I had built a lam grinder that was supplying decent laminations until I tried to do some really thin ones. I was having problems with the slight inconsistencies in the sanding drum. Not too long ago I bought a new Rigid bench top oscillating sander. As I was using it I started eyeballing it as a potential lam grinder. I thought about it for a while and this is what I have come up with.
This first photo shows the lam sled guide set as far away from the sanding belt as possible. it also shows the feather board set where it gives a nice pressure to keep the lamination against the sled guide. Note that the lam sled guide is resting directly on the bench grinder table which is square to the sanding belt.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0656.jpg)
This second picture shows how the lam grinder attachment is attached to the bench grinder. Three C clamps. It is simple and secure. The thickness adjuster is a 1/4 20 screw that is threaded through a piece of oak that was glued and screwed to the base. I did tap the oak and then smother the threads with cyanoacrylate (CYA) and then tap them again. on the right side of the photo you can see the 1/2 inch dowel that I used as the lam sled pivot.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0654.jpg)
This last photo shows the lam sled adjusted very closely to the sanding belt. I still have to make my lam sled but using the grinder as it is is very simple. As always the key is to push the laminations at a smooth and steady pace.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0653.jpg)
:)
pete
Nice creative solution. Did you see something like this or just totally make it up. Jim
Ingenious solution Pete. I am impressed.
Jim,
I made this one up all by my lonesome. Took what I liked about my other one and got rid of what I didn't like.
I have finished my sled and will get the pics posted tomorrow.
pete
That's pretty slick. I have the same sander. Hum that definately gets the wheels turning.
Shawn
Can you show it in use? Having never seen such an operation, I'm not sure how you feed the lam through. Is this just for parallel lams or will it do tapers as well?
Looks pretty cleaver. I have one of these sanders too. Wish my shop was heated so I could work through the winter!
Steve,
Here are a few shots that should help you understand why/how this thing works. First one thing missing in the previous shots is the sled. It is a key piece. The sled is the piece with the dowels sticking up from the top. The dowels are to give you a good grip to control the feed speed. The sled is run through the grinder to make the face of the sled perfectly parallel to the grinding belt. In this picture you can see the sled and a lamination positioned for grinding. This setup will give you a parallel lamination.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0657.jpg)
In this next picture my finger is touching a tapered lamination that is placed directly against the sled. This is a lamination that I bought from a supplier that was already ground with a .002 inch per taper. (one hint, You can see the writing on this lamination. I write all over them so I don't accidentally grind one or use it in a bow.) By placing a parallel on top of it and then running it through the grinder you will duplicate the taper. Note the stop that is glued to the end of the sled to stop the laminations from kicking back.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0660.jpg)
In this next photo I am pointing to the lamination that will become a tapered lamination when it is run through the grinder because of the taper that is positioned against the sled. Note that the stop is thick enough to catch this lamination also.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0659.jpg)
One last thing I would like to point out is that I have made a new feather board that is the full height of the laminations. This should work better than the 3/4 inch piece that I had built originally. I will try and get some video posted tomorrow while I am actually grinding laminations.
pete
Very clever! I love a good jig, and this one might just be my next project. Thanks for sharing! :thumbsup:
Thanks for the pics Pete.
Shawn
I have the same sander and was thinking about doing something like that. The only concern is the up stroke of the sander. Dose it cause the lam to rise up?
Cant wait for the video.
Cobbow
cobbow,
It looks like he is using the belt sander, not the spindle sander. I don't have the Rigid, yet, but my guess would be that the belt sander doesn't move up and down as it spins, as the spindle sander attachement does.
BTW, great idea and ingenuity!
The belt does go up and down
you could always add a featherboard to the top of the lams to keep them from shifting up and down as the belt is moving up and down. You're template lams will have to be made the same width as the lams you're grinding, or you'll want to make the lams your grinding wider then the template lam so the featherboard rests on it.
I have the same machine pretty sweet rig. I definatly wished the belt didnt occilate to the point I'd give up the occilation on the spindle also!
First, Thanks for the interest and the compliments.
As far as what I am using,it is the belt sander. Yes it does oscillate up and down. The oscillation is no problem at all. IT is actually a benefit. The fact that the belt oscillates evens out the slight imperfections of the belt that would be ground in to the lamination. I do not set the grinder up super aggressive. I use many passes to remove wood. This practice of using "Light pressure" eliminates the issue of the lamination trying to shift up or down.
