM or as close to that as you can get.
Fred

D._Frederick · « **Reply #2 on:** February 09, 2006, 10:43:24 am »

I doubt that the chain saw tack would be accurate enough to get within + or - 100 rpm of your saw speed.

I think that Grainger is still sell the counter type tack. You hold the counter on the end of the shaft and time it for a minute, the reading is your rpm.

TexasTimbers · « **Reply #3 on:** February 09, 2006, 03:21:36 pm »

Okay Fred, 600 RPM I didn't know there was a standard rpm.

D, I looked at Graingers and found one for $550. Sheesh. More thahn I need. Gotta be a cheaper route since I won't be using it very often. I'll keep looking.

Buzz-sawyer · « **Reply #4 on:** February 09, 2006, 04:10:49 pm »

600 rpm isnt standard........there is no standard.......you need to pay real close attention to this detail of your mill.......you need to base the running rpm of your power plant to the rpm you have the saw doctore hammer your blade to ,"STAND UP" this is critical to prevent blade malfunctions, heating and other yuck stuff......

What you need to be asking is, what is the governed running rpm of my power plant and how fast is your mandrel turning at that speed???

TexasTimbers · « **Reply #5 on:** February 09, 2006, 04:33:49 pm »

Okay, so the blade will stand up at whatever rpm that all the physics of the blade itself decide, the doctor will hammer it to run optimally at this rpm, and then I'll just run it at the rpm the good doc tells me to?

I have 6 blades and I doubt they are all good, should I pick what looks like the best two and send them in or one at a time?

Buzz-sawyer · « **Reply #6 on:** February 09, 2006, 04:52:28 pm »

KEV
What happens is you hammer on the side of the blade in circular patterns tha are variabe...........this adjusts the tension in the disk, the man doing the hammering, is the only determinig factor, as to what rpm it will stand up straight, and no longer be dished.........the centrifical force of differing speeds is what overcomes the dish beat into the blade....................you must determin up front what you want the blade to run at....there are several schools of thought on this.....the more recent is faster blade speed....I dont like as well as the slower speeds....550 for example.........

TexasTimbers · « **Reply #7 on:** February 09, 2006, 05:07:32 pm »

Okay I uynderstand it a little mo betta. I think.

So, you like 550 better than 600 ..... I know there must be a reason, would you please elaborate?

Buzz-sawyer · « **Reply #8 on:** February 09, 2006, 05:22:30 pm »

I like the slower rpm for several reasons.....I am not sure it really makes as much difference but here are my feelings.
I think the spped of the blade at say700rpm means you are likely to be visiting the saw doctor, maybe two times as much as me (Based on what a few guys have told me)
It seems to take more attention and maitenace to run those rpms.....I also like to use a fairly heavy gauge blade for the same reasons....another thought I have is , in the case of hitting foreign objects.....your gonna be hitting them twice as many times at hight speed as a slower blade............
I can easily cut in the 1 foot a second range...with my homemade old fashioned sawmill running at slow rpms....just seems like the better idea not to run things faster than ya need to.

NOW MR Wienrich and Brokaw MAY have opposing views...they run bigger productionmills and may have different feelings.

Ron Wenrich · « **Reply #9 on:** February 09, 2006, 05:30:53 pm »

I think a lot depends on your power input and the type of mill you have. I have sawn with saws as slow as 350 and as fast as 700. 350 RPM was an old Frick with Detroit 471. I told the owners to move it faster, but they said not to, since that is what it was set up before.

I'm running 700 RPM on an automatic with 150 HP electric. When I ran diesel power units, I kept it around 550 RPM. Seems to be the standard for those types of power units.

What I have found out is that saws are more forgiving at slower RPMs. That means you might not have your saw filed as good as it should be, but you can still cut wood. At the higher RPMs, you better have your saw adjusted right or you will be off line.

As for the extra trips to the saw doc, not necessarily so. It depends how much trash you hit. I usually get them hammered once or twice a year. I also have the shanks changed once a year. I usually get a couple of million bf in each hammering. And, some guys abuse their saws, and some don't.

Sunfield Hardwood · « **Reply #10 on:** February 09, 2006, 05:52:06 pm »

Hi Kevjay, I ran a small circle mill for about 10 years before buying a bandmill, You will learn to be a real "millwright" before long, it takes constant vigelace to keep sawing straight, I bought an infared tach online from Harbor Freight. you stick a small piece of reflective tape to whatever you want to check the speed of, it works great, I think it was $39. they did'nt have it in the catalog, I found it while shopping their website, Goodluck

D._Frederick · « **Reply #11 on:** February 09, 2006, 10:27:02 pm »

What ever kind of power plant you have,whether its gas, diesel, or electric, you need to know how fast it is going to turn your saw arbor. You will need to know the rpm so that your saw doctor can hammer the saw to that speed.

