Dremel bits for inletting/bedding stocks with aluminum blocks

[rickyw]

For those of you who have prepped a stock for bedding that has an aluminum block, what dremel bits do you prefer to shave away some of the aluminum in order to give space for the epoxy? I bought some cheap carbide bits off amazon that were supposedly made to shave metal and rock and within a matter of minutes the ends that contacted the aluminum were completely dulled out on three of them - waste of money. Thanks

 

[wapitibob]

I've never removed any of the aluminum, I added .005" shims to the block or pillars.

 

[rickyw]

I've never removed any of the aluminum, I added .005" shims to the block or pillars.

Essentially skim bedding? Or are you just adding shims with no epoxy?

 

[Macintosh]

Im not sure removing aluminum from a bedding block is a good idea in the first case, the whole purpose of that block is to have a non-compressible surface for the action to mate directly to. Is there a problem with the block? Generally you bed around it and only any areas the action doesnt already contact would have a layer of epoxy, and it’ll get squeezed out from the areas where it contacts leaving them exposed. It may be a different sort of block than ive run into though?

 

[rickyw]

Im not sure removing aluminum from a bedding block is a good idea in the first case, the whole purpose of that block is to have a non-compressible surface for the action to mate directly to. Is there a problem with the block? Generally you bed around it and only any areas the action doesnt already contact would have a layer of epoxy. It may be a different sort of block than ive run into though?

So you skim bed?
I was under the impression that removing a bit of material where you wanted to bed, 1.5 mm or so, would make a more stable bedding job

And yes the rifle does not sit straight in the aluminum block. And visually you can see the block was not made to tight tolerances and is slightly canted. I like bell and Carlson but they have their issues at times

 

[TaperPin]

I like the ones with a round head, but many shapes will shave a little off the surface.

Keep in mind aluminum will often plug up carbide burrs. Oven cleaner (lye) will eat the aluminum without damaging the carbide.

 

[rickyw]

I like the ones with a round head, but many shapes will shave a little off the surface.

Keep in mind aluminum will often plug up carbide burrs. Oven cleaner (lye) will eat the aluminum without damaging the carbide.

View attachment 846798

Thank you. Do you have a specific brand you like?

 

[TaperPin]

Thank you. Do you have a specific brand you like?

There are probably better brands out there, but I’ve been happy with Dremel since they are at the local Home Depot or Lowe’s. It is also a good idea to not spin them too fast or they plug up much faster. Definitely get the solid carbide model - high speed steel doesn’t last long.

 

[Macintosh]

Get some other feedback specifically on blocks, I have more experience bedding wood stocks with pillars, but generally you have pillars or a block or mini-chassis at least in theory as a solid fixed surface specifically so that mating surface is at a very precise dimension already. You can relieve some area around it to get good adhesion of the bedding compound around there, but the bedding compound is usually allowed to squeeze out from where the action actually mates with the block leaving no thickness where they actually touch--it's only the gaps that get filled in and have any have thickness of bedding. That maintains the dimensions of the block while fully supporting the action and preventing torque. IME the bedding is there only to fill the gaps that would otherwise cause stress when the action is tightened. The bedding blocks I've had were all sort of a "vee" so the mating surface was very narrow and there would have been some thickness of bedding around that, so other action shapes may call for a different approach. If you're worried about adhesion you may only want to create some recesses in the block for the bedding to fill-in and mechanically lock into? You can mill out the bedding block fully if you want, but you will run the risk of losing the thickness of the pillar height, and may need to play with the depth of the trigger guard and magazine as a result--just seems like asking for a much more complicated job than needed.

This thread has some opinions on bedding like this as well as some pictures, what was milled out, etc. It's more focused on full-on chassis and mini-chassis which may be a bit different than what you have, but hopefully helps. From the thread: "

"I think you’ll find most smiths just skim bed aluminum V-block chassis. There’s plenty of space already there for the plastic to fill...."