Another reason I am using the belt sander is because the roller on this end is hard plastic and has a truer surface than the rubber rollers. I have actually had the rubber rollers give me a slightly concave surface on my previous grinder. I will try them and check which gives me a better lamination.
dinner then video session. I hope to post later tonight.
lookn forward to it Pete!
AUGHHH :knothead:
I can't get photobucket to load the video! :banghead: I am going to keep trying. It may have been too long. I will do some single shots. I have since learned that the spindle gives a nicer finish than the belt. SURPRISE< SURPRISE!
here is a little clip of the thing in action. I am still in the learning curve with this toy so I will leave you with this and pick up again tomorrow.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/th_DSCN0668.jpg) (http://s214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/?action=view¤t=DSCN0668.flv)
with what I have done so far I am happy with the results.
pete
looks good Pete, I may have to try that one, already have some lams from omc as templates for tapers.
I was wondering why there isnt a feather board on the outfeed side holding the sled to the fence face like on the infeed side? Do you think I'd need one? are you running acrossed just the wheel end or the hole belt?
that looks great! I have the same sander and Ive been trying to figure a way of doing the same thing. I have had some problem with a little play in the belt sander when I push wood up against it. It usually results in the bottem part of the wood being sanded a little less than the top, resulting in an uneven thickness. Have you run into this problem with your Rigid? Oh and I have checked the table and it is perpendicular to the belt.
Pete. Thanks for entertaining all our questions. Especially my dumb ones!! What exactly does the feather board do? It seems like it would just get ground off. How did you make it?
Steve,
a feather board is there to keep the material being cut up against a fence. When doing my strip canoe I built them out of 1x4's, cut some slits up them on the bandsaw and c clamped them to the table. the ends arent a 90, I think mine were more like 30 degrees or so, I dont think it really matters TOO much. Basically when it's pushed up against the stock you want held to the fence, the featherboard holds it there and has some give with all the fingers so you can push it through.
I am curious what you made your featherboard out of Pete...maybe a close up shot of it?
Tommy
I Will double check that thickness issue caused by the play in the belt sander itself. I have a feeling that that problem, if it does exist on my machine, would be taken care of by the sled. The face of the sled is ground just like the laminations are, so any play would be addressed in the sled. It would have pushed the sanding drum/belt over and eliminated the play in the first 1/4 inch of grinding.
I did grind a bit last night but did not get anything down to the critical stages. I am going to wax the back of the sled and the fence to decrease the friction between the two. I am also going to recheck the square and flat of the sled. It may have developed a slight bow since it was cut from the 9/4 board. IT is the little things like this that can drive you nuts when you are trying to be this accurate.
Steve, to add to wahat AkDan said about the featherboard... and what you noted... Yes it does get ground off. What it does is pushes the material that is being ground right up against the sled. It keeps quite a bit of pressure there. Enough that it also helps keep the sled up against the fence. It also helps to stabilize the lamination right at the sanding drum.
To make mine i ground a piece of hickory to about 1/16 thick and glued it to a block of wood. The feather board is actually flat. THe curve is forced in to the wood by the design. The first time you use the grinder you will grind the feather board off to exactly where it needs to be.
I will get some more pics tonight.
pete
Pete, I use a similar set-up to grind my lams as well. It does a fine job once you get the hang of it. It is a slow process though. I ordered some 36 grit sleeves that sped things up considerably.
Thanks again Pete. Have you found the angle of the fence to the spindle/belt to be critical? I would think that since the lamination face is touching a single point on a curve it doesn't really matter?
Are you measuring the thickness of the laminate as you reduce it till you get the thickness you are looking for, or do you measure the space in between the sled and roller? If you are grinding a pair of lams for a bow, do you grind both lams at each setting before readjusting the sled?
Steve,
The angle of the fence to the spindle has no impact what so ever to the grind. As you point out it is a curved surface so we are grinding against a single point on the curve.
As far as measuring...
This comes from previous experience with my other grinder...