With a gas or diesel engine the rpm will decrease as the saw is fed into the log. You will have to estimate how many rpm your power unit will pull the saw at. If your power unit is still being serviced by the mfg. like Cat or Cummins, you should be able to get the torque curves for your engine. These curves will give you the rpm under load that you should be running the engine at.
If you estimate the rpm, you may have to have to have the saw doctor fine tune the hammering.

Some of the saw blade manufactures say that the tip speed for a sawmill blade should be about 10,000 ft. per. min.. If you know the saw blade mfg, check with them. This would be a starting point to belt your power unit to the saw arbor.

isassi · « **Reply #12 on:** February 10, 2006, 06:39:29 am »

Hey Kev. I bought a "timing" tach of of E-bay...cost like 20 bucks, and works great...like to the exact rpm. Mine works by holding it to the end of the mandrel and press the timing button. It stops when the cycle is complete and you read the rpm. The old saw we had when i was a kid ran at 400 rpm or so, and I remember, it had heating problems, probably due to not enough power to maintain the rpm. I run mine at 575 @ 1925 rpm on the motor, and I guess I'm getting in the habit of checking after every log to see if I detect any warm spots (don't do this while the blade is turning

) and teeth edge. I have not had the blade hammered yet, and the past owner did not even know what I was talking about when I asked him what it was tensioned for, but I know I will do it one of these days. I have no idea what it will cost to have it and my 60" inch blade sent in for hammering and inspection.

TexasTimbers · « **Reply #13 on:** February 10, 2006, 07:28:22 am »

Lotsa good info fellas thanks.
Jay, I have been given a reference for a hammerin man in East Texas but I haven't called him yet. So's if by the time you decide to have it done if'n ya ain't found someone locally I could hook you up next time you take the missus ta Canton ta spend more of your hard-earned dough

P.S. How bout dem seeders - seen 'um yet?

ex-racer · « **Reply #14 on:** February 10, 2006, 07:43:49 am »

10,000 ft per minute is about right.

Divide 10,000 by the circumference of your saw in feet.

Example - My saw is 36" Diameter = 9.42 ft.
10,000 ÷ 9.42 = 1061 rpm

I had it hammered for 1200 rpm thirty years ago. It has lost some tension over the years and I now run it at about 1000 rpm using a Ford V8 in 2nd gear.

I use a hand throttle (similar to a motorcycle throttle cable) to help out the governor when required.

Carriage speed that gives 1/10th of an inch per tooth of "bite" will work well in softwood. I'm not sure about hardwood.

Ed

P.S. Suggest you trial run the saw. If it will stand up (run true) at your desired RPM there should be no need to have it hammered.

Ron Wenrich · « **Reply #15 on:** February 10, 2006, 12:06:49 pm »

I've never had a problem with the loss of rpm with any diesel unit. The key is to start into your cut slow, then speed up when you're in the cut. If you hit the log fast, then you can kill the rpm.

I also listen to the saw while I'm sawing. I want to keep the same tone or pitch all the way through my cut. If the tone goes down, I'm losing rpm, the saw's starting to lay over, and the gullets aren't getting rid of the dust. The saw will heat up and then you have problems.

1/10" per tooth feed rate might be OK for some logs, not OK for others. I wouldn't want to feed that way through a big old hickory just because the manual says so.

I agree that you can put the saw on the mill and try it at different rpms. Make sure your saw guides aren't touching the saw when you try it. When it runs straight, then that's the rpm to run. If you have problems, it might not be the saw's hammering that needs fixed.

isassi · « **Reply #16 on:** February 10, 2006, 01:51:55 pm »

If you used 1/10" per tooth per rpm, and my blade has 52 teeth...lets see..

5.2 inches per revolution X 575 rpm = 2990 inches per minute or 249 feet per minute or roughly 4 seconds to run 16 feet.....

That would take more motor then I have. I figured out my rpm based on the blade standing up...and over 500, stands up with no bounce. I think the technical information I read from Simmonds said somthing like 2.5 to 3 inches per revolution for softwood. Any faster, the gullets may not clear and since I run a 9X2-1/2, I have to watch it.
Kev, I haven't been out to the cedars yet, but hope to this weekend...I have been with a building inspector this morning and my head still hurts.....

Frickman · « **Reply #17 on:** February 17, 2006, 04:28:08 pm »

I use a tach I got at NAPA that has interchangeble rubber tips. You put it on the end of the shaft you're checking. I think it cost around $60.00 or so.

I'm running around 400 RPM. It seems to work pretty good. I know it's on the slow side, but the RPM's stay constant through the cut. That is very important. I've different sawyers over the years and it seems that running a little slower compensated for alot of mistakes these sawyers made. It's a stick mill, so if shrapnel starts flying you have more time to duck.

Sawyerfortyish · « **Reply #18 on:** February 17, 2006, 08:53:30 pm »

I have a tach like Frickmans. Just hold it on the end of the shaft and read the dial. When I set the mill I have now up I set the power unit at 1800rpms. Took a measurement of the pully on the mandrell and called a place that delt with pulleys. Told them how fast my power unit was running and the size pulley on my mandrell and how fast it had to run and they got my pulley for the power unit. All my blades run at 550 and I agree with the reasoning Buzz stated for not running faster.

jpgreen · « **Reply #19 on:** February 19, 2006, 03:24:04 pm »

SawyerF,

Do you have a link to that Tach?