The "a chassis should not need to be bedded" myth........

The topic comes up ever so many months and you'll find quite a lot of people will chime in with the blind "you shouldn't have to bed a chassis" line. The recent "what the pros use" chassis article from Precision Rifle Blog revealed some numbers I think many will find surprising. Before getting...

www.snipershide.com

 

[rickyw]

Get some other feedback specifically on blocks, I have more experience bedding wood stocks with pillars, but generally you have pillars or a block or mini-chassis at least in theory as a solid fixed surface specifically so that mating surface is at a very precise dimension already. You can relieve some area around it to get good adhesion of the bedding compound around there, but the bedding compound is usually allowed to squeeze out from where the action actually mates with the block leaving no thickness where they actually touch--it's only the gaps that get filled in and have any have thickness of bedding. That maintains the dimensions of the block while fully supporting the action and preventing torque. IME the bedding is there only to fill the gaps that would otherwise cause stress when the action is tightened. The bedding blocks I've had were all sort of a "vee" so the mating surface was very narrow and there would have been some thickness of bedding around that, so other action shapes may call for a different approach. If you're worried about adhesion you may only want to create some recesses in the block for the bedding to fill-in and mechanically lock into? You can mill out the bedding block fully if you want, but you will run the risk of losing the thickness of the pillar height, and may need to play with the depth of the trigger guard and magazine as a result--just seems like asking for a much more complicated job than needed.

This thread has some opinions on bedding like this as well as some pictures, what was milled out, etc. It's more focused on full-on chassis and mini-chassis which may be a bit different than what you have, but hopefully helps. From the thread: "

The "a chassis should not need to be bedded" myth........

The topic comes up ever so many months and you'll find quite a lot of people will chime in with the blind "you shouldn't have to bed a chassis" line. The recent "what the pros use" chassis article from Precision Rifle Blog revealed some numbers I think many will find surprising. Before getting...

www.snipershide.com

Thank you sir. I’m actually following Nathan fosters instructions in his book on rifle accurizing. The integrity of the aluminum block is maintained but the goal is to just create enough space that the epoxy will be 1.5-2mm thick

 

[Desert_Muley]

An old bench rest shooter and gunsmith taught me to just rough up the surfaces so that the bedding material had something to grab. In order to ensure the barrel is even in the channel he used layers of tape. Remember to tighten the screws evenly equally snug.

 

[Shortschaf]

I would personally just rough the aluminum surface with low grit sandpaper.

Don't crank the action screws tight when you are setting the action on the compound, and you will have enough bedding thickness to do the job

My current bedding job is see-through in some spots it is so thin

 

[rickyw]

I appreciate the insights. It sounds like everybody is recommending a skim bedding job. Skim bedding was not my goal and I’m too far along for that and will either destroy or succeed. So far it’s been kinda fun. Thanks

 

[wapitibob]

Essentially skim bedding? Or are you just adding shims with no epoxy?

skim

 

[gbflyer]

Scratch it up with 180 or 200 grit. Acid etch and alodine is good too. Get it very clean with distilled water, and dry thoroughly. No reason to dig out the aluminum.

Nathan has tipped back a few too many Fosters.

 

[rickyw]

I think Nathan knows how to make a rifle accurate and can shoot long in field conditions better than most of us, regardless of peoples opinions of his ballistics research. It makes sense in my mind at least to have a little thicker epoxy to make it more durable. There is plenty of aluminum left in this stock. Im probably removing 5% of it.

The intention of the thread was not to ask for bedding advice, though I appreciate the well meaning responses.

 

[SDHNTR]

Zero reason to do more that slim bedding over an aluminum block. Any more defeats the purpose of the metal.

 

[rickyw]

Is a thin layer of epoxy in a skim job more prone to cracking?

 

[fuzzymarindave]

Often when working with aluminum I found slower rpm is better.

 

[rickyw]

Often when working with aluminum I found slower rpm is better.

That may have been my problem. Thank you