Measure the thickness of the lamination not the space. I always measure about 2"-3" back from the end of my taper for the butt thickness. When I finish grinding I cut the taper where the actual desired measurement was obtained. The reason for this is that regardless of how careful I am at starting the grinding process the beginning is always a bit "shakey". We are dealing with thousandths here. The fact is if you watch the video carefully on the second pass you will see where the front of the sled comes off the table for a moment because I got careless. In a perfect world my fence and infeed table would be 2 feet longer so that the sled was fully supported the entire length of the grind. The second reason I measure the taper is because each time you run the taper through the grinder even when you do not change the adjustment you remove a bit of wood and the results are measurable. The fact is the last 10 thousandths or so are taken off the taper by running it through the same setting 4 or 5 times checking the measurement each time.
When I grind lams for a bow I grind them all at the same setting one at a time, then set the fence closer and grind them all again. Just make sure that you know which ones are ground and which ones need to be ground. I also mark the taper so the thin end and the thick end are easily identifyable.
As promised... here are the pics of the feather board.
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0670.jpg)
(http://i214.photobucket.com/albums/cc105/longbowpete/lam%20grinder/DSCN0671.jpg)
I did check the spindle and there is no play in my machine. I did not check the unit with the belt sander attachment.
I also checked my fence and my sled for true against my steel straight edge. There was, as I suspected, a slight bit of warp. I used the steel and a sanding square to bring them in to square.
pete
I'm getting close to running out of questions! Do you feed the butt end or the taper in first? Does it matter?
I feed the end of the taper that will be the butt end first.
pete
Pete, are you running it paralell to the belt at a slight angle to the belt or grinding on the wheel alone....kinda hard to tell in the pic?!?! Guess I'm missing this one. I'm going to build this jig on my day off this coming week, gotta love working 12's 8 days in a row shew.
Thanks for the pic of the featherboard, definatly better idear then what I use on my table saw LOL!
Cool beans Pete! I really appreciate the time it took to share this with us. I may have to try this myself!
AkDan, Sorry I too have been doing the 12 hr days, BUt hey, I have a job so I aint gonna complain. I run the taper across the round part of the belt or on the spindle only, not the flat part.
pete
I hear the job gig Pete....I aint complaining toooo much ;) .
Thanks for that info! I dug my sander out, got to working on some 4 wheelers these last couple days, back to work tomorrow for a couple day yay.
up
Been wondering Pete how thick the lams when you start and what did you saw them on?
Barley,
This next part is almost embarrassing to share! I Live in the Pocono Mountains of Pennsylvania. I am blessed with the fact that there are a lot of good local hardwoods around here. Woods like, Maple, Ash, Hickory, Black Walnut. What I did was find a local saw mill that harvested the local woods and would pick up a board or two of rough sawn 10/4 wood. I would then take it home and turn it in to lam slats on my circular saw. By the way the key is a good blade (YEa I spent $40 on one and will never go cheap again) One day while I was at the mill Dan, the guy who owns it asked me how I was making my lams. (he had already taken an interest in the bows that I had shown him that I had made from wood I purchased from him.)When I told him Dan very politely, but with the requisite glint in his eye, told me that I was doing part of his job and he would show me why.
This was when I had my eyes opened for about the third time by this wood master.
We took the ash, hickory and black walnut boards I had just purchased over to the back of his shop. There standing in its glory was a band saw that had a blade that was two inches wide. The feed in table was 6 feet long and the run out table was 10 feet long. The adjustable fence spread from 3 feet in front of the blade to three feet behind it with a second fence behind that one. HE asked me HOW THICK??? Yea that glint was still in his eye... 3/16 of an inch if you could. In about 2 minutes he had the fences adjusted. He asked if I was comfortable manning the run out table. SURE!!! as I was wiping the drool from my chin.
In less than 15 minutes I had a pile of lam blanks I couldn't believe. The waste from the band saw was negligible and the cuts way better than what I was able to do on any of my saws. This is what I took home that day!
(http://i214.photobucket.com/albums/cc105/longbowpete/sweet%20water%20bow%201/DSCN9821.jpg)
The moral of this story is to go in search of a local saw mill. Look in the yellow pages, Talk to guys who build furniture, Ask anyone you know.
pete
Pete, where in the Pocono's do you live. i used to live in Dingmans Ferry and really miss that area.
Tony
I live by Marshalls Creek. Down by East Stroudsburg. It used to be nice but... well lets just say it has gotten way to crowded for my taste.
Dingmans Falls are still beautiful.
pete
It is always nice to fine that local, bandsaw man... very cool...
Mike
Hey Pete
I just got my interpretation of you lam grinder built this last weekend. My jig takes up a little more room than yours but gives me more of an in and out feed table. I will post pics when I get home. I wish we had more maple around here it is all oak and a few walnut.
Thanks for sharing your ideas
Cobbow
pete i don't live too far from there ---
whats the name of the mill?-if you don't mind
that looked like some nice stuff
Here you go I am going to give this a try. First time to post a pic.
(http://i944.photobucket.com/albums/ad290/jcobb613/shopprogects003.jpg)
(http://i944.photobucket.com/albums/ad290/jcobb613/shopprogects005.jpg)
another shop project
(http://i944.photobucket.com/albums/ad290/jcobb613/shopprogects002.jpg)
Bamboo,
I will send PM
cobbow,
Three things if I may,
1. What year is the Vett under the tarp?
2. I am moving the adjustment screw away from the spindle, What would be the left in your picture to give me a finer adjustment.
3. I wanted to do the larger in feed / out feed table but was not able to find a piece of wood that was flat enough. Is the birch ply stable enough? Did you add anything to make it flat? Any problems keeping it at a perfect 90 to the spindle? The birch at the local home center was not nice.
and thanks for sharing your improvements!
My next improvement is CNC aluminum sleds!
pete
Good eye its my Dad's 64 327ci 365hp 4sd. He had it in high school, sold it to marrie my Mom, buoght it back with only an extra 2,500 miles. Oh that was 25 years after he sold it.
The bed was just some scrap we had around. I didnt do anything to flatten. The guild is squar to the spindle I check it before running anything.
I did notice how sensitive the adjustment is I may end up dooing the same.
I dont know how long the sled will last. may have to find something more stable. It would be nice to be able to have a cnc avalible. I'm just a simple wood worker. I am still learning how to build bows and to do it right.
Cobbow
Hey are you grinding new lams for my new longbow on that machine. Just wondering
Love the thread, I have the same sander and will be copying! If you are looking for a stable, flatter surface for your jig, try some MDF.
I've just about given up trying to buy flat plywood, too.
Metsastaja
Yes Your lams were the first sets ground on my new grinder. Glue up this weekend depending on the "Storm of the century" YEY!
Cobbow,
Rusty old cars is one of my other hobbies. I rebuild a clunker every year or so. Nothing like that Vett though. I saw that before the sander in the pic! I wonder where my priorities really lie?
I don't have personal access to a CNC. What I do have is the ability to swap a bow for a set of jigs... if you get my drift.
Jered
The surface of the jig is easy. the grinder takes care of that for you. IT is the infeed outfeed table that I am worried about. I kept mine limited to the sander top. The longer infeed out feed is going to be way more accurate with a good table. Will MDF stay true over the length?
pete
Pete,
A couple of questions:
How is the sander holding up? The reason for the question is I have the same sander and set up a lam grinding jig similar to yours last spring. After about fifty lams the bearings on it developed a wobble and I wasn't able to get smooth lams anymore. I replaced the bearing but it still wobbles too much to use for lams.
The biggest problem I found (when the sander was working properly) was getting a constant feed when pushing the lams through the jig. Any deviation in the push speed and the lams got low or high spots. Have you had that problem?
I had some coated MDF (the type used for shelving and cabinets) left over from another project and used it for my jig; It worked good and provided a square, slick surface. It is set up with adjustable wing nuts and a dial micrometer that allowed really fine adjustments without any guessing. If I get a chance, I will take a picture this weekend and post it.
Walt,
I have only made 8 sets of lams so far. Like you said the speed at which the lam is fed is critical for controlling the depth of the cuts. Another thing that I have found is how much wood you removing in one pass. I only remove a little bit of wood each pass and I feed the lam through the grinder 3-4 times each setting keeping a light touch. This makes it easier to have that desired consistent feed speed...
Thanks for the heads up on the bearing issues. I will keep that in mind!!! Has anyone else experienced this? I am surprised that after re bearing you did not get the same accuracy back. What type of bearing did you replace it with? Do you remember?
pete
Pete, I replaced the bearings with new ones from Rigid.
Walt,
I am really glad you pointed out the bearing problem. Do you have any idea why the wobble remains? Was the bearing a tough install? I am really going to look this rig over and see what I come up with. No reason to re invent a wheel that doesn't work!I do look forward to seeing yours.
pete
Pete. thanks for sending the pictures of the bow I'm excited.