I've been looking for one that will do that.

Thanks,

JP

isassi · « **Reply #20 on:** February 19, 2006, 07:20:23 pm »

You can find one on E-bay, I think what you are looking for is a Stewart Warner tachometer..has a range of like 1500 RPM or so. The tach I use is also help to the shaft end and tripped like a stop watch and rotates until the speed corelates, then stops. Supposed to be accurate within a few rpm, so the manufacturer says.

highpockets · « **Reply #21 on:** February 19, 2006, 07:58:58 pm »

Kevjay did you get the photos of the mill?

I don't know much about hammering blades but there is a company Smith Sawmill Service
Highway 59 South, Timpson, TX 75975. Phone: (936) 254-3161. I buy bandsaw blades from these folks. They seem to have things going on and are really nice to do business with.

Sawyerfortyish · « **Reply #22 on:** February 20, 2006, 09:35:23 pm »

jpgreen can't tell ya where mine came from it was given to me from a neighbor and is probably as old as I am.

UNCLEBUCK · « **Reply #23 on:** February 20, 2006, 11:25:31 pm »

I also use the cheap rubber tipped handheld tach . I use the tach for setting my old combines and any good machinery dealer should have one or find a farmer and borrow it for a few days . A standard farm tractor runs 540 rpm on the pto shaft and thats wide open so if it is farm tractor powered I would go like 500 rpm for a hammering so your governor will have a chance . Maybe do a dry run of your carriage at 500 rpm and see what your your carriage is doing for speed . If you cant adjust your feed rate you should really do the math carefully for the blade you want to have hammered . I take the blade off anytime I put the handheld tach on but I just dont like being in close like that .

TexasTimbers · « **Reply #24 on:** February 21, 2006, 09:19:08 am »

'pockets,

I haven't got them yet. I will attempt it today. Raining right now.
Even after I get them I may need help figuring out why I can't upload pictures anymore. i never did fully understand how I was successful at doing it in the past. I jsut kept clicking things and retrying and next thing I knew the camera and computer would cooperate and viola! I'd have pictures in folders and then I'd get them on xat.com That softawre it easy even for me but I haven't been able to get the pictures out ot my camera for quite a while now.
Anyway, I'll snap them today if it quits raining long enough and try to upload them.

jerry-m · « **Reply #25 on:** February 21, 2006, 11:05:09 am »

Kevjay,

A few other saw shops that may be close to you;

Poole's Sawmill Service
Shreveport, La.
(318) 227-1695

I haven't used them yet but my neighbor has... They have a route service that will pick up and return...Just don't know how often they come by or how far they will come... They come to the Longview, Lake O Pines area... They told me they would make an apointment to get me in and out the same day if I wanted to bring the saw in to them... My neighbor got good service from them on the route service, but he has an extra blade to keep from being down waiting on the blade to be returned... I think he got his blade back in just 3 or 4 days...

Smith Sawmill Service
Timpson, Tx.
(936) 254-3161

I have used them... They got me in and out in about 45 minutes... The person that hammers the saw is only there on certain days so call first... I think I will use Poole next time I need my saw harmmered as they never asked me what rpm I was running my saw???

Pine Creek Saw Inc.
Rt 1 Box 477
Valliant Oka. 74764
(580) 933-7376

I have not used them and they were recomended by someone here on this Forum...

If you don't mind I would like to know what town you are close too here in Centeral East Texas???

Thanks, Jerry

TexasTimbers · « **Reply #26 on:** February 21, 2006, 12:13:27 pm »

Hi Jerry,

Thanks for that information. I'm near Bonham which is NE of DFW halfway between Paris and Sherman.
I come to Winnsboro and Tyler frequently. I need to come to Longview one day to visit Satterwhite, and look over their timbers. I've talked to Don over the phone about purchasing kiln dried cut to order beams at a price which seems too low to be getting good structural stuff suitable for timber framing.
I don't want to buy them for my home because I insist on being bone-headed and using the free/cheaper stuff at my disposal but looking at it for future source possibly.
Have you been by there per chance to eye that stuff? Most folks think they deal in logs and log kits only. But they have timbers too. Don said they carry mostly decorative beam stock but in the lenghts I was asking about (only up to 20') that he thought they'd be suitable.

Guess I need to put the look-see on 'em.

jerry-m · « **Reply #27 on:** February 21, 2006, 09:45:06 pm »

Kevjay,

Sattlerwhite had an ad in the paper a few months ago for single logs, etc... I didn't pay much attention to it through, sorry...

Yeah, best to come look for yourself..

They have a pretty large outfit here... Had a large banner like 15 ft by 3 ft outside the plant looking for truck drivers a couple of week ago...

News:

Author Topic: Circle mill question .... (Read 2314 